The

Secret
of
Chess
by Lyudmil Tsvetkov
The Secret of Chess
Copyright © 2017 Lyudmil Tsvetkov

All rights reserved. No part of this publication may be reproduced, stored in a retrieval
system or transmitted in any form or by any means, electronic, electrostatic, magnetic tape,
photocopying, recording or otherwise, without prior permission of the author.

2
 Table of Contents

In lieu of a foreword 16

Basic definitions and abbreviations 20

Chapter I
Material and major corrections of piece values 21

The piece values 21

General remarks concerning the piece values 21

Piece square tables 22

King psqt 22

Pawn psqt 23

Knight psqt 23

Bishop psqt 24

Rook psqt 24

Queen psqt 25

Pawns on squares the colour of the own bishop 25

Specific conditions amplifying or changing the weakness 26

Blocked pawns on squares the colour of the bishop 26

Central and semi-central blocked pawns on squares the colour of the bishop 27

Central d4/e4 isolated pawn, blocked by an enemy minor outpost 28

d3/e3 twice backward pawn on square the colour of the bishop 28

Special rule for the imbalance knight vs bishop 29

Special rule with bishop on more advanced ranks 29

Knight with blocked pawns 30

Bishop vs knight with pawns on both wings 32

3
Chapter II
Mobility 33

Knight mobility 34

Bishop mobility 34

Rook mobility 35

Queen mobility 36

King mobility 37

Pawn mobility 38

Available double pawn pushes 40

Low and zero mobility pieces 41

Low mobility pieces on the edge 41

Zero mobility pieces on the edge 42

Zero mobility pieces not on the edge 43

Zero mobility king 43

Permanently trapped minors 45

White knight on b1, trapped by enemy pawns 45

White knight on a1, trapped by own pawns 46

White bishop on b1 or a2, trapped by own pawns 46

White knight on b1,a2,a3 or c1, trapped by own and enemy pawns 47

White bishop on c1,b2 or a3, trapped by own pawns 47

Self-trapped bishop 49

Chapter III
Pawns 50

Strong pawns 50

Aligned pawns 50

Defended pawn 51

4
Distant neighbours 52

Very distant neighbours 53

Blocked pawns 54

Levers 56

Outer central levers 57

Defended outer central lever 57

Unopposed lever on the 4th rank 58

Lever on the 3rd rank 58

Passed pawns 59

Protected passed pawns 60

Connected passed pawns 60

Minor pieces blockading passers 61

Centralised blockading minors 62

Pieces attacking the square in front of an own or an enemy passer 64

King supporting passed pawn 64

Restricting passer 65

Spearhead connected passer 66

Rollercoasters 69

Unstoppable passed pawn 71

More pieces with passed pawns 72

Passer-makers 72

Potential passers 73

Pair of potential passers 75

Mainstays 75

Compact pawn structures 76

5
Twice aligned pawns 79

Twice defended pawn 80

Defended aligned pawn 80

Defending aligned pawn 81

Long chain pawn 82

Very long chain pawn 83

Spearheads 84

Weak pawns 85

Undefended pawns 85

Isolated pawns 85

Fixed isolated pawn 87

Knight and pawn immobilising enemy isolated pawn 87

2 pawns controlling the square in front of an enemy isolated pawn 88

Pawn controlling the square in front of enemy doubled isolated pawn 88

Pair of central isolated pawns 89

Vertically isolated pawn 90

Squeezed pawn 91

Doubled pawns 92

Distance between doubled pawns 94

Restricting enemy doubled pawn on its 3rd rank 95

Blocking an enemy doubled pawn on its 3rd rank 95

Pair of doubled pawns on adjacent files 96

Tripled pawn 96

Backward pawns 97

Standard backward pawn 97

6
Twice backward pawns 98

Twice backward feature 100

Semibackward pawn on the 2nd rank 102

Unbackwarded pawn 103

Backwardmakers 104

Unopposed backward-maker on the 5th rank 104

Central unopposed chain backward pawn 105

Central backwardmakers 105

Distant backward pawn 108

Backward long chain pawn blocked condition 109

Minor piece controlling the square in front of enemy backward pawn 110

Root pawn 110

Attacking root pawns 110

Double root pawn 111

Control of center 112

Central piece attacks 112

Minor piece simultaneously attacking with an own pawn one of the 4 centralmost
squares: e4,e5,d4,d5 113

White pawns on e4,d4, black pawns on e5,d6; or white pawns on e4,d4, black
pawns on d5,e6 113

The best move or semi-central pawns controlling the center 115

Central bind 118

Closed position considerations 119

Closed center 119

Space advantage with closed center 120

Pointed chains 121

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Inchoative pointed chains of 2 pawns 123

Larger inchoative pointed chains 124

Central chain knight blockade 125

Fully closed side with space advantage on the other side of the board 126

Weak spots 128

Own minor pieces controlling a weak spot 129

Symmetrical aligned pawns 129

Pawn span 131

Space advantage on both sides of the board 133

Chapter IV
Outposts 134

No-pawn-defended outposts 135

Single-pawn-defended outposts 136

Twice-defended outposts 137

Twice-defended knight outposts on the 5th rank with no enemy pawns on the same
file as the outpost on more advanced ranks 138

Permanent minor piece outposts 139

Outposts blocking enemy pawns 141

Useless outposts 143

Unretreatable knight outposts 144

Semi-outposts 145

Minor piece behind an own pawn 145

Minor piece with an own pawn diagonally in front of it 145

Minor piece with an own pawn on the same rank across a file 146

Minor piece on the 4th rank with an enemy pawn on its second rank on adjacent
file that is backward 146

8
Minor piece with another own outposted minor one rank in front on adjacent file 147

Minor piece on the 4th rank with another own minor piece outposted on the 6th rank
on adjacent file 147

Knight on the 5th rank with enemy knight on the 6th rank on adjacent file 148

Minor outposts on the 7th rank defended by a pawn 148

Twice defended knights 149

Rook outposts 150

Rook on the 6th rank, defended by pawn 150

Rook on the 7th rank, defended by pawn 151

Twice defended rook on the 6th rank 151

Rook outposts blocking enemy pawns 152

Penetration points 153

Chapter V
Imbalances 155

Pair of bishops 155

Pair of bishops with enemy side having no bishops 156

Pair of rooks vs queen 157

2 minor pieces vs rook 158

Queen and knight 158

Queen and pair of knights 159

Rook and bishop 159

Pair of rooks 160

Pair of knights 161

Rook, knight and bishop 162

Queen and bishop vs queen and rook 162

9
Queen vs 3 minor pieces 163

Queen vs rook and 2 minor pieces 164

Queen vs 2 rooks and a minor piece 165

Rook vs 3 minor pieces 166

3 minor pieces vs 2 rooks 167

Rook and minor piece vs queen 167

2 minor pieces vs queen 168

Queen pair 170

One side having one piece more 171

One side having 2 pieces more 172

One side having 3 pieces more 172

Opposite colour bishops with one side having a piece more 173

Chapter VI
King safety 173

Enemy king attack 174

King shelter 174

Pieces attacking the enemy king shelter 175

X-ray attacks upon the enemy king shelter 176

The knight attack that does not fit anywhere 176

Unchallenged attacking bishop 177

Bishop shelter attacks with opposite colour bishops 177

Bishop pair with kings on opposite sides of the board 178

Additional piece-attacking considerations 179

Rook on open edge file with enemy king on adjacent file 179

Rook on g or b open file with enemy king on adjacent edge file 180

10
Rook on the same closed file as the enemy king 181

Rook on adjacent closed file as the enemy king 181

Queen on the same closed file as the enemy king 181

Rook on the same semi-closed file as the enemy king 182

Rook on adjacent semi-closed file as the enemy king 182

Kingside presence of pieces 182

One open and one semi-open file or 2 semi-open files against the enemy king position 183

Storming pawns 184

Unblocked storming pawns 185

Blocked storming pawns 186

Storming pawns with kings on different sides of the board 187

Openers 188

All storming pawns blocked 189

Edge storming pawn blocked by enemy king 189

Twice defended storming pawn on f5 or c5 191

Minor piece controlling the square in front of an own or an enemy storming pawn 193

Filling the gap 194

Pawn shelter 194

Isolated pawn of the king shelter 196

Doubled pawn of the king shelter 196

Backward pawn of the king shelter 197

Twice backward pawn of the king shelter 198

Semi-backward pawn of the king shelter 200

Weak spots of the king shelter 201

Own minor pieces defending a weak spot of the king shelter 202

11
Colour deficiency with weak spots of the king shelter 202

King safety related queen pins 203

No pawn shelter 205

No own pawn on the 2nd rank within the shelter 206

Single own pawn on the third rank within the shelter 207

Minor piece shelter 207

Minor piece on the 3rd rank within the shelter 208

Minor piece shelter defence 208

Minor outpost stopping enemy rook on an open file, with own king on the same
or adjacent file as the rook 209

Immobile shelter pawns 209

King on a fully closed side 211

Exposed king with blocked center 212

King in the center sheltered by defended pawn 213

King on semi-central file, sheltered by a defended pawn 213

Kingside fianchetto 214

Trapped rook 217

Temporary prevention of castling 218

Ability to immediately castle 219

Chapter VII
General piece activity and coordination 220

Attacks among pieces 220

Direct attacks upon enemy pawns and pieces 220

Penalty for pieces attacking an enemy defended pawn 224

Forks 225

Hanging pawns and pieces 225

12
X-ray attacks 226

X-ray attacks past the second intermediary object 228

Checks 230

Safe checks 230

Unsafe checks 231

Double checks 231

Potential checks 232

Potential discovered checks 232

Pins 234

King pins 234

Queen pins 235

Skewers 236

Pawn defence 237

Piece defence 238

Defending pawns 240

Minor piece defending passed pawn 241

Central isolated pawn, defended by minor 241

Undefended pieces 242

Rook on a semi-open file, attacking an enemy pawn-undefended pawn, defended

by a minor 243

Threats 243

Safe pawn push threat 243

Unsafe pawn push threat 244

Tactical levers 245

Tactical pawn threat 246

13
Tactical lever threat 246

Knight attack threat upon enemy queen 248

Rook on open file 248

Queen on an open file 249

Rook on a semi-open file 249

Queen on a semi-open file 250

Rook on the 7th rank 250

Queen on the 7th rank 251

Doubled rooks on the 7th rank 251

Doubled rook file control 252

Royal battery 253

Continuous rook control 254

Rook on the same file as enemy queen 255

Queen and bishop battery 255

Minor outpost stopping enemy rook on an open file 257

Minor piece attacking a square on the 8th rank on an open file, simultaneously attacked
by an enemy rook 258

Minor piece attacking a square on the 1st or 2nd ranks on an open file, simultaneously
attacked by an enemy rook 259

Rook supporting a friendly pawn from behind 259

Preventing enemy minor penetration 260

Stopping bishops on long diagonals 261

Raking bishops 262

King restricted on an edge line 263

Pawn support for rook on an open file 264

Queen controlling the center 264

14
X-ray square control 265

Bishop x-ray-attacking the center 265

Queen x-ray-attacking the center 266

Bishop x-ray-attacking the square in front of enemy backward pawn 266

Bishop x-ray-attacking the square in front of enemy shelter backward pawn 267

Scaling down of different positions and endings 268

Scaling down of too closed positions 268

Horizontal pawn symmetry 269

Opposite colour bishops 269

Pairs of bishops endgame 270

General endgame scaling 271

Scaling with reduced number of pawns in the eg 272

Scaling of rook endgames 273

Rook vs queen fortress in the endgame 273

15
 In lieu of a foreword the term, and then finishing with
establishing its frequency in game
This is a special book. You will not find situations. In this way, it is easier to
many like this, or even a few ones. For the investigate the material.
past 10 or so years, chess has changed
tremendously, with the appearance of One centipawn is one hundred of a full
extremely strong chess programs, whose pawn. As very small terms, with values
level is reputed to be way above that of the smaller than 10cps, are indeed very
best humans. The existence of such difficult to make sense, in the book I have
programs, plus the availability of large included just terms with larger value than
knowledge databases allows us to look that one, though, there are also a few
deeper into the game of chess. Gems of the features with a bit lower value, just to
past are now debunked, the widely spice things up.
acclaimed play of world champions like
Capablanca, Alekhine, Kasparov and When looking at the values of different
Carlsen appears to have lots of gaps, with terms one should bear 2 things in mind:
a multitude of tactical mistakes throughout - those are just approximations, it is very
even their masterpieces. difficult to come up with a precise number
Thus, we understand, there is something for each and every term, there are so many
more to chess, something deeper, that terms, so interdependent, and so prone to
should be investigated. On the other hand, personal outlooks
chess computers do get improved on a - the values, although also having general
regular scale, adding some 50 elo or so significance, will be fully valid only within
each and every year. This is yet another the current evaluation framework and its
hint that we are still very far from pool of existing features. In a different
perfection even with machines. framework, with a smaller or larger pool
So, if machines play weak, and humans of terms, the specific values might be
play weak, there should be certainly a lot different.
of knowledge still undiscovered.
The values are split between mg and eg.
This books aims at doing precisely that: We are following more or less the general
uncovering part of the secrets that still are accepted definition of the boundary
not a general knowledge. between mg and eg, i.e. half of the
available piece material, so called non-
The book is split into 7 main chapters, pawn material, taking account of the
covering material and major corrections to material of both sides. Any other
piece values, mobility, pawns, outposts, approach, like using queen presence, etc.,
imbalances, king safety and general piece is much less relevant, obviously. So,
activity and coordination. Within these middlegames will be positions with total
chapters, there are a lot of sub-sections available non-pawn material for both sides
allowing for better ordering of the text. more than half of the starting non-pawn
material, and endgames positions with
The book is provided with a table of non-pawn material lower than half of the
contents and a complete alphabetical index starting material.
of terms.
The centipawn estimation is, although
Each and every separate evaluation term is seemingly a bit unusual, quite natural what
handled by giving its precise definition, an concerns refined evaluation factors,
estimation of its relative value in especially in the age of computer chess.
centipawns, expanding on the properties of With the progress of computer chess, it is

16
also believable, that our brain networks The book is based on pattern recognition,
become more intricate too. If one rather than vaguer reflections on the
centipawn is one hundredth of a full pawn, quality of certain chess positions. My
then 100cps will be equal to one pawn claim would be that, by using pattern
material, the winning or loss of a single recognition, it is possible to learn the
pawn, 50cps will be the estimate of half a basics of chess, as well as perfectionise, at
pawn material positional compensation, least 4 times faster. And this is not an
25cps will be 1/4 of a pawn material overstatement, in no way. Remembering,
positional compensation, and 10cps will be even by heart, if necessary, some 1000 or
1/10 of a full pawn. so main evaluation features, is
As positional factors are so numerous and undoubtedly the much more preferable
multi-faceted, it is only about natural that way to go than following the advice of an
they have so different and refined scores. innumerable quantity of chess handbooks
Not using such values will definitely miss and masters. Without pattern recognition,
quite a lot of the deeper essence of chess. in spite of all the invested hard work at
Besides, on the chess board, one usually playing and investigating different games,
has tens of different evaluation factors knowledge will more or less remain
worth multiple centipawns each, but less blurred, so less efficiently used in practice.
than a pawn, so adding all of those will When patterns are recognised, you might
certainly make more than a full pawn not need to play that many games and still
material compensation, something be able to immediately see the properties
measurable by all means. of a position, indicating at the right move
to make. Of course, there are no magical
Positive terms will score positive values, solutions to improving one's chess, no one
in centipawns, while negative ones, would believe in a method preaching
negative values, again in centipawns, but learning chess in a week or so, a lot of
with a minus sign before the estimate. games should be played and positions
analysed in order for a person to
The general rule is that term definitions, significantly improve one's tactical
more specifically the placement of pawns, abilities, tactics is not perfectionised in a
are given from the point of view of white, short time, but still, one can definitely
but figuring out the respective black significantly shorten one's way to the top
condition is very easy, bearing in mind by learning to recognise patterns.
that the chess board is vertically
symmetrical, so white's 1st rank is black's Every chess position is basically a set of
8th, white's 2nd rank is black's 7th, white's evaluation patterns. The best move is
3rd rank is black's 6th, white's 4th rank is always available at the current ply, it is
black's 5th, white's 5th rank is black's 4th, really not necessary to go deeper, doing
white's 6th rank is black's 3rd, white's 7th any substantial search, all one has to do is
rank is black's 2nd, and white's 8th rank is to recognise all the relevant evaluation
black's 1st. In this way, a white pawn or patterns making up a specific chess
piece on e4 will be tantamount to a black position. When you add up all available
pawn or piece on e5, a white pawn or evaluation patterns, you should be able to
piece on e6 will be tantamount to a black come up with the solution what the best
pawn or piece on e3, a white pawn or move is. Of course, in order to efficiently
piece on a1 to a black pawn or piece on a8, and flawlessly do that, one should be able
and a white pawn or piece on g7 to a black to recognise all the subtleties of a position,
pawn or piece on g2. Psqt tables are white- and subtleties are hidden in the larger pool
side only, with conversion following the of non-standard, non-generally-recognised
same rules. evaluation terms.

17
Someone might laugh at a range of terms I positional approaches, not to mention the
have enumerated, considering them as opening preparation.
non-existing and the product of my ill Of course, one might do without any
imagination, but all of you would be opening preparation at all, by just learning
surprised, if you knew how even the the successful opening feature patterns.
smallest of evaluation terms, worth some That saves time, saves memorising a lot of
couple of centipawns or so, is capable of theoretical stuff, but more importantly,
influencing the game. One more mobility lays a very sound theoretical opening
square, added to one more square attacked foundation irrespective of the changing
of the enemy king shelter, and one more opening vogue, as the best opening moves
subtle pawn feature most persons would are always one and the same, following the
neglect already makes quite a lot and same patterns, and those will concentrate
changes the course of the game as a whole. on just a few openings.

In the book, there are over 500 diagrams For the very same reasons, chess players
and around 100 tables. of intermediate strength will find this book
Concerning the diagrams, please bear in interesting. Although they are already
mind, that those are not simple fens, so do supposed to know quite some stuff, no
not check them with engines, they do not doubt these pages will still offer some
even have side to move. Rather, they are useful additions to their knowledge, in the
supposed to serve as an illustration form of patterns they have never read
accompanying specific features. Their about anywhere else.
purpose is just that: to illustrate the term.
What concerns psqt tables, well, those are I would be very much flattered, if some of
meant just as indicative values, it is very the stronger players pay some modest
difficult to have, of course, fully precise attention to this handbook, too. Their first
measurement of all 64 squares of a thought might be to totally dismiss a work
particular term, so take them with a grain of a relatively insignificant player with no
of salt. Still, their usefulness is beyond any track record at all, but here is where they
doubt, as an ad-hoc blanket value would might possibly be wrong. Because, on the
be the much worse guess, sometimes even pages of this work, there are terms and
completely unrealistic and detrimental. patterns I have never encountered in any
other textbook previously. And the number
The target audience of the book are 4 of those is far from being negligeable. So,
categories of people: I would be very happy for a quick browse
- weak chess players and possible massive criticism.
- intermediate chess players
- strong chess players Chess programmers will also find these
- chess engine programmers pages useful, as within there are terms no
one has ever published before. Psqt tables
Well, of course, weak chess players will be will also come in quite handy, as engines
helped most, when following the approach are very much accustomed to those. If
of pattern recognition. In that way, they anything, my approach is to only further
can cover couple of times faster the stress the importance and ubiquity of psqt
material they would otherwise take years tables. The wider they are used, the better,
to fully grasp and memorise. Memorising but of course, the tuning challenge will be
some 1000 feature patterns is definitely a enormous. I very much hope, that this
lot less work than memorising many handbook will contribute to the future
thousands of typical tactical positions and development of a range of chess engines,
and with this, to the advancement of the

18
overall cause of chess, as chess enthusiasts useful in generating food for thought for
all over the world will be using the very alternative implementations.
same engines the programmers prepare for
daily game play and analysis. July 2017

This book is the product of 5 years of

almost incessant concentration on chess.
Whenever possible, I have been playing
and investigating chess for 12 hours daily
and more. Playing chess games with
Stockfish and Komodo. Browsing
Stockfish and Komodo games,
investigating different databases. Then,
playing more games with Stockfish and
Komodo, and browsing and analysing
more and more of their games. Of course, I
have also looked at least twice at most of
the chess collections of all world
champions. Without knowing the past, one
can not concentrate on the future, of
course.

My chess rating, 2100+ FIDE elo, 2200+

Bulgarian rating(Bulgarian candidate
master since 1998), is indeed very
negligeable to suppose a person with such
a strength to be able to write a book about
chess, but the truth is, that it dates back 12
years. For almost 12 complete years, I
have not been playing chess officially, so
my rating stayed as it is, low, however, my
actual strength has increased at least 4-
fold. It is only after I finished playing
tournament chess that much stronger
engines, allowing to better train your
skills, appeared, and in the last 5 or so
years, engine strength reached its peak. So,
I trained a lot my chess during the time I
was an inactive player, and, in the last 5
years, I almost entirely devoted my time to
chess. It is possible that I am a very strong
chess player indeed, but currently, my
abilities still have not been measured in
any official way.

Since the appearance of the Stockfish

framework, I have contributed a lot with
ideas to it. At least 20 evaluation patches,
based on my ideas, have been integrated in
Stockfish code, and a lot more have been

19
 Basic definitions and abbreviations are idyosyncracies, but the basic rule
should hold.

Basic definitions psqtise assign psqt values for a specific

term
open file file with no own and enemy
pawns on it
semi-open file (possible just from the Abbreviations
perspective of a specific side) file with no
own pawns and one enemy pawn on it cp centipawn
closed file file with one own and one cps centipawns
enemy pawn on it mg middlegame
semi-closed file (possible just from the eg endgame
perspective of a particular side) file with psqt piece square table
one own pawn and no enemy pawns on it;
the reverse of a semi-open file

blocked file closed file with the own and

enemy pawns blocked

opposed pawn pawn that has an enemy

pawn on the same file

unopposed pawn pawn with no enemy

pawns on the same file

centipawn an evaluation measurement

unit, one hundredth of a pawn

piece square table a table with values for

the 64 board squares, sometimes just some
of them, for particular evaluation features.
Such tables are extremely useful and
productive, as just about any chess term
could be beneficially assigned different
values for all 64 squares. This would
actually be the right scientific approach,
but I understand the problems of engine
developers, having to tune their numbers,
and also those of humans, who would need
to memorise some dozen-fold stuff.
Memorisation is not necessary, however,
as most tables follow more or less a
similar approach, with bigger bonuses for
more advanced ranks, as well as more
central files, for the strong features, and
bigger penalties for less advanced ranks
and more central files, for the weak
features. This is not true in all cases, there

20
 eg values(kings are excluded from the
equation, as kings are uncapturable and do
not have a specific value, as everyone
Chapter I knows):

pawn: 95cps in the mg, 105cps in the eg

Material and major
knight: 310cps in the mg, 300cps in the eg
corrections of piece values
bishop: 320cps in the mg, 330cps in the eg

rook: 460cps in the mg, 490cps in the eg

The piece values
queen: 900cps in the mg, 950cps in the eg
Well, the piece values are certainly the
single most important evaluation feature
on the chess board. Without having General remarks concerning the piece
material piece values, it is difficult to values
evaluate anything at all, as they constitute
a very large portion of overall evaluation pawn: in distinction to what most authors
assessment. Of course, when you lose your of top chess engines believe, my
queen, the game is more or less over, but understanding is that the value of the pawn
losing even a single pawn without proper is almost the same for the mg and eg, with
compensation is also completely disastrous the eg value being a bit higher, as in the eg
with perfect play. So, having correct piece the presence of passed pawns increases the
values is quite essential to good play of probability of promotion with material
chess engines, as well as to satisfactory increment. Giving a much bigger number
human assessment of each and every chess for the eg is wrong, according to me, as the
position. side with less pawns will usually have
In the course of time, different handbooks more pieces, and having a greater number
have given different assessments of the of pieces is the better choice in the mg and
values of the pieces, which more or less eg alike.
agree in the general terms, while
sometimes disagreeing on the details. knight: well, the knight is the second-
Mine assessment will not be very much weakest piece after the pawn, and the
different from previous ones, though I will weakest non-pawn piece. The general rule
have my points of emphasis too. First of is that the knight value is bigger in the mg
all, one should mention, that all piece and lower in the eg, as the knight is a
values within any framework are much slower piece than the bishop or rook,
necessarily completely dependent on the for example, and its slowness is hidden in
rest of the evaluation factors in the the mg by the presence of more pawns that
framework, before all those concerning will deter in their movements also the rest
imbalances, various additional corrections of the pieces, but quite evident in the eg. In
of the values based on the presence of the present evaluation framework,
specific board conditions, etc. Thus, when however, the availability of additional
one looks at the concrete numbers for the correcting factors, like the distinction
specific pieces, one should also look at between a bishop and a knight with pawns
those additional correcting factors. on both wings of the board, renders the
Within my evaluation framework, the difference between the mg and eg numbers
different pieces have the following mg and quite small.

21
bishop: it is a general misconception, Piece square tables
frequently repeated in various handbooks,
that the values of the bishop and knight are Piece square tables(psqt), as widely
almost equal. Of course, this is not the implemented in most chess engines, and
case at all. There is a, quite substantial, mentally used to much benefit by all
distinction between the strength of the strong chess players, represent the most
bishop and that of the knight. In fact, the obvious and significant correction of the
bishop is a much stronger piece, both in plain piece values, based on the easy-to-
the mg and eg. Although in the mg the make observation that the relative strength
values are close, the bishop always of each and every piece changes
remains stronger, as otherwise not keeping depending on the specific square that piece
one's bishop in the mg will also result in resides on.
not having it in the eg. The difference in The self-evident chess knowledge
strength increases in the eg, where the principles mirrored in the particular psqts
bishop moves around much faster. largely reflect 3 basic and very valid
observations:
rook: in my understanding, the rook value - pieces in general do gain in value closer
measures around one and a half times the to the center of the board
average value of the 2 minor pieces. The - pieces in general do gain in value on
basic rule is that the rook value increases more advanced ranks
measurably in the eg, on a par with its - concerning only the king, kings do gain
increased mobility. In the mg, the rook value closer to the edges of the board on
movements are thwarted by the presence less advanced ranks in the mg, and do gain
of more pawns. in value, quite the opposite, in the center
and on more advanced ranks in the eg
queen: here again, I will agree with most
writers, that the queen value roughly Below we will take a brief look at the
equals 2 rooks. Most recognisable queen separate psqts.
value rule is that the queen value gets
significantly higher in the eg, where its king psqt: as said, the king gains value
movements are freer in comparison to closer to the edges of the board, especially
earlier stages of the game. Different the 2 corners, on less advanced ranks, in
imbalances significantly correct the ad-hoc the mg, and gains value in the center of the
value. board and on more advanced ranks in the
eg. The reason for this is simple:
Note: please, bear in mind, that above- - king should be kept in the edges and
cited piece values are only meant as a corners on lower ranks in the mg, as there
general assessment rule for human enemy pieces' attacks are significantly less
consumption. What concerns engines, the frequent than in the center and on higher
above values, in significant agreement ranks, already in the lion's den
with numbers found by a range of leading - king should go towards the center of the
engines through exhaustive testing, should board and on higher ranks in the eg, as in
be adjusted accordingly, basically meaning the eg enemy piece attacks are
that, due to the presence within any significantly less dangerous, due to the
elaborated evaluation framework of a smaller number of pieces, while the king
whole lot of particular pawn and minor itself is able to provide assistance to own
piece features, the values of the minor passers in their march to promotion,
pieces should be increased by some 30% successfully attack enemy pawns, restrict
over the above-cited ad-hoc values, while the enemy king activity, as well as quickly
those of the major pieces by some 50%. switch from one side of the board to

22
another on such squares, which is undefended pawn, an isolated pawn, etc.,
important, especially for such a very-slow- etc., etc. Similarly, a g2 pawn, for
moving piece, as the king example, can also be most of the above,
plus a valuable king shelter pawn.
As both above-mentioned reasons are very
weighty, the king psqt values should be
very significant too. 8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 25 35 45 55 55 45 35 25
8 -170 -180 -190 -200 -200 -190 -180 -170 5 17 25 33 50 50 33 25 17
7 -130 -140 -150 -170 -170 -150 -140 -130 4 13 17 30 45 45 30 17 13
6 -120 -130 -140 -150 -150 -140 -130 -120 3 7 10 13 20 20 13 10 7
5 -80 -90 -100 -120 -120 -100 -90 -80 2 5 7 10 13 13 10 7 5
4 -30 -40 -60 -80 -80 -60 -40 -30 1 0 0 0 0 0 0 0 0
3 30 10 0 -20 -20 0 10 30 a b c d e f g h
2 90 100 70 50 50 70 100 90
1 100 120 80 60 60 80 120 100 pawn psqt(mg)
a b c d e f g h

8 0 0 0 0 0 0 0 0
king psqt(mg) 7 0 0 0 0 0 0 0 0
6 35 45 55 65 65 55 45 35
8 0 10 20 30 30 20 10 0
5 25 33 42 60 60 42 33 25
7 20 40 60 80 80 60 40 20
4 20 25 40 55 55 40 25 20
6 40 60 90 100 100 90 60 40
3 10 15 20 30 30 20 15 10
5 20 40 60 80 80 60 40 20
2 7 10 15 20 20 15 10 7
4 -20 20 50 70 70 50 20 -20
1 0 0 0 0 0 0 0 0
3 -35 0 20 40 40 20 0 -35
a b c d e f g h
2 -40 -30 -10 0 0 -10 -30 -40
1 -50 -40 -30 -20 -20 -30 -40 -50
a b c d e f g h pawn psqt(eg)

king psqt(eg) knight psqt: knight psqt is doubtless the

second most important psqt after king psqt.
pawn psqt: pawn psqt is essential, though Reason for this is that the knight is a slow-
it is to be remarked that pawn psqt is moving piece, it takes time to go from one
probably the most unreliable table one can square to another, so the particular square
find out there, as it is dependent on the the knight currently resides upon takes
factoring in of so many other possible much greater significance. Hence, the
pawn features, that should also ideally values for the knight psqt should
have their psqts, that its numbers get to a necessarily be quite big.
big extent a matter of pure convention. Main knight psqt features:
One should never look at the pawn psqt - it is extremely important for the knight to
table without also looking at the rest of the take the central squares of the board, much
available pawn features within a particular more so than for any other non-king and
evaluation framework. non-pawn piece
Main rule of thumb is that central files and - taking edge squares, and especially
advanced ranks are bonised, but go corner squares, is extremely detrimental,
figuring out the precise values, even with as the slow-mover will need quite some
the help of a computer, given that an moves until it reaches a better position
advanced pawn on e5, for example, can - taking advanced ranks is always a good
simultaneously be a storming pawn, a choice, as it takes time to go there, and a
passed pawn, a defended pawn, an

23
retreat will only partially worsen the advanced squares are preferable for the
present knight condition bishop too.

An important remark is that knight psqt is Bishop psqt is also redundant, at least to
redundant too, at least to knight outpost some bishop outpost features.
features, so one must very carefully check
both feature numbers.
8 -10 -5 0 5 5 0 -5 -10
7 0 20 25 30 30 25 20 0
8 10 20 30 40 40 30 20 10 6 25 28 45 55 55 45 28 25
7 20 30 40 50 50 40 30 20 5 20 30 40 50 50 40 30 20
6 27 55 68 80 80 68 55 27 4 7 20 25 40 40 25 20 7
5 20 30 40 50 50 40 30 20 3 0 13 20 25 25 20 13 0
4 7 20 35 40 40 35 20 7 2 -7 0 7 13 13 7 0 -7
3 -7 7 20 27 27 20 7 -7 1 -13 -7 0 7 7 0 -7 -13
2 -13 -7 0 7 7 0 -7 -13 a b c d e f g h
1 -30 -20 -13 -7 -7 -13 -20 -30
a b c d e f g h bishop psqt(mg)

knight psqt(mg) 8 -15 -10 -5 0 0 -5 -10 -15

7 0 13 17 22 22 17 13 0
8 -10 0 10 20 20 10 0 -10 6 25 28 70 80 80 70 28 25
7 10 18 25 33 33 25 18 10 5 20 30 60 70 70 60 30 20
6 27 55 100 120 120 100 55 27 4 10 30 40 60 60 40 30 10
5 20 30 60 70 70 60 30 20 3 0 20 30 40 40 30 20 0
4 10 30 50 60 60 50 30 10 2 -10 0 10 20 20 10 0 -10
3 -10 10 30 40 40 30 10 -10 1 -20 -10 0 10 10 0 -10 -20
2 -20 -10 0 10 10 0 -10 -20 a b c d e f g h
1 -40 -30 -20 -10 -10 -20 -30 -40
a b c d e f g h bishop psqt(eg)

knight psqt(eg) rook psqt: rook psqt is far less important

than psqts for the minor pieces, reason
bishop psqt: bishop psqt is less important being the fast-moving nature of the rook,
than knight psqt, but still an important one. which makes the current square, occupied
The rules for assigning values for by the rook, far less significant. Another
particular squares pretty much follow reason is that rooks are much easier to
those for the knight, with the major evict from a particular square than minors,
distinction being that the bishop feels less by pawn and minor threats alike,
awkward on edge files and ranks, because relativising thus residence.
it can leave them much quicker than the Main rules:
knight, and besides, while being a sliding, - central files are important, it is easier to
long-range piece, the bishop is able to move around from the center, but this is
exert considerable pressure, attack further associated with attacks upon enemy
particular squares on the board, the enemy objects in the center, as well as the center
king shelter, etc., even from squares far itself
removed from the focal point. So, for - more advanced ranks are important, but
example, a white bishop on c1, while only relatively, under a lot of caveats, as
sticking to its home edge square, can very on more advanced ranks the enemy pieces
successfully attack the h6 square of the usually have better control; on more
black king shelter. Still, central and more advanced ranks the rooks can swing from

24
one wing of the board to the other to take to more or less control all the board,
aim at enemy objects, which is rarely though on such squares enemy attacks are
possible on the 1st and 2nd ranks, with the also more likely. Whether the 7th rank,
presence of lots of own pawns possibly other, non-central files, are
- the 7th rank is particularly important, as bonised, will depend pretty much on other
the rook is able to attack from there many existing evaluation factors, as enemy king
enemy pawns, residing on their home rank, shelter attacks, queen on open/semi-open
the enemy king shelter and, in the eg and file bonus, the particular queen mobility
mg alike, on occasion restrict the enemy definition, etc.
king to its back rank

Rook psqt is redundant with different rook 8 0 0 0 0 0 0 0 0

attacking features, possible rook outposts, 7 0 0 0 0 0 0 0 0
etc. 6 0 0 13 20 20 13 0 0
5 0 0 20 25 25 20 0 0
4 0 0 20 25 25 20 0 0
8 5 15 35 45 45 35 15 5 3 0 0 13 20 20 13 0 0
7 25 35 40 50 50 40 35 25 2 0 0 0 0 0 0 0 0
6 5 15 35 45 45 35 15 5 1 0 0 0 0 0 0 0 0
5 0 10 30 40 40 30 10 0 a b c d e f g h
4 -5 5 25 35 35 25 5 -5
3 -10 0 20 30 30 20 0 -10 queen psqt(mg)
2 -15 -5 15 25 25 15 -5 -15
1 -20 -10 10 20 20 10 -10 -20 8 0 0 0 0 0 0 0 0
a b c d e f g h 7 0 0 0 0 0 0 0 0
6 0 0 20 30 30 20 0 0
rook psqt(mg) 5 0 0 30 40 40 30 0 0
4 0 0 30 40 40 30 0 0
8 3 10 22 27 27 22 10 3 3 0 0 20 30 30 20 0 0
7 17 22 25 30 30 25 22 17 2 0 0 0 0 0 0 0 0
6 3 10 22 27 27 22 10 3 1 0 0 0 0 0 0 0 0
5 0 7 20 25 25 20 7 0 a b c d e f g h
4 -3 3 17 22 22 17 3 -3
3 -7 0 13 20 20 13 0 -7 queen psqt(eg)
2 -10 -3 10 17 17 10 -3 -10
1 -13 -7 7 13 13 7 -7 -13
a b c d e f g h Pawns on squares the colour of the own
bishop
rook psqt(eg)
Definition: any pawn placed on a square
queen psqt: queen psqt is the least the colour of an existing own bishop
significant psqt. Reason: queen is able to
move around very fast, attack enemy Note: the term will be considered even
objects from afar, which pretty much when one side has more than one bishop
relativises its place on the board, but also
for the fact that on more advanced squares, Value: penalty, -8cps in the mg, -15cps in
as well in the center, the queen is easier to the eg, for any such pawn
evict by practically all enemy non-queen
pieces than any other piece. Additional information: this is one of the
For queen psqt, occupying central squares most valid chess terms. The penalty is
is justified, as from there the queen is able obviously due for a variety of reasons:

25
- with own pawns on squares the colour of The eg penalties are much bigger for the
the bishop, the chance that enemy pawns simple fact that, with decreasing board
are on squares of opposite colour, not the material, the weakness will severely grow,
colour of the bishop, increases, meaning as other factors, giving variety to the
that the enemy, whether it has bishop or game, will start disappearing, and the
knight for the imbalance, will be able to attackable pawns become more salient.
effectively target and attack those pawns,
while the own bishop itself will not be able Frequency: very frequent
to do so
- as there is nothing to potentially
compensate for the above-mentioned Specific conditions amplifying or
severe condition, it will usually be long- changing the weakness
term and acquire much more positional
outlines Those are plentiful and very important.
- having a single non-compensatable
liability will certainly render more
awkward the rest of the own forces, while Blocked pawns on squares the colour of
boost the performance of enemy forces, for the bishop
the simple fact that such pawns should be
defended somehow Definition: pawns, blocked by enemy
pawns on squares the colour of the bishop

Value: additional penalty, -10cps, both for

the mg and eg

Additional information: the over-penalty

is due because:
- the condition of being blocked makes the
pawns fixed targets, unable to move; fixed
targets are easier to attack and destroy
- blocked in general represents a more
durable condition, further highlighting the
weakness

almost all white pawns are on squares the

colour of the own bishop, except for the f3
pawn. In this way, the g3 pawn is already
directly attacked, while the h4,e3,a3 and
b2 pawns potentially attackable.
None of the black pawns are on squares
the colour of the d6 black bishop, so not
directly attacked or potentially attackable
by the opponent bishop.
Above condition will also tie other white
pieces to the defence of the pawns, and
naturally give more freedom to the rest of
the black army.

26
with only weakness being the presence of
own blocked pawns on squares the colour
of the bishop, white feels very awkward
and black has big, winning advantage.
Thus, a single factor turns the game
around.

Frequency: very frequent

Central and semi-central blocked pawns

on squares the colour of the bishop

Definition: pawns on files c through f on

ranks 3 through 5 that are blocked by
enemy pawns on squares the colour of the
own bishop because of the central blocked d4 pawn,
the white dark-square bishop has almost
Value: additional penalties, specific for nowhere to go. His black counterpart, on
the different squares: the other hand, enjoys excellent activity.
d4 or e4 square: -20cps, both for the mg
and eg
d5 or e5 square: -10cps, both for the mg
and eg
c4 or f4 square: -8cps, both for the mg and
eg
c5 or f5 square: -5cps, both for the mg and
eg
d3 or e3 square: -6cps, both for the mg and
eg
c3 or f3 square: -3cps, both for the mg and
eg

Additional information: the more central

the blocked pawn is, the higher the over-
penalty, because:
- a more central pawn will have bigger
influence on events on different parts of less central blocked pawns are way less
the board negative, but also represent a significant
- a more central pawn is an easier target, liability. The d5 and c4 blocked white
more open to attacks pawns render the white light-square bishop
- critically, on a range of occasions, the extremely awkward.
more centrally-placed pawn will largely
paralyse the movements of the own Frequency: frequent
bishop, as most of the traffic naturally
goes through the center, and compromise
the activity of other friendly pieces

27
Central d4/e4 isolated pawn, blocked by Frequency: infrequent
an enemy minor outpost

Definition: central d4 or e4 pawn, that is d3/e3 twice backward pawn on square

isolated and blocked by an enemy minor the colour of the bishop
piece outpost, knight or bishop, on square
the colour of the own bishop Definition: twice backward pawn on d3 or
e3, whether opposed or unopposed one, on
Value: additional penalty, -15cps, both for square the colour of the bishop
the mg and eg
Value: additional penalty, -12cps, both for
Additional information: the over-penalty the mg and eg
is due because:
- this very much simulates the condition of Additional information: the over-penalty
a blocked central d4/e4 pawn, reining in is due because:
the own bishop's activity - this will severely paralyse the own
- the pawn is still fixed and easier target bishop, with the twice backward pawn
- the enemy minor piece outpost will be taking a very central place
excellently placed, combining a range of - as the twice backward pawn will presume
functions the presence of 2 other own pawns,
- finally, the blocker itself is not static, blocked on same colour squares, central at
which allows for other enemy pieces to that, the negative effect will spread over
take its place, simultaneously blocking and the entire board, often deactivating
attacking the pawn additional own pieces apart from the
bishop

the black knight on d5 effectively blocks

the white d4 pawn on square the colour of as easily seen, the white e3 twice
the white dark-square bishop. The white backward pawn, blocked on square the
bishop has severe movement restrictions, colour of the bishop, represents a major
looking pitiful, the d4 pawn is immobile liability. Apart from very successfully
and, additionally, the place of the knight simulating blocked condition, full
can be taken successfully, after a walk to immobilisation, it also reins in not only the
the center, by the black king, which will white dark-square bishop, but the rook on
start attacking the pawn. a1 too.

28
Frequency: infrequent well, this is a much more severe condition
than otherwise. Black will be able to win
the game with far less effort than if it had a
Special rule for the imbalance knight vs dark-square bishop instead of the knight.
bishop
Frequency: infrequent
Definition: one side having just a single
knight, and the other just a single bishop
Special rule with bishop on more
Value: additional penalty, -7cps, both for advanced ranks
the mg and eg, for each pawn, blocked by
an enemy pawn on square the colour of the Definition: bishop on ranks 5 through 8 in
bishop the enemy half of the board

Additional information: this represents a Value: in case the bishop is on ranks 5

very peculiar case. through 8 in the enemy half of the board,
The over-penalty is due because: all associated penalties for the presence of
- in distinction to an own bishop, the own pawns on squares the colour of the
knight will also be able to attack enemy bishop will be considered in half.
pawns on squares of both colours The rule will be valid just for the mg.
- the knight itself, when placed on squares
opposite the colour of the enemy bishop, Additional information: the halving of
will remain invulnerable the penalties is due to the fact that an
- the possibility of exchanging bishop and advanced bishop will:
getting rid of the weakness is much lower, - either frequently be easier to exchange,
as this could happen only on squares the so the penalties will become irrelevant
colour of the bishop, and, as a general rule, - or, sufficiently well-placed, maybe
statistically it is more difficult to trade outposted or even attacking the enemy
pieces of different power king shelter, so that the own pawns on
- occasionally, the knight could become a same colour will mostly influence its play
good blocker of enemy pawns, in no way at all
highlighting their weakness
Still, some penalisation should remain, as
returning to less advanced ranks within the
limits of the larger structures of own
pawns is a possibility to be reckoned with
under specific circumstances.

29
 the rule, rather than exception, in that stage
of the game.

Frequency: frequent

Knight with blocked pawns

Definition: bonus for each knight for the

number of blocked pawns on the board

what should the g5 bishop be penalised

for, when it is easy to exchange it?

the knight will get bonus for the

a5,c6,e4,f5 and h4 blocked pawns

Value: bonus, equal for mg and eg,

specific for the different files in terms of
centralisation:

central e or d files: 10cps

or, the nicely posted bishop on h6, semi-central f or c files: 7cps
attacking the black king shelter? The g or b files: 4cps
pawns on same colour have almost no h or a edge files: 2cps
influence on its play.
Additional information: the bonus is due
This condition is a bit difficult to for the better relative performance of
understand for engines, which frequently knights in positions with blocked pawns.
underestimate it. Positions with blocked pawns are actually
closed positions, contrary to the belief that
The eg penalty should remain in full force, closed positions are positions with large
due to the fact that endgame exchanges are number of pawns, no matter their essence,
far less common, bishops would rarely be present.
gorgeously placed on advanced ranks in A position starts being closed, only when a
the eg, and besides, crossing the entire bigger number of pawns get blocked by
board, spanning own and enemy halves, is enemy pawns. Until that time, regardless

30
of the quantity of pawns, a position is still condition of more blocked pawns present,
not a closed one. so that knights will gain in value relatively
to them.
It is not that much that the knights get
stronger, rather that the bishops get
weaker.

For the closedness of the position, central

blocked pawns play a bigger role, of
course, and that is why they get the larger
bonus.

this one is not a closed one, although all

pawns are present. It might be closed later
though.

knights feel much more comfortable with

larger number of blocked pawns present,
especially central ones. As easily seen
above, both black bishops feel very
awkward, stopped in their movements by
own and enemy pawns alike. The bishop
on c6 is stopped by the own d5 and b5
blocked pawns, so it can move only on less
advanced ranks. His counterpart on e7 is
completely stopped by the enemy blocked
pawns on b4,d4,e5, plus the pawn on f4.
that one, quite the contrary, is already The white bishop is also stopped in its
closed. Pawns blocking each other ensure movements by the enemy blocked pawns
closedness. on b5,c4,d5 and e6. That is certainly not
true for the white knight on f3, though.
Knights perform better relative to, for Although it can not currently do a very
example, bishops, as that will be the most useful job, with own d4 and e5 blocked
common imbalance, for the simple reason pawns in its way, it can slow-jump its way
that bishops, as sliding, long-range pieces, around to a better position, after for
accustomed to quickly moving around the example, Nf3-d2-f1-g3-h5. That
entire board with single long moves, will manoeuvre takes time, but is certainly
be severely thwarted by the closed doable. It is very difficult for the bishops,

31
on the other hand, to improve, so that for
them that is more or less a permanent
condition.
That is why knights always prefer
positions of a more closed nature.

well, we have this condition now: no

pawns on the central e and d files, at least
one white pawn on the queen wing, and at
least one white pawn on the king wing

Value: bonus, 30cps in the mg, 50cps in

with more knights present, of course, both the eg
of them will get the bonus
Additional information: The bonus is due
Frequency: frequent for the obvious reason the bishop will be
able to perform better than the knight with
play on both wings of the board and no
Bishop vs knight with pawns on both central pawns thwarting its movements.
wings More specifically, the bonus is dispensed
because:
Definition: one side having exactly one - the bishop takes just one move to go
bishop, and the other side exactly one from one flank to the other, the knight in
knight, with the bishop side having at least comparison will need 2 or 3 for the same
one pawn on the queen wing, a or b files, feat
and at least one pawn on the king wing, h - the bishop is able to simultaneously
or g files, and no either own or enemy attack enemy pawns on one wing, and
pawns present on central e and d files defend own pawns on the other, something
the knight certainly can not do
- with passed pawns present, the bishop
will be able to simultaneously support the
advance of the own passers on one wing,
and stop the advance of enemy passers on
the other wing, by just taking, for example,
a comfortable long diagonal; such tasks
are far from feasible for the slow-moving
knight

32
 Frequency: frequent

Chapter II

Mobility

Mobility is one of the most important

evaluation elements in chess. Actually, the
power of the different pieces themselves is
derived from their mobility on an empty
board. On a non-empty board, mobility
the white bishop simultaneously attacks will define the real power of chess pieces
the enemy b6 pawn and defends the within the existing specific circumstances.
friendly g3 one, ensuring white big Sometimes, high mobility pieces of lower
advantage. power may prove stronger than low
The black knight can do nothing similar. mobility pieces of higher power. A low
mobility queen might be weaker than even
a well-placed, high mobility knight or
bishop.
Mobility is equally important for all
pieces, but different pieces have separate
mobility definitions, as well as mobility
values. The lower the power of the piece,
the less squares usually it has access to and
consequently the more important their
relative value is. Thus, the knight enjoys
biggest mobility numbers, followed by the
bishop, rook and queen.
King and pawn mobility stand apart and
will be discussed separately.
Within our framework, accessible mobile
squares will be psqtised for the entire
board. I guess this is necessary to do, as
the white bishop on c6 simultaneously different squares of the board have
supports the advance of the friendly passer different importance for each specific
on a5 and stops the advance of the enemy piece. For example, the knight will strive
passer on g3. towards the center of the board and
The slow-moving black knight can only do advanced ranks, where it could be
one task at a time. outposted, same more or less goes true for
the bishop, the rook will find central files
The eg bonus is much larger, as in the eg and advanced ranks, the 7th rank, etc.
the bishop movements are likely to be less more suitable, while the queen will prefer
burdensome because of the lower number the center of the board, as well as more
of pawns. advanced ranks.

33
 Knight mobility 8 12 13 14 15 15 14 13 12
7 16 17 18 19 19 18 17 16
Definition: any empty square on the board 6 20 28 30 32 32 30 28 20
that is not attacked by an enemy pawn, 5 18 26 28 30 30 28 26 18
plus any board square occupied by an 4 16 24 26 28 28 26 24 16
enemy piece or pawn which are not 3 14 20 22 24 24 22 20 14
defended by another enemy pawn or piece, 2 12 13 14 15 15 14 13 12
plus any board square occupied by an 1 10 11 12 13 13 12 11 10
a b c d e f g h
enemy bishop, rook or queen, which are
defended by an enemy pawn or piece
knight mobility psqt(mg)

8 10 11 12 13 13 12 11 10
7 12 13 14 15 15 14 13 12
6 12 17 22 24 24 22 17 12
5 16 24 28 30 30 28 24 16
4 16 24 28 30 30 28 24 16
3 14 20 22 24 24 22 20 14
2 12 13 14 15 15 14 13 12
1 10 11 12 13 13 12 11 10
a b c d e f g h

knight mobility psqt(eg)

Additional information: knight mobility

is due the highest values of all pieces,
because the knight by its nature usually
accesses the smallest number of squares.
c2,e2,f3 and e6 are mobile squares for the Its values tend to somewhat increase for
knight, as they are empty and not attacked specific central squares in the eg, where
by an enemy pawn. c6 is also a mobile the knight should be excellently placed,
square, as it is taken by an enemy pawn and decrease for more advanced ranks, due
which is not defended by any enemy pawn to the declining importance of outposts.
or piece. f5 is a mobile square, too, as,
although it is attacked by an enemy pawn, Frequency: an all-frequent factor, there is
it is taken by an enemy rook. b3, on the not a piece on the board lacking mobility,
other hand, is not a mobile square for the even if it is zero
knight, as it is attacked by the a4 enemy
pawn.
Bishop mobility
Value: bonus, valid in terms of psqt
Definition: any empty square on the board
that is not attacked by an enemy pawn,
plus any board square occupied by an
enemy piece or pawn which are not
defended by another enemy pawn or piece,
plus any board square occupied by an
enemy knight, rook or queen, which are
defended by an enemy pawn or piece

34
 8 8 9 10 11 11 10 9 8
7 10 11 12 13 13 12 11 10
6 12 17 18 21 21 18 17 12
5 15 22 25 26 26 25 22 15
4 14 21 25 26 26 25 21 14
3 12 17 18 21 21 18 17 12
2 10 11 12 13 13 12 11 10
1 8 9 10 11 11 10 9 8
a b c d e f g h

bishop mobility psqt(eg)

Additional information: bishop mobility

deserves lower values than knight
mobility, though relatively high ones in
comparison to other pieces. Its values,
similarly to the knight, tend to increase for
c4 is a mobile square for the white bishop,
certain central squares in the eg, while
as it is empty and not attacked by an
decreasing for more advanced ranks, due
enemy pawn. a6 is also a mobile square, as
to the smaller importance of outposts.
there is an enemy knight, albeit defended
by an enemy rook. e4,b5 and c2 are not
Frequency: again, as with the knight, all-
mobile squares, as they are empty and
frequent
attacked by enemy pawns. f5 is not a
mobile square, as it is not empty and
attacked by an enemy pawn. Finally, e2
Rook mobility
and b1 are also not mobile squares for the
bishop, as being occupied by own pieces.
Definition: any empty square on the board
that is not attacked by an enemy pawn,
Value: bonus, valid in terms of psqt
plus any board square occupied by an
enemy piece or pawn which are not
8 10 11 12 13 13 12 11 10
defended by another enemy pawn or piece,
7 14 15 16 17 17 16 15 14
plus any board square occupied by an
6 17 25 27 28 28 27 25 17 enemy rook or queen, which are defended
5 16 23 25 26 26 25 23 16 by an enemy pawn or piece
4 14 21 23 25 25 23 21 14
3 12 17 18 21 21 18 17 12
2 10 11 12 13 13 12 11 10
1 8 9 10 11 11 10 9 8
a b c d e f g h

bishop mobility psqt(mg)

35
 Queen mobility
c4,c5 and e3 are mobile squares for the
white rook, as they are empty and not Definition: any empty square on the board
attacked by enemy pawns. g3 is also a that is not attacked by an enemy pawn,
mobile square, as there is an enemy piece knight, bishop or rook, plus any board
which is undefended. c6 is another mobile square occupied by an enemy piece or
square, as, although attacked by an enemy pawn which are not defended by another
pawn, it is occupied by an enemy rook. d3 enemy pawn or piece, plus any board
and f3 are not mobile squares, because square occupied by an enemy queen,
they are under attack of the enemy e4 which is defended by an enemy pawn or
pawn. c2 and b3 are not mobile squares for piece
the white rook, too, as occupied by own
knight and pawn

Value: bonus, valid in terms of psqt

8 11 12 13 14 14 13 12 11
7 15 16 17 18 18 17 16 15
6 13 14 15 16 16 15 14 13
5 11 12 13 14 14 13 12 11
4 9 10 11 12 12 11 10 9
3 7 8 9 10 10 9 8 7
2 5 6 7 8 8 7 6 5
1 4 5 6 7 7 6 5 4
a b c d e f g h

rook mobility psqt(mg)

a1,b1,c1,c2,c3 and b5 are mobile squares
8 6 7 8 9 9 8 7 6
for the white queen, as they are empty and
7 10 11 12 13 13 12 11 10
9 10 11 12 12 11 10 9
not attacked by enemy pawns. b6 is also a
6
5 11 12 13 14 14 13 12 11
mobile square, as there is an enemy
4 9 10 11 12 12 11 10 9
undefended pawn. b4,d4 and e5 are not
3 7 8 9 10 10 9 8 7 mobile squares, as they are empty and
2 5 6 7 8 8 7 6 5 attacked by enemy pawns. f6 is not a
1 4 5 6 7 7 6 5 4 mobile square, as it is occupied by an
a b c d e f g h enemy pawn which is defended by an
enemy knight. a2 is not mobile square, as
rook mobility psqt(eg) under attack by the black bishop on f7. b3
is not mobile square, as under attack by the
Additional information: rook mobility black bishop and knight. d2 is also not
deserves far lower values than mobility for mobile, as the black rook on d8 attacks it.
minor pieces. Its values tend to decrease Finally, a3 and e2 are not mobile squares,
for advanced ranks in the eg, due to the as occupied by own pawn and bishop.
fact that attackable enemy objects on those
ranks are less frequent in the eg. Value: bonus, valid in terms of psqt

Frequency: all-frequent

36
 8 3 3 3 4 4 3 3 3
7 5 5 5 6 6 5 5 5
6 6 7 7 8 8 7 7 6
5 5 6 6 7 7 6 6 5
4 4 5 5 6 6 5 5 4
3 3 4 5 5 5 5 4 3
2 2 3 3 4 4 3 3 2
1 2 3 3 4 4 3 3 2
a b c d e f g h

queen mobility psqt(mg)

8 2 3 3 4 4 3 3 2
7 3 3 3 4 4 3 3 3
6 6 6 6 7 7 6 6 6
5 5 6 6 7 7 6 6 5
4 4 5 5 6 6 5 5 4
3 3 4 5 5 5 5 4 3 h1 is a mobile square for the white king, as
2 2 3 3 4 4 3 3 2 well as f1, one is free and the second one
1 2 3 3 4 4 3 3 2 taken by an enemy piece, though both
a b c d e f g h squares are not attacked by enemy pieces.
h2 is not mobile for the king, as it is under
queen mobility psqt(eg) attack by enemy knight on f1 and bishop
on e5. f2 and g2 are also not mobile, as
Additional information: queen mobility taken by own pawn and bishop.
has the lowest values of all pieces, which
slightly decrease for certain squares on Value: small bonus, 2cps in the mg, 5cps
more advanced ranks in the eg, due to in the eg
lesser importance of attacks upon enemy
objects Additional information: king mobility is
relatively unimportant in the mg. Reason
Frequency: all-frequent for this is that it is actually very difficult to
make sense when it is good to have more
free available squares, and when not. For
King mobility example, having a lot of free squares
around the king might simply mean that
Definition: any board square, be it free or the king has no or very limited pawn
occupied by an enemy pawn or piece, if shelter. On the other hand, even if it has no
not attacked by any enemy pawn or piece, or just a single available mobile square, it
including the king might be still very well sheltered by own
minor and other pieces. Sometimes, it is
good to have more square freedom, at
other times not, and at still other times this
is pretty much irrelevant. Still, a bit of
freedom is always appreciated.
In the eg, quite the opposite, more king
mobility frequently means more active
king, so it is only to be encouraged there.

37
 Pawn mobility

Pawn mobility stands quite apart from the

rest of mobility definitions and that
follows from the nature of the pawn.
Generally, pawns are mobile, able to do a
legal move, whenever they are able to
either capture diagonally any enemy pawn
or piece, or advance one or 2 squares
vertically. As diagonal pawn captures are
identical with levering, while diagonal
non-pawn captures with existing threats
upon enemy pieces, here we will be
concerned with just possible vertical pawn
advances. It is to be acknowledged that not
all available pawn pushes are equally
the white king has a lot of available mobile significant. Pushes to the 3rd and 4th ranks
squares, but is unsheltered. The black king are mostly lacking any real value, unless
almost has no free mobile squares, but is done under special conditions, for example
very well sheltered. when done to attack an enemy piece, or
when such a push would be a double pawn
push from the 2nd to the 4th rank. Thus,
within our evaluation framework, we will
concentrate on just available pawn pushes
on advanced ranks, starting from the 5th
and ending with the 8th rank.
Pawn mobility here will include mobility
of just about any pawn, be it a passer, a
storming pawn, or any other featurable
pawn. This will be a bit redundant, at least
to unblocked storming pawns, but very
consistent at the same time, as most pawn
pushes, no matter the specific nature of the
pawn, do enjoy quite similar values.

Value: bonus, valid in terms of psqt

in the eg, higher mobility is often

synonymous with improved activity. As 8 23 28 30 35 35 30 28 23
easily recognised above, the black king on 7 14 17 19 22 22 19 17 14
the edge has just 2 available mobile 6 5 8 10 12 12 10 8 5
squares, while its white counterpart enjoys 5 2 3 5 7 7 5 3 2
the proximity of 5 such. 4 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
Frequency: all-frequent, as with other
1 0 0 0 0 0 0 0 0
pieces
a b c d e f g h

pawn mobility psqt(mg)

38
 8 25 30 32 37 37 32 30 25 relative strength, as all kinds of pawns,
7 16 19 21 24 24 21 19 16 from passers to any standard pawn, will
6 7 10 12 14 14 12 10 7 have higher influence on the game, when
5 4 5 7 9 9 7 5 4 pushed in the center. Central pushing will
4 0 0 0 0 0 0 0 0 mean the possibility of creating an even
3 0 0 0 0 0 0 0 0 stronger central passer, opening up vital
2 0 0 0 0 0 0 0 0 lines in the center, when levering, placing
1 0 0 0 0 0 0 0 0 own pieces on advanced central squares
a b c d e f g h
with possible lever captures, central more
significant threats upon enemy pieces, etc.
pawn mobility psqt(eg) Edge or close-to-the-edge pushing, on the
other hand, unless under special
Additional information: the bonus is circumstances, will do quite the opposite.
given for the fact, that the free pawn has So, incentivising central pushes is another
more available options at its disposal, priority.
namely to move forward. By moving
forward, no matter what particular pawn it
represents, it improves its board location,
so more advanced ranks should be
incentivised.

available free pawn pushes for the d5 and

a5 passers are far from equal in
significance, for the simple fact that a
central d6 passer is immeasurably stronger
than an edge a6 one. Similarly, free
moving forward improves the location of available pushes for the plain f4 and h4
the free pawn. On the diagrammed pawns are quite different, as an f5 blocked
position, if the c6 white pawn advances, it pawn is much stronger than a h5 blocked
will become a strong passed pawn on the pawn.
7th rank, just a single square away from
promoting, if the a5 pawn is pushed, it will
become a very strong blocked pawn on the
6th rank, and, if the e4 pawn is moved, it
will start levering on the 5th rank.

Apart from vertical advancement, it is very

important for free pawns to be more
centrally placed in terms of files. The more
central a free pawn is, the bigger its

39
 Additional information: the extremely-
well deserved bonus is due for the
following reasons:
- such a pawn can quickly advance, taking
central position and starting influencing
the center
- in case it is on a file on the side where
the enemy king is, it can quickly advance
to the 4th rank and start exerting pressure
upon the king as a storming pawn, also
threatening with further advance

As both random central pawns and

storming pawns are extremely important,
the condition can hardly be overestimated.

an e5 lever push will open the central e Please note, that this is very much
file, a b5 lever push, on the other hand, different from simply having a central
will activate simply developments along pawn on the 2nd rank, as such a pawn
the much less significant b file might be more or less immobile.

Frequency: very frequent

Available double pawn pushes

Definition: pawn on the 2nd rank on file

c,d,e or f, with the squares in front of it on
the 3rd and 4th ranks both free

the conditions of the c2 and f2 central

pawns are quite different. While the c2
pawn can immediately advance with a
double push to c4, in order for the f2 pawn
to have this opportunity, first the white
knight on f3 should go somewhere, even if
modestly retreating on e1. That is why
retreats are not always necessarily bad.

the d2 pawn represents this condition, it

has an available double pawn push

Value: small bonus, 8cps, just for the mg

40
 piece less is not easy, is it? Not to mention
possible long-term conditions.

Low mobility pieces on the edge

Definition: any non-pawn and non-king

piece on the edge of the board, either the h
or a files, or the 1st or 8th ranks, having
just a single available mobile square

Value: penalty, -20cps, both for the mg

and eg

Additional information: as said, low

mobility pieces provide this side with
guess what the best move in this position fewer assets in a competitive environment.
is? Right, Ne1, threatening f2-f4. The outlook might not be utterly dismal, as
the piece is still a bit mobile, and from the
Frequency: frequent next mobile square it might find itself even
more at ease, but the situation is to be
avoided, whenever possible.
Low and zero mobility pieces

Low and zero mobility pieces are very

important in chess, though seemingly, not
all humans, and very few, even top
programs, will be able to even partially
make sense of them. Being low-mobile, of
course, means being less active, at least
currently, sometimes even long-term. Less
activity, of even a single piece, is always
to be avoided, as, in the struggle for
supremacy, every single asset matters. The
higher mobility of other pieces is not a
guarantee that everything is fine, so that,
apart from scoring general mobility as a
sum for all pieces, taking into account
singular piece mobility characteristics is a
must. Occasions, when a single, badly- the white bishop on c1 is a low-mobility
placed piece loses the game, are far from piece on the edge, as well as the black
rare. bishop on a2. Such pieces are easier to
The situation is even worse, when a certain attack, and sometimes even trap.
piece is a zero-mobility one, i.e. it has no
available free mobile squares at its
disposal at all. In such cases, the side
having this negative, will mostly be
playing with a piece less, albeit only for a
limited period of time. Playing with a

41
the rook on a1 is a low-mobility piece, b1 the knight on h4 and the rook on a6 are
being its only accessible square, the knight zero mobility pieces. They feel quite
on h7, although well-placed and attacking awkward, can not transfer to other parts of
the enemy king shelter, is also a low- the board, if needed, are easily attackable
mobility piece on the edge, vulnerable to and frequently trappable. Whether the
attacks and capturing, with f8 being its condition will be more or less permanent
only accessible square will largely depend on particular board
factors.

Zero mobility pieces on the edge

Definition: any non-pawn and non-king

piece on the edge of the board, either the h
or a files, or the 1st or 8th ranks, lacking
even a single available mobile square

Value: penalty, -40cps, both for the mg

and eg

Additional information: as noted, zero

mobility is tantamount to playing without
a piece, either short- or long-term. That is
very negative, and sometimes even loses
the entire game. With no additional
specific conditions mentioned, the
supposition will be that zero mobility will the white queen on h6 is trapped, and can
be just short-term, but that can in no way be captured after Bb4-f8
be guaranteed, hence the generalised
custom-assessed value. Long-term zero
mobility pieces are naturally due a
significantly bigger penalty, and we will
pay special attention to them later.

42
the white bishop on h2 is trapped, though the white knight on e5, even though
not permanently. After Ng1-e2, it can excellently placed and strongly-supported,
move via g1 to freedom. as well as attacking the enemy king
shelter, is trapped, enemy pawns cut its
Frequency: frequent retreat and possible transfers to either the
king or queen side. The black bishop on e8
ensures that the knight will not be able to
Zero mobility pieces not on the edge advance, too. Thus, the knight is fully
immobile, it can not be activated on other
Definition: any non-pawn and non-king parts of the board, and that might prove
piece not on the edge of the board, on files decisive, as the focus of the game
b through g and ranks 2 through 7, lacking frequently shifts from one section to
even a single available mobile square another. The opponent side will be able to
mobilise all its pieces for different tasks,
Value: penalty, -15cps, both for the mg while the knight side will have to do
and eg without the services of the knight on a
range of occasions.
Additional information: this happens
much rarer, as in the center pieces are Frequency: infrequent
generally more mobile, due to the larger
number of squares on an empty board they
can go to from there. Still, the factor is Zero mobility king
important, as zero mobility, especially if
permanent, at least means this piece can Definition: king with no available mobile
not be transferred to other sections of the squares
board to perform different functions and
pieces are mobile for precisely this very Value: penalty, -10cps in the mg, -30cps
reason, to go around. Such pieces are also in the eg
frequently trappable.
Additional information: this is a bad
condition, though much more severe in the
eg.
In the mg, having zero mobility will
frequently mean the king is under strong

43
enemy attack, and attacks are already smothered mate also involves a zero
scored separately, but might also mean the mobility king
king enjoys good sheltering. So, no
generally valid conclusions might be
drawn, but still having a bit of freedom of
movement is to be encouraged. Zero king
mobility might also indicate impending
zugzwang.
In the eg, zero mobility is always bad, it
can either mean the king is extremely
inactive, under strong enemy attack, or
even herald zugzwang. As resources in the
eg are rather limited, the inactivity of each
and every piece is doubly important.

in the eg, zero king mobility will often

happen in one of the corners of the board
as an indication of a zugzwang

zero mobility king in the mg under severe

enemy attack

or, again in the corner, pointing at an

inability to activate. White can not save
that, simply because it plays without a
king. The black king can enjoy a very long
walk deep into the enemy camp, with the
white bishop basically shuffling around.
From afar, the win might not be
immediately obvious, unless one has good
evaluation.

Frequency: infrequent

44
 Permanently trapped minors

In distinction to low and zero mobility

pieces, that would always have very low
mobility, but are not guaranteed to be
trapped for a prolonged period of time,
permanently trapped minors might even
have better mobility, but will always
necessarily be restricted to a small portion
of the board in a longer time frame.
This space restriction, due to either
limitations imposed by enemy pawns or
own pawns, blocked by enemy ones,
basically means that this particular piece
will largely stay out of the game and will
not be transferrable to other parts of the white knight on b1, trapped by enemy
board, where it might be needed. Playing pawns
with a piece less for more than just a
couple of moves points at a sure demise Value: large penalty, -150cps, both for the
for the side yielding it. Thus, permanently mg and eg
trapped minors are a very major liability,
to be avoided whenever possible, and due Additional information: the penalty is
rather big penalties. obviously due for the permanent
It is funny how even the top engines are so placement of the knight out of the game.
often fully clueless of some of their pieces As easily seen on the diagrammed
being permanently trapped, obviously, position, all potentially available mobile
they are lacking in knowledge for this squares for the knight, a3,c3 and d2, are
specific feature. controlled by enemy pawns, and in such a
There are different types of permanently way, that one of those pawns is defended
trapped minors, below we will concentrate by the other, while the defending pawn
on the most useful and widespread will most certainly enjoy good protection,
instances. too, either by other pawns or even pieces.
Additionally, the enemy pawns are
blocked, which further restricts the knight,
White knight on b1, trapped by enemy denoting that they will be attackable by
pawns fewer own pieces.
Above conditions signify prolonged
Definition: white knight on b1, with white limitations, and that is usually the case in
pawns on c2,b3, black pawns on c3,b4, or, practice. Situations like this can happen
alternatively, on the king side, white both in the mg and eg. The fact that the
knight on g1, with white pawns on f2,g3, penalty is smaller than the material
black pawns on f3,g4 equivalent of a full piece is due to possible
knight sacrifices for one or 2 enemy
pawns.

Frequency: infrequent

45
 White knight on a1, trapped by own Frequency: infrequent
pawns

Definition: white knight on a1, with own White bishop on b1 or a2, trapped by
pawns on c2,b3, enemy pawns on c3,b4, own pawns
or, alternatively, white knight on h1, with
white pawns on f2,g3, black pawns on Definition: white bishop on b1 or a2, with
f3,g4 white pawns on c2,b3, black pawns on
c3,b4, or, alternatively on the king side,
white bishop on g1 or h2, with white
pawns on f2,g3, enemy pawns on f3,g4

white knight on a1, trapped by own pawns

Value: large penalty, -220cps, both for the

mg and eg white bishop on b1 or a2, trapped by own
pawns
Additional information: the penalty is
due for same reasons: prolonged mobility Value: large penalty, -220cps, both for the
limitations. In distinction to the case of a mg and eg
white knight trapped by enemy pawns,
here the corner knight is trapped by own Additional information: similar reasons
pawns, which only increases the negativity as for the white knight on a1, trapped by
of the phenomenon, as the enemy pawns, own pawns, apply. In a way, this is even
blocking the friendly ones and caging the more funny situation, as the bishop is not a
knight, can only be destroyed by other zero-mobility piece, it does have some
own pieces, but not by a sacrifice of the freedom of movement within its cage, at
knight itself. least a single available mobile square at
The condition is permanent for same any particular time, but that is all. The
reasons: the knight-caging pawn bishop is limited to that very restricted
construction is durable, due to the fact that section of the board. It will shuffle around
the own pawns involved in it are fixed, from one cage square to the other to its
while the enemy pawns well defended, heart's content, while battle rages on focal
with one of them by the remaining caging board points elsewhere, until finally, due
pawn, and the other either by another to insufficient resources, the friendly side
friendly pawn, or a friendly piece. loses the game.

46
Strange as it might seem to you, it is hard on c1, the very same knight will already be
to imagine how frequent such paradoxical trapped by the enemy d3 and c4 pawns
situations might arise in engine play.
Value: large penalty, -150cps, both for the
Frequency: infrequent mg and eg

Additional information: again, the reason

White knight on b1,a2,a3 or c1, trapped for the well-deserved penalty are mobility
by own and enemy pawns limitations in the long and very long term.
The knight can still go from a2 to c1, or,
Definition: white knight on b1,a2,a3 or c1, alternatively, from a3 to b1, but similar
with white pawns on d2,c3,b4, black leaps will hardly prove useful to the game
pawns on d3,c4,b5, or, alternatively on the outcome. The knight will be badly needed
king side, white knight on g1,h2,h3 or f1, somewhere else, and it will not be able to
with white pawns on e2,f3,g4, black pawns flash or even tortoise-walk there.
on e3,f4,g5 Sacrifices for one or 2 enemy pawns are
still possible, hence the pawn and a half
estimate.
This is also to be seen from time to time in
engine games, especially when a human
plays an engine, but who could vouch in
purely human games such situations are
inexisting?

Frequency: infrequent

White bishop on c1,b2 or a3, trapped by

own pawns

Definition: white bishop on c1,b2 or a3,

with white pawns on d2,c3,b4, black
pawns on d3,c4,b5, or, alternatively, white
white knight on a2, trapped by own pawns bishop on f1,g2 or h3, with white pawns
on e2,f3,g4, black pawns on e3,f4,g5

47
white bishop on g2, trapped by own pawns the b1 knight is trapped, but, what is even
more disastrous, is that it simultaneously
Value: large penalty, -220cps, both for the traps the own rook on a1. Thus, both
mg and eg pieces are out of the game. Sacs are
urgently needed, many engines will spot
Additional information: the penalty is this only too late.
due for long-term mobility limitations.
In distinction to other instances of
trappings, here the caged bishop does
really enjoy a rather spacious confinement,
whole 3 available mobile squares, and can
pseudo-slide from g2 to h3, f1 and even h1
for as long as it would not get bored,
though that will hardly save the game.
Sacs by the bishop itself are also not
possible, hence the evaluation estimate of
close to 3 full pawns(of course, other
friendly pieces can still sac for the bishop).

Frequency: infrequent

On occasions, a similarly-trapped minor

piece can simultaneously trap another one,
or even 2 other friendly pieces. This will, and what about this one? It is not exactly
of course, tremendously deteriorate the clear which of the white pieces traps the
situation, as the number of pieces out of remaining ones, but the picture is pitiful.
the game receives over-dangerous You would guess that never happens in
proportions. games? Of course it does, and even
frequently, provided the defending player
has no knowledge of similar tricks.

48
this is a real-life situation from one of my Bb7 is a self-trapped bishop
games. All too many, even very top,
engines, will consider the position as fully Value: penalty, -30cps in the mg, -20cps
equal, some even seeing black in the lead, in the eg
but the truth is, that white enjoys a
positional crush, of course. 3 black pieces Additional information: the large penalty
on the queen wing, the rook on a8, the is, of course, due for the very limited
knight on b8 and the light-square bishop mobility of the bishop, combined with the
on c8, are factually trapped, out of the permanence of the condition. As both
game and unable to support activities of pawns defending the bishop are immobile,
the own army elsewhere. With time, white it can not possibly go back, so its only
will attack on the king side, open the alternative to move somewhere is to try
position and smash the remaining black doing that via the 8th rank. The 8th rank,
forces. That takes time, possibly even though, deep into the enemy territory, will
many dozens of moves, and this might be usually be very well controlled by enemy
the reason why top engines fail to pieces, as is the case with the black rook
recognise white's decisive edge, but is on d8 above. So, in actual fact, the bishop
inevitable. is pretty much trapped, more precisely
self-trapped, as it is own pawns that
primarily limit its mobility.
Self-trapped bishop
Even top engines sometimes fail to
Definition: bishop on the 7th rank, understand such conditions. One of the
defended by 2 own pawns, both blocked most frequent instances of the
by enemy pawns phenomenon will happen with the bishop
attacking the enemy king shelter, like on
the position below:

49
 Chapter III

Pawns

Strong pawns

Aligned pawns

Definition: a pawn that has another own

pawn next to it on an adjacent file on the
same rank
the white bishop on g7 certainly looks very
strong, but that is just an optical illusion. It
is not only fully immobile, but, due to its
peculiar location, as well as the location of
the 2 own pawns defending it, the rest of
the white pieces simply does not have
access to the enemy king shelter, so
attacking it is close to impossible. Of
course, as engines are unable to see 30
moves ahead, they will generally think
white has huge advantage.

Frequency: infrequent

2 aligned pawns on b4 and c4 respectively

Value: bonus valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 66 68 72 74 74 72 68 66
6 52 54 56 58 58 56 54 52
5 30 33 36 39 39 36 33 30
4 16 18 22 24 24 22 18 16
3 7 9 11 13 13 11 9 7
2 2 4 6 8 8 6 4 2
1 0 0 0 0 0 0 0 0
a b c d e f g h

aligned pawn psqt(mg)

50
 8 0 0 0 0 0 0 0 0
7 44 45 47 49 49 47 45 44
6 35 36 37 38 38 37 36 35
5 20 21 23 25 25 23 21 20
4 11 13 15 17 17 15 13 11
3 5 6 8 9 9 8 6 5
2 2 3 4 5 5 4 3 2
1 0 0 0 0 0 0 0 0
a b c d e f g h

aligned pawn psqt(eg)

Additional information: aligned pawns

are due bonus due to the following
reasons:
- very flexible structure; if one of the
pawns moves forward, it immediately defended pawn on d5
becomes a well-connected defended pawn,
and both pawns are able to move forward Value: bonus valid in terms of psqt
- very nice square control in front of them;
cumulatively, both pawns control 4 8 0 0 0 0 0 0 0 0
consecutive squares on the upper rank 7 52 54 56 58 58 56 54 52
- if passers, in the mg and eg alike, such 6 30 33 36 39 39 36 33 30
pawns are a mighty asset, whose rush 5 16 18 22 24 24 22 18 16
towards the square of promotion is 4 7 9 11 13 13 11 9 7
extremely difficult to stop 3 2 4 6 8 8 6 4 2
2 0 0 0 0 0 0 0 0
Frequency: very frequent 1 0 0 0 0 0 0 0 0
a b c d e f g h

defended pawn psqt(mg)

Defended pawn
8 0 0 0 0 0 0 0 0
Definition: a pawn defended by an own
7 35 36 37 38 38 37 36 35
pawn
6 20 21 23 25 25 23 21 20
5 11 13 15 17 17 15 13 11
4 5 6 8 9 9 8 6 5
3 2 3 4 5 5 4 3 2
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

defended pawn psqt(eg)

Additional information: defended pawns

are due a nice bonus due to the following
factors:

51
- they are strong, it is difficult for the
opponent to capture such a pawn with a
piece
- defended pawns still represent a
connected feature, in case the pawn
defending the defended pawn moves
ahead, both pawns transform into a nice
aligned unit, powerful in all stages of the
game, especially when such pawns are
both passers

Frequency: very frequent

Distant neighbours

Definition: a pawn that has another own g4 and e4 pawns above are distant
pawn on the same rank across a file neighbours(similarly, f6 black pawn can
not realistically advance to f5 square even
with the help of the black g7 pawn)

Value: bonus valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 20 30 40 50 50 40 30 20
6 12 17 25 32 32 25 17 12
5 8 12 17 22 22 17 12 8
4 4 6 8 11 11 8 6 4
3 2 3 5 8 8 5 3 2
2 1 2 3 4 4 3 2 1
1 0 0 0 0 0 0 0 0
a b c d e f g h

distant neighbour psqt(mg)

a5 and c5 are distant neighbours
(above, those 2 pawns make the black b7 8 0 0 0 0 0 0 0 0
pawn fully backward: upon trying to move 7 10 15 20 25 25 20 15 10
forward, it simply can not, without being 6 6 8 12 16 16 12 8 6
lost) 5 4 6 8 11 11 8 6 4
4 2 3 4 5 5 4 3 2
3 2 2 3 4 4 3 2 2
2 1 2 3 4 4 3 2 1
1 0 0 0 0 0 0 0 0
a b c d e f g h
distant neighbour psqt(eg)

52
Additional information: distant
neighbours get their very well deserved
bonus in view of the following reasons:
- on upper ranks, they would make enemy
pawns backward, which is very important,
especially in the mg
- on lower ranks, they would frequently
stop enemy pawns' advance, which is
particularly relevant in the center and
when enemy pawns are storming pawns
- in their role as passers, or, at least when a
single one of them is passer, especially on
advanced and very advanced ranks, such
pawns represent a tremendous asset, as
they support each other across the file on
their way to promotion
a5 and d5 are very distant neighbours

Value: bonus valid in terms of psqt, only

mg

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 15 18 21 24 24 21 18 15
5 10 12 14 16 16 14 12 10
4 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

very distant neighbour psqt(mg)

well, imagine, c3 and e3 distant
neighbours stop the important d5-d4 black Additional information: very distant
break neighbours deserve bonus due to the
following considerations:
Frequency: frequent - as seen on the diagram, they frequently
render enemy pawns on less advanced
ranks partially backward, as usually the
Very distant neighbours squares in front of the enemy pawns will
also be controlled by own minor or other
Definition: any pawn exclusively on the pieces
5th and 6th ranks having another own - they are a nice tandem themselves, even
pawn on the same rank 2 files across without the help of other own pieces, but
with the support of own pawns; this could
potentially lead to decisive passer creation
- very dangerous as passers, too, or even
when only a single one of them is a passer,
especially when their placement is in the

53
quadrant of the enemy king, as a free 8 0 0 0 0 0 0 0 0
passer could additionally advance with a 7 0 0 0 0 0 0 0 0
check to the enemy king, gaining tempo 6 15 18 22 50 50 22 18 15
5 7 9 11 13 13 11 9 7
Frequency: infrequent 4 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
Blocked pawns 1 0 0 0 0 0 0 0 0
a b c d e f g h
Definition: a pawn with an enemy pawn
on the same file one rank in front blocked pawn psqt(mg)
(eg psqt is the same, with the only
distinction being that central d6 and e6
squares get only 30cps instead of 50cps)

Additional information: blocked pawns

perform a very wide range of roles. We
can talk about simple advanced blocked
pawns, blocked pawns when forming part
of a larger chain, blocked pawns when
being storming pawns at the same time,
blocked pawns that could transform into
an advanced passer, blocked central
wedges in the mg, blocked pawns defining
a larger blocked pawn structure/fortress,
that should increase drawing chances, etc.,
etc., etc.
(very much tempted now to say "Blocked
f4 represents a blocked pawn pawns are the soul of chess", but that
would sound familiar, would not it?)
Note: blocked pawns are useful in many
different ways, but here we are only Simple advanced blocked pawns we are
interested in the conditions when such discussing now(other roles will be
pawns would get a specific general bonus, reviewed in different sections) get their
and that would be when they are placed on bonus for the following reasons:
advanced ranks, 5th or 6th(for the 4th - being blocked means being more durable,
rank, we have evaluation symmetry, for and in this way the already existing asset
lower ranks, the bonus would become a of an advanced pawn is further amplified
penalty, basically the same as the opponent under this specific condition
getting bonus for its advanced blocked - extremely favourable to the solidity and
pawns, and there are no blocked pawns on durability of longer pawn chains,
the 7th rank) consisting of 3,4,5 and more members.
When longer pawn chains are blocked,
Value: bonus valid in terms of psqt both the restriction quality of longer chains
upon enemy pieces and their boosting
quality upon friendly pieces are
considerably amplified, frequently to an
extent entirely changing the logic of the
game.

54
- a central blocked pawn on d6 or e6 in the
mg represents an extremely powerful
central wedge, which, even if not
supported, has a tremendous influence
upon the outcome of the game, as it
basically splits the opponent half of the
board in 2 parts, which are difficult to
coordinate among and cramps the enemy
position to a very large extent, no matter
that this is just a single pawn
- if the enemy pawn blocking such a pawn
on the 6th rank is captured, or if the
blocked pawn on the 6th rank is supported
by another own pawn which is free, and
whose advance will challenge the enemy
blocked pawn, the blocked 6th-ranker will
immediately transform into a powerful with larger blocked pawn chains,
passer especially when they are central, the
quality of the game completely changes,
giving a substantial advantage to the side
with the better-placed pawn chain(in this
case the white pointed pawn chain, whose
most advanced member, the f6 pawn, is
closer to the enemy king than its
counterpart on c4(and also taking a more
advanced rank); please see Pointed chains
section)

well, advanced b6 and c5 blocked pawns

are simply more durable than if they were
not blocked; in the general case, it is more
difficult for the enemy to get access to and
get rid of them

the central d6 blocked wedge splits to

great effect the entire black position in 2

55
 black advanced lever on the 6th rank on f3,
additionally a storming pawn
(the pawn tension between the f3 and g2
pawns has the potential of opening the
enemy king position, compromising the
white pawn shelter, or at least driving a
mighty pawn wedge at its most vulnerable
place)

Note: general-purpose bonus is dispensed

in terms of psqt only for 5th and 6th ranks.
While this general bonus is the most
obvious one, different specific conditions
are also worth their points.
Levers easily capture human imagination,
as you would have a clash of opponent
a6 blocked pawn above, supported by b5 pawns with the associated tension waiting
free pawn, will easily mutate to an to be resolved to influence the game, but
advanced 6th-rank passer, if b5-b6 break is assigning precise values is not that easy,
played unless you want to be too specific, as
frequently levers take up a range of
Frequency: very frequent different roles on the same squares, acting
as central breaks, wing breaks and
storming pawns breaks depending on the
Levers circumstances.
Here we will briefly discuss the general
Definition: a pawn attacking an enemy purpose of advanced levers on the 5th and
pawn is called a lever 6th ranks, and pay a bit of attention to
some other types of lever pawns.

Value: general-purpose bonus for

advanced levers on the 5th and 6th ranks
in terms of psqt

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 24 28 32 36 36 32 28 24
5 12 14 16 18 18 16 14 12
4 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

white advanced lever on the 5th rank on b5 advanced lever psqt(mg)

(the pawn tension between the b5 and c6
pawns will most likely open either the b, c,
or even a file)

56
 8 0 0 0 0 0 0 0 0 Outer central levers
7 0 0 0 0 0 0 0 0
6 16 18 22 24 24 22 18 16 An outer central lever is c4 pawn attacking
5 8 9 11 13 13 11 9 8 d5 pawn, or, alternatively, f4 pawn
4 0 0 0 0 0 0 0 0 attacking e5 pawn.
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

advanced lever psqt(eg)

Additional information: advanced levers

get their not very big, but well-deserved
bonus due to a combination of factors:
- they are very much conducive to opening
lines, be it in the center, one of the wings,
or in their capacity as storming pawns to
attack the enemy king
- in case the pawn exchange is avoided by
the opponent side by pushing the attacked
opponent pawn further up to release the
tension, or in case the lever side itself c4 outer central lever
avoids trading by doing a further pawn (a very welcome situation; both pawns are
push, if possible, the former lever situated on their 4th ranks, but the c4 pawn
immediately transforms into a mighty is less central. This means that after a
advanced non-lever pawn, or even passer possible exchange, white will remain with
- those pawns are extremely helpful at a more valuable central d pawn vs black's
breaking blocked positions/fortresses, less central c pawn. This is also one of the
involving the interlocking of many reasons why 1.c4 is such a good first
blocked own and enemy pawns, thus move: black simply can not play d7-d5)
avoiding potential draws for the weaker
side Value: 20cps bonus, exclusively mg

Levers certainly do change their quality

depending on whether they are supported Defended outer central lever
by another own pawn or not, whether they
are outer/inner levers(an outer lever would A defended outer central lever is an outer
be a lever located on a less central file than central lever, supported by another own
the opponent attacked pawn, an inner lever pawn on less central file than the file the
would be the exact opposite, and, of lever is placed upon.
course, in terms of centralisation, d/e files Specifically, that would encompass the
are more central than c/f files, which in following board arrangements: white
turn are more central than b/g files, with pawns on g3,f4, black pawn on e5; white
a/h files being least central), the rank they pawns on f3,e4, black pawn on d5; white
are placed upon, etc. pawns on c3,d4, black pawn on e5; white
pawns on b3,c4, black pawn on d5.
Below, we will look at a couple of more
salient evaluation features.

57
 defended outer black central lever on f5 b4 is an unopposed lever on the 4th rank
(Do you recognise the KID-like structure? (and yes, the b4-b5 push is a real threat)
It is not advantageous for white to capture
e4-f5, as in this case black's pawn structure Value: rather small, maybe some 7cps
significantly improves, trading a central e4 bonus, only for the mg
pawn, 4th-ranker at that, for a much less
central g6 one, 3rd-ranker at that, and
black threatens f5-f4 push with enormous Lever on the 3rd rank
increase of the pressure.)
A lever on the 3rd rank, attacking an
Value: 15cps bonus, only mg, presumably enemy defended pawn is worth some
over the bonus for an undefended outer bonus points too, mainly for the fact that
central lever, if that applies this threatens pawn exchange, in which
case either the defended enemy pawn,
advanced and valuable, will become
Unopposed lever on the 4th rank undefended, or disappear altogether.

Unopposed lever on the 4th rank is a lever

on the 4th rank that is not opposed by an
enemy pawn on the same rank.
Small bonus will be due in view of the
following reasons:
- as the pawn is not opposed, in case of a
pawn trade, the file upon which the lever is
will be opened, which usually will favour
the lever side
- in case the trade is avoided, in most cases
the unopposed lever will also have the
chance to move forward and become a
dangerous potential passed pawn, in case
there are pawns to support it, as the
squares to promotion are unoccupied by
enemy pawns

58
white lever on the 3rd rank on b3 attacking 8 0 0 0 0 0 0 0 0
a defended black lever on a4(this situation 7 70 85 95 110 110 95 85 70
definitely favours white, in spite of the fact 6 50 60 68 76 76 68 60 50
that the b3 pawn is more central than the 5 30 40 48 56 56 48 40 30
attacked enemy a4 pawn; a4-b3 capture 4 20 30 38 46 46 38 30 20
will trade advanced a4 black pawn for 3 13 18 24 32 32 24 18 13
modestly placed c2 white pawn, while b3- 2 6 8 12 14 14 12 8 6
a4 capture is also a threat, this time trading 1 0 0 0 0 0 0 0 0
3rd-rank b3 pawn for 4th-rank b5 pawn) a b c d e f g h
Value: modest bonus, 10cps, both for the passed pawn psqt(mg)
mg and eg
8 0 0 0 0 0 0 0 0
7 98 115 130 150 150 130 115 98
Passed pawns 6 72 90 98 105 105 98 90 72
5 42 60 72 84 84 72 60 42
Definition: a pawn that has no enemy 4 30 45 52 67 67 52 45 30
pawns on more advanced ranks than the 3 20 27 35 47 47 35 27 20
pawn itself up to the square of promotion 2 9 12 18 21 21 18 12 9
on the file it is placed upon, as well as the 1 0 0 0 0 0 0 0 0
2 adjacent files a b c d e f g h

passed pawn psqt(eg)

Additional information: passed pawns

are one of the most valuable pawns in
chess, of course, as promoting them would
increase significantly the material of the
promoting side.
There are different types of passed pawns,
protected ones, connected ones, very large
groups of connected passed pawns, other
very specific, but important cases, etc.
Here we will look briefly at the most
salient ones.

In general, passers would get their well-

well, c5 is an advanced passed pawn for deserved bonus for the following weighty
white, while a7 is a non-advanced passed reasons:
pawn for black - primarily, they are unopposed pawns,
whose promotion leads to material
Value: bonus, valid in terms of psqt increase
- advanced passers, especially if central
too, would also tend to restrict enemy
pieces' activity
- in different configurations, to be
investigated separately, their value is even
further boosted, sometimes to an enormous
extent

59
Frequency: very frequent

Protected passed pawns

Definition: a protected(defended) passed

pawn would be one supported by another
own pawn

c3 and d4 are connected passed pawns for

white, g5 and f5 are connected passed
pawns for black

Value: additional bonus is due, of course,

that would be seen by the psqtised bonus
for defended and aligned pawns.
Another ad-hoc bonus should be given
only in the case, when a connected passer
c6 is a protected passed pawn, very is neither defended, nor aligned.
dangerous, for the obvious reason that it is
strong and durable

Value: well, a bonus is due of course, over

the plain passed pawn bonus, within our
evaluation framework that would be seen
by the existing bonus for a defended pawn

Frequency: very frequent

Connected passed pawns

Definition: any passed pawn that has

another own passed pawn on adjacent file

c2 and d4 white pawns are neither

defended, nor aligned, but still connected
and valuable as tandem too.
f5 black pawn is also neither defended, nor
aligned, but still connected and valuable.

60
The size of the bonus should be
approximately 40cps, both for the mg and
the eg.

Additional information: connected

passed pawns get their bonus because:
- they are able to advance, support each
other and frequently control a range of
consecutive squares in tandem, which
makes their position on the board much
more stable, as well as their march towards
the squares of promotion much more
efficient
- in case a connected passer is supported, it
will be more durable, difficult to attack by
enemy pieces, while if it is an aligned
pawn, in tandem with the other own the white bishop on h2 blockades the well-
aligned pawn next to it they will control a advanced black h3 passer, while the black
range of consecutive squares on the rank in knight on b6 blockades the white b5 passer
front of them, also threatening a (as you see, the further advance of the
safe(defended) passer push with one of the passers is, at least temporarily, stopped)
passers reaching a more advanced rank by
force Value: small bonus, valid in terms of rank.
- even if such passers are neither defended, - 20cps, both mg and eg, when the
nor aligned, they still do threaten to blockading minor piece is on its 4th rank
become defended or aligned by relevant - 10cps, both mg and eg, when the minor
pawn pushes blockader is on its 3rd rank
- and 5cps, for both stages, when the
Frequency: frequent blockader takes the 2nd rank

Additional information: as said, this is a

Minor pieces blockading passers very useful feature, indeed. As a passer
promotion is a tremendous asset for the
Note: a blockade would be the placing of a promoting side, any effort at preventing
non-pawn piece on the rank immediately that would be very welcome. Stopping the
in front of the enemy passed pawn, so that further advance of the passer, as soon as
its further advance is, at least temporarily, possible, before it reaches more advanced
blocked. ranks, basically achieves 2 things:
No matter that one could doubt it, - the establishment of a stronger passer on
blockading of passers is an extremely a more advanced rank after a pawn push
useful and efficient feature, frequently - and making the enemy passer a more
underestimated by both top humans and vulnerable target for attacking pieces, as in
top engines alike. general any fixed/immobile object is easier
to reach and destroy
Definition: a minor piece, knight or
bishop, taking up the square in front of the Frequency: frequent
enemy passer
On occasions, the minor piece blockade
might be even more efficient, if the
blockading side restrains 2 or even more

61
enemy passers, as under such conditions well, although white might be a pawn up,
the cumulative effect of the blockade the excellently placed Nh6 fully closes the
would be bigger. game and a draw by fortress is extremely
likely, no matter the disposition of the
remaining white and black pieces(thus, for
blocked position purposes, not only the
number of pairs of blocked and
symmetrical twice backward pawns is
important, but also the existence of files
where a passer would be blockaded by an
enemy piece)

excellent black knights on a7 and b6 stop

the advance of the, otherwise mighty,
white a6 and b5 passers(as you can easily
see, even though a6 and b5 are connected,
and a6 defended, and both pawns being
advanced too, they somehow look pitiful
and the blockade very efficient)

Another important blockading feature of well, as you see, on occasions, other non-
minor pieces primarily, but different minor pieces are also quite efficient in
pieces too, is the attempt to fully close the achieving a fully blocked/fortress
game and thus achieve a draw. position(as Kh6 is above)

Centralised blockading minors

Definition: Knight or bishop on the

central c3,d3,e3,f3,c4,d4,e4 or f4 squares,
blockading an enemy passer

62
 humans and engines. Reason might be the
very positional nature of the term, as well
as the high depths associated with it.
Often, why this term is useful, will become
evident some 20-30 moves from now.
Bonus is given in view of the following
considerations:
- of course, the advance of the enemy
passer is stopped and, as it is a central one,
this function is even more important
- while blocking the center, the initiative
of the stronger side(usually the side with
the blockaded passer) on that section of the
board is also largely thwarted, and, as we
all know, the center is where most things
happen
Bc3 and Nd4 blockading enemy c4 and d5 - the blockading minor pieces themselves
passers in the center are placed on perfect centralised squares,
meaning that such pieces would efficiently
Value: sufficiently large bonus, valid in cumulate functions to great effect, apart
terms of psqt, only for the mg from blockading, attacking important
squares in the enemy half of the board/the
8 0 0 0 0 0 0 0 0 enemy king shelter, defending the own
7 0 0 0 0 0 0 0 0 king shelter, sometimes supporting the
6 0 0 0 0 0 0 0 0 advance of other own passers, etc.
5 0 0 0 0 0 0 0 0 - on very special occasions, with deep
4 0 0 40 50 50 40 0 0 positional considerations, such minors will
3 0 0 30 40 40 30 0 0 efficiently block the whole center together
2 0 0 0 0 0 0 0 0 with other own pawns, preventing
1 0 0 0 0 0 0 0 0 counterplay there and, while using their
a b c d e f g h added surplus value, giving the own side
excellent attacking chances
centralised blockading knight psqt

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 0 0 0 0 0 0 0 0
5 0 0 0 0 0 0 0 0
4 0 0 30 35 35 30 0 0
3 0 0 20 30 30 20 0 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

centralised blockading bishop psqt

Additional information: this is an

extremely useful feature in the mg, almost
always not taken into account by both

63
an excellent blockading knight on e4 - 10cps, both mg and eg, if the piece is a
largely prevents counterplay in the rook(the condition would also apply with
center(the e file is blocked, after all), an own rook placed behind the passer on
attacks the f6 square of the enemy king the same file, attacking the square in front
shelter, defends the f2 and g3 squares of of the passer on an x-ray)
the own king shelter and simultaneously - 5cps, both mg and eg, when the piece is a
supports the white passer on c5: queen
tremendous functionality, no one can deny
it! Obviously, the bonus will be due for the
ability to thwart the enemy passer's
advance or support the advance of the own
passer.

with fully blocked positions, the surplus

value of such centralised minor blockaders
will often incentivise kingside attacks(as
you can easily see on the diagrammed Ba5 supporting the advance of the own c6
position, the mighty Nd3 fully blocks the passer by controlling the c7 square in front
position, making impossible a d4-d3 push of the passer, Rc1 doing pretty much the
opening up the game and, although, same, but on an x-ray, and Nf1 thwarting
seemingly, black plays with a whole pawn the further advance of the enemy g4 passer
up, an impressive central passer at that, it by controlling the g3 square in front of it
is white that is winning, or at least having
a substantial advantage)
King supporting passed pawn
Frequency: infrequent
Definition: king, defending own passed
pawn
Pieces attacking the square in front of
an own or an enemy passer

Pieces attacking the square in front of an

own or an enemy passer get a small, but
well-deserved bonus, in the following
way:
- 15cps, both mg and eg, if the piece is a
minor

64
the white king on b5 supports the white c5 restricting white passer on c5
passed pawn
Value: bonus, applied in terms of ranks
Value: bonus, 10cps, just for the eg
- 12cps, both for the mg and eg, for the 5th
Additional information: the bonus is rank
given for the following reasons: - 18cps, both for the mg and eg, for the 6th
- the pawn is defended by the king, and rank
this is an important pawn - 30cps, both for the mg and eg, for the 7th
- the king can support the advance of the rank
passer towards the square of promotion, if
it controls the square in front of it Additional information: this is a very
- at the same time, the passed pawn can true term indeed, though skeptics might
shelter the king from enemy attacks say it is just a figment of someone's over-
exaggerated imagination. Bonus is due for
Frequency: very frequent 2 main reasons:
- the passer is well-protected and stable
there, going to last for a long time(of
Restricting passer course, well-protectedness will be valid for
any other protected passer, too, but the
Definition: passer, on ranks 5, 6 or 7, distinction here is with durability, as the
protected by an own pawn, blocked by an condition of the protecting pawn being
enemy pawn blocked by an enemy pawn significantly
adds to it, as the blocking enemy pawn
kind of perpetuates the construction,
making enemy attacks upon the defending
pawn much more difficult, as the enemy
blocking pawn will shelter it from direct
attacks of heavy pieces along the closed
file, where both pawns are, but also
significantly restrict the access of other
enemy pieces to it)
- precisely because of the same blocked
construction, enemy pieces will have very

65
hard time dealing with the passed pawn,
trying to get access to it and blockade it,
while, own pieces will be reversely helped
by the above-mentioned condition, as well
as the supporting function of the passer
concerning penetration into the enemy
camp, especially with more advanced
passers

Of course, above conditions also suppose,

that the side with the passer will naturally
have more time to organise efficient
attacking regrouping, while the opposite
side will mainly shuffle around.

Such passers are especially dangerous

when on more advanced ranks, as the and, on the 7th rank, they are simply
restricting effect is severely amplified. thrashing

Frequency: frequent

Spearhead connected passer

Definition: a spearhead pawn, with the

pawn defending it blocked by an enemy
pawn, and the pawn defending that pawn,
all 2 part of the longer chain, also blocked
by an enemy pawn, and another own
passed pawn present on the other adjacent
file

on the 6th rank, such passers often have

cramping effect

b5 is a spearhead passer. It is a spearhead

pawn, the head of the d3-c4-b5 long pawn

66
chain, the pawn defending it, c4, is enemy pieces to blockading, trying to stop
blocked by an enemy pawn, c5, and the the further advance of the 2 connected
pawn defending c4, d3, is also blocked by passers, is made much more difficult,
an enemy pawn, d4, with both being part because of lack of sufficient space
of the longer chain, and the b5 pawn has - the very same blocked condition, and that
another own passer on adjacent file, a4. on a larger scale, will, on the other hand,
significantly benefit the regrouping and
coordination of own pieces, supporting the
advance of the passed pawns, as well as
their general activity
- at least the first blocking enemy pawn
next to the spearhead passer on the same
rank and adjacent file, e6 on the second
diagram, will remain undefended and a
much easier target for attack, because it
will be squeezed between 2 opponent
defended pawns

Couple of examples with similar arising

structures:

another spearhead passer, f6, this time on

the 6th rank. Maybe you can check the
relevant conditions yourselves.

Value: large bonus, 70cps in the mg,

35cps in the eg

Note: only spearhead connected passers on

the 5th through 7th ranks will be counted,
as otherwise less advanced pawns are not
so dangerous

Additional information: this is an

extremely interesting feature, of which
both top humans and top engines seem to well, on the second-posted diagram,
be completely unaware of. The primary accompanying the definition, any minor
reason for that might be the lack of piece sacrifice on g6 will bring us to the
sufficient knowledge, the unresearched appearance of the term; if engines or
phenomenon, as well as the astounding humans are unaware of its relevance, they
depths involved in the variations. might very well also not take their chance
and sacrifice
The very-well deserved bonus is due for
the following reasons:
- the longer pawn chain, of which the
spearhead is the leading pawn, with most
of its members blocked by enemy pawns,
creates a situation, where the access of

67
 sacrifice on b4, after which, no matter
what minor piece is sacrificed first, it
should get a big, winning advantage.
For the minor piece, black gets 2 strong,
connected passers, c4 and b5, both
currently defended, one of them advanced
on the 5th rank, both free in their
movements, and both supported in their
movement forward by the pair of rooks on
the c and b files, as well as other pieces,
plus, after breaking white's chain pawn
structure, both the d4 white pawn, and
especially the a5 pawn, becoming isolated,
transforming into vulnerable targets.
Certainly, the compensation is more than
sufficient. Besides, the larger supporting
taking the first-posted diagram, black long chain pawn structure, in the
accompanying the definition, any minor form of the d5 and e6 pawns, both blocked
piece sacrifice on a5 will bring us to the by enemy pawns, kind of suffocate the
condition, or, alternatively, a knight bigger number of white pieces, making
sacrifice on c5, followed by a bishop their coordination much more difficult.
capture on a5 The friendly pieces, on the other hand,
enjoy significantly greater freedom of
So, usually, the feature will be reached movement and better coordination,
after a sacrifice, but other paths are because of the same fact, and that
possible as well. condition will only improve as the game
progresses, as the passers start moving
forward, squeezing even more white's
position, and the black pieces manage to
regroup better.
Overall, white has almost no chances to
save the game.
How many very top engines would see a
minor piece sacrifice on b4 and evaluate it
as winning? How many humans will think
a sac on b4 wins by force?

well, if either side does not find a way to

open the position, the game will probably
end in a draw, because of the blocked
character of the position. Many might
indeed think the game is more or less
drawn, be it humans or engines, but, in
actual fact, black has a very-well thought

68
 As a whole, one evaluation term for people
and entities that like deep, entertaining and
beautiful play.

Frequency: infrequent

Rollercoasters

Definition: a large group of connected

passers or passers and candidate passers on
adjacent files, 4, 5 or 6 of them

here the position after the possible knight

sacrifice. Black has quite some advantage
and will win, but that might take a lot of
time, frequently beyond the search horizon
of an engine.

c3-d4-e4-f5 is a rollercoaster of 4
connected passers

the bishop sacrifice is winning, too, but

associated lines are also very deep,
certainly beyond the horizon of many
engines and humans

The mg bonus is significantly higher, as in

the mg the restricting effect of the long
pawn chain and the blocked structure upon
the larger number of enemy pieces will be
much more severe.
a rollercoaster of 5 connected passers,
a2,b2,c2,d3 and e3

69
 Additional information: fact is, that with
such extremely large connected pawn
formations the existing bonuses for passed
pawns, candidate passers and connected
pawns, defended or aligned ones, are
definitely insufficient.
The large formations, over 4 pawns,
represent additional assets, for which the
over-bonus is given:
- a compact mass of pawns, able to defend
and advance in supporting each other
- massive control of the squares in front of
the pawns, with no existing gaps, so
enemy pieces will have very hard time
coming closer, trying to attack them
- for the very same reason, the task of
now, the rollercoaster pawns are already 6, enemy pieces trying to blockade them is
with 5 passers, plus the f2 candidate passer extremely arduous, if not impossible at all
- because of the inability of enemy pieces
to come closer, in moving forward, such
formations are able to very efficiently gain
space

The bonus is the same, no matter if the

pawns are only passers, or a mix of passers
and candidate passers, for the simple
reason that, with such large formations,
with pawns supporting each other and
restricting enemy pieces, candidate passers
are able to quickly transform into fully-
fledged passers in a short while almost
automatically. So, in this sense, it is
difficult to make a distinction between
passers and candidate passers.

another mix of passers and candidate The mg and eg bonuses are equal, as,
passers in a 4-pawn rollercoaster. d5 and while in the mg such pawns will have a
e5 are passers, while c4 and f4 are major restricting role upon the larger
candidate passers. number of enemy pieces present, in the eg
their advance will be generally easier.
Value: sufficiently large over-bonus,
dispensed in terms of the quantity of the
pawns

4 connected pawns: 40cps, both for the mg

and eg
5 connected pawns: 60cps, both for the mg
and eg
6 connected pawns: 80cps, both for the mg
and eg

70
although white has 2 pieces more, with the an engine, or even a human, might decide,
material equivalent being 2 minor pieces that white is ok, because it has many more
for just 4 enemy pawns, it is definitely pawns. However, the most advanced
black who has the advantage. passer of those pawns, the one on e3, is
I am not certain how much time top significantly less advanced than the black
engines will need to fully realise that, but b3 passer, so in actual fact black is much
the fact is indisputable. better.
Quite frequently, as seen above, such
constellations lead to beautiful positions
with accompanying astounding, tactically
relevant and quickly changing play.

Frequency: infrequent

Unstoppable passed pawn

Definition: with the existence of at least

one own and one enemy passer, the most
advanced passer on the board, provided
that it is at least 2 ranks more advanced
than the most advanced passer for the
opponent side

Value: bonus, 20cps in the mg, 30cps in with queen endings, this condition might
the eg frequently lead to draws, in spite of one
side having significant material advantage.
Additional information: the bonus is due, Although black has 3 more passed pawns
because such passed pawns are much than white above, the game will end in a
stronger than the rest, closer to promotion, draw, as the single white passer is way
and play a vital role in deciding the game. ahead of the huge black pack.

Frequency: frequent

71
 More pieces with passed pawns will have to retreat, so the march of the
passer is more or less forced.
Definition: at least one side having at least
a single passed pawn, with unequal
number of pieces for both sides

Value: sufficient bonus, 20cps in the mg,

40cps in the eg, for the side with more
pieces

Additional information: the bonus is

very-well due, because more pieces are
useful in dealing with passers in 2 ways:
- by efficiently supporting the advance of
friendly ones, and
- by efficiently stopping the advance of
enemy ones

it is not possible for black to win that one.

In spite of the huge material deficit, white
is holding the draw by just shuffling the
rook to f3/h3 and back to b3. The b4
passed pawn can not advance any further,
as it is very efficiently stopped by the
larger number of white pieces of lower
power, with the bishop on d5 and the rook
both controlling the square in front of it.

Frequency: frequent

Passer-makers
in spite of the evident material deficit, only
black could have advantage above, as the Definition: unopposed pawn on the 4th or
strong centrally placed black passers are 5th ranks, defending an own pawn on one
excellently supported by the friendly adjacent file, that is blocked by an enemy
pieces. pawn, which pawn in turn is not a
The black predominance in numbers of defended one, and with no enemy pawns
pieces of lower power allows the lower- on the other adjacent file in front of it
power pieces to efficiently protect the own
passers, when under attack by enemy Value: bonus, dispensed in terms of rank
higher-power pieces and, even more
decisively, be extremely beneficial to their - 4th rank: 7cps, both for the mg and eg
advance, by controlling squares on the - 5th rank: 15cps, both for the mg and eg
path to their promotion. When a heavy
piece on the path of the passed pawn to Additional information: the bonus is
promotion is attacked by a minor piece, it given, as such pawns, after a push, might
help in creating an advanced passed pawn
in the like of the friendly defended pawn.

72
 passer, as the black f7 pawn will be
stopping its further advance.

b4 is an unopposed passer-maker on the

4th rank.
After the b4-b5 push, in the case of a6-b5
capture, the passer-maker is sacrificed, but the condition with an unopposed passer-
a much stronger advanced passed pawn on maker on the 5th rank, as f5 is above, is
a5 arises instead, ready to continue its even more beneficial.
march to promotion with a5-a6 at any After f5-f6 g7-f6 g6-g7, the white g pawn
time. has almost promoted.

Frequency: frequent

Potential passers

Definition: a pawn that is not opposed,

provided that the number of other own
pawns on the same rank or less advanced
ranks on adjacent files is not smaller than
the number of enemy pawns on more
advanced ranks on adjacent files

Note: of course, such a pawn should not

be a passer, as passers already get their
bonus
the condition the enemy pawn, blocking
the friendly defended pawn on adjacent
file, is not in turn defended by a pawn, is
necessary, as otherwise, similar breaks in
the center, might not lead to the creation of
a passed pawn.
Above, after the d4-d5 break, and e6-d5
capture, the white e5 pawn is still not a

73
a3 is a potential passer for white(b3 vs b6 and on the diagrammed position, although
pawns on adjacent files), and g5 is a white g3 pawn does not formally satisfy
potential passer for black(again with equal the rule(a single white pawn on same or
pawn numbers on adjacent files, f3 and h3 less advanced ranks supporting it, h3, vs 2
vs f5 and h6 pawns) enemy pawns on more advanced ranks
opposing it, f5 and h6), if white were to
Of course, there are always exceptions to play, g3-g4 push would render g4 pawn
the rule, as chess is simply too multi- very much potential passer/passer-like,
faceted, but the general conception should with g4-g5 threatening
hold.
Value: bonus, valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 25 30 34 38 38 34 30 25
5 15 20 24 28 28 24 20 15
4 10 15 19 23 23 19 15 10
3 6 9 12 16 16 12 9 6
2 3 4 6 7 7 6 4 3
1 0 0 0 0 0 0 0 0
a b c d e f g h

potential passer psqt(mg)

for example, although formally satisfying

the conditions, c4 white pawn will have a
very difficult time becoming a passer, as
one of the pawns that could support its
march forward, d3, is actually blocked by
an enemy pawn and thus immobile

74
 8 0 0 0 0 0 0 0 0 passers after f6-f5, e5-e4 and d5-d4 is
7 36 45 49 52 52 49 45 36 quite realistic
6 25 30 34 38 38 34 30 25
5 21 30 36 42 42 36 30 21 Value: sufficiently large additional bonus,
4 15 22 26 33 33 26 22 15 30cps both for the mg and eg(well, when
3 10 13 18 24 24 18 13 10 you give the bonus for one of the pawns,
2 5 6 9 10 10 9 6 5 you actually assign it to the tandem)
1 0 0 0 0 0 0 0 0
a b c d e f g h Additional information: the bonus is
dispensed for the fact that, quite often, this
potential passer psqt(eg) particular constellation will lead to the
creation of 2 strong connected passers
Additional information: potential passers
are bonised, of course, for the single
reason that, at some future point in time, Mainstays
they could become passers
Definition: a pawn on the central c4,d4,e4
Frequency: frequent or f4 squares, blocked by an enemy pawn,
controlling the square in front of an enemy
backward pawn and simultaneously
Pair of potential passers defending an own passer

Definition: 2 potential passers for one side

situated on adjacent files, with both of
them having another own pawn on the
other adjacent file looking away from the
file the neighbouring potential passer is

d4 is a mainstay pawn
(d4 is blocked by d5, supports own c5
passer and controls the e5 square in front
of the enemy e6 backward pawn)

Additional information: an extremely

well, d5 and e5 are just 2 potential passers valuable pawn, especially in the mg. A
on the diagrammed position, but in actual nice bonus is due in consideration of the
fact they hide much more in their following:
interconnection as a cumulative influence; - such a constellation very favourably
certainly, the possibility for the immediate splits the opponent position in 2, while
building of a tandem of 2 connected retaining all associated advantages, like

75
the passed pawn, enemy backward pawn;
this split ensures much greater own pieces
activity, while restricting opponent pieces
activity, which might play a vital role,
especially in the long run
- with bigger blocked pawn structures and
closed-like game, the role of the mainstay
further increases, as the central enemy
backward pawn on the 3rd rank will be a
major weakness with even bigger
cramping effect upon the own pieces, and
this could lead to a gradual, but very
convincing king-side attack upon the
enemy king
- the square in front of the enemy
backward pawn is an ideal place for a
minor outpost; a knight or bishop outpost this time, the larger group of pawns
will simultaneously attack the enemy king includes one defended aligned pawn, d4,
position and support the advance to and one twice aligned pawn, e4
promotion of the strong defended passer

Compact pawn structures

Definition: compact pawn structures are

larger groups of at least 2 twice aligned,
twice defended, defended aligned,
defending aligned or long chain pawns

the larger group of pawns includes one

twice defended pawn, b5, and one long
chain pawn, c4

the b3,c4,d4 and e3 pawns are a larger

group of 2 defended aligned pawns, c4 and
d4

76
one twice defended pawn, f4, and one very large compact pawn structure,
defending aligned pawn, g3 consisting of 3 defended aligned pawns,
b3, d4 and g4, 2 twice aligned pawns, e4
and f4, and one defending aligned pawn,
c3

Value: such structures get their very nice

bonus through the already existing bonus
points for twice defended pawns, twice
aligned pawns, defended aligned pawns,
defending aligned pawns and long chain
pawns. The larger the structure, the bigger
the cumulative bonus.

Additional information: the bonus is

given for the following reasons:
- the pawns co-exist as a compact mass,
supporting each other, and thus being less
vulnerable to enemy attacks
larger compact group of pawns, including - the pawns are able to move forward in
one long chain pawn, c3, one defended harmony and mutual support, posing
aligned pawn, d4, and one defending bigger problems to the opponent in terms
aligned pawn, e4 of stopping their advance
- the larger group very efficiently restricts
enemy pieces' mobility, the larger the
group, the more pronounced the effect, as
the pawns almost leave no holes,
undefended squares, which enemy pieces
could use to penetrate

Such larger structures are very efficient

both in attack and defence.

77
 The structure as a whole also very much
simulates closedness of the position,
although there are just a few blocked
pawns. The larger pawn structures are
simply very much conducive to later fuller
closure or at least will ward off for quite
some time possible enemy tries at opening
the game.
For this very same reason, the simulated
closedness, the white king, although
playing completely without pawn shelter,
is feeling extremely well and healthy, with
enemy threats just a distant reminder. So,
larger compact groups of pawns are also
extremely beneficial to king safety. This is
a subtle king safety term, allowing for
white has a compact very large pawn successful play with almost completely
structure, including 5 connecting pawns: insecure king.
b3, long chain pawn, c4, twice defended
pawn, e4, long chain pawn, f5 and g5,
defended aligned pawns.
Much in contrast, although many humans
and engines might not be quite able to
realise it, black has only 2 connecting
pawns: d4, which is twice defended, and
g7, which is twice aligned.
In this way, white enjoys big advantage in
terms of much more compact pawn
structure. This is certainly decisive, and
white has excellent winning chances.
Please note, how efficient the connecting
white pawns on the king side are. f5 and
g5 pawns are defended and strong, the g5
pawn supports a possible f5-f6 push, the f5
pawn, a possible g5-g6 push, those pawns
plus the e4 long chain one considerably compact pawn structures are very useful in
limit the mobility of a large pool of black defence too.
pieces. Although black has substantial lead in
The compact mass of white pawns on the development, and very robust pawn center,
queen side, on the other hand, is very the game is about equal. The reason is that
handy in preventing possible quick black it is very difficult to break through the
counterplay there, as the b3 and c4 white defensive bastion of connecting
defended pawns are ready for any enemy pawns. Black has just a single connecting
pawn assault, just waiting and gaining pawn, d5, which is twice aligned, while
time, as any enemy pawn attack, for white enjoys the presence of 6! such
example after b7-b5, or a6-a5-a4, is quite pawns: b2, which is twice aligned, c2,
unsubstantial, as captures like b5-c4 or a4- which is defending aligned, d3, which is
b3 will only reproduce the attacked defended aligned, e3, similarly so, f2 and
defended pawn after a recapture. g2 defending aligned.

78
This compact mass of pawns wards off any Twice aligned pawns
possible enemy piece penetration, so black
will have to work very hard to find a Definition: a pawn that has 2 other own
potential exploitable weakness. pawns next to it on the same rank on
adjacent files

one last example for utter enjoyment.

In spite of the enormous lead in twice aligned pawn on d3
development and massive center, white is
actually a bit worse. How many Value: bonus valid in terms of psqt
engines/humans would assess the position
in this way? 8 0 0 0 0 0 0 0 0
Fact is, that white's pawns are quite 7 0 30 35 40 40 35 30 0
broken-down in different very small 6 0 19 22 25 25 22 19 0
groups, while black has a great number of 5 0 10 15 20 20 15 10 0
interconnecting pawns. Look at the h6-g6- 4 0 6 8 10 10 8 6 0
f7-e7-d6-c6-b5-a5 weaving snake! It is so 3 0 3 4 5 5 4 3 0
inseparable and so powerful. I guess this 0 1 2 3 3 2 1 0
2
time you will be able to make out
1 0 0 0 0 0 0 0 0
yourselves what the 6 connecting black
a b c d e f g h
pawns are. This structure threatens attack
on the queen side, counterplay in the
twice aligned pawn psqt(mg)
center, significantly limits the mobility of
the white pieces, and would not allow easy
8 0 0 0 0 0 0 0 0
access to its king.
While white will have to spend quite some 7 0 20 22 25 25 22 20 0
time searching for an exploitable 6 0 12 14 16 16 14 12 0
weakness, black will be able to develop, 5 0 7 10 13 13 10 7 0
and the white lead in development will 4 0 4 5 7 7 5 4 0
disappear in and of itself. In this way, a 3 0 2 3 4 4 3 2 0
single pawn feature turns the whole game 2 0 1 2 3 3 2 1 0
around. 1 0 0 0 0 0 0 0 0
a b c d e f g h
Frequency: very frequent
twice aligned pawn psqt(eg)

79
Additional information: twice aligned 8 0 0 0 0 0 0 0 0
pawns are an extremely powerful asset. 7 0 30 40 50 50 40 30 0
They should get a beautiful bonus in view 6 0 20 25 30 30 25 20 0
of a variety of reasons: 5 0 10 15 20 20 15 10 0
- very nice compact structure; no matter 4 0 5 7 9 9 7 5 0
what pawn of the three moves ahead, the 3 0 2 3 4 4 3 2 0
structure as a whole still remains very 2 0 0 0 0 0 0 0 0
flexible and very valuable. Upon moving 1 0 0 0 0 0 0 0 0
one square upwards, the twice aligned a b c d e f g h
pawn becomes twice defended one,
another asset, while if one of its twice defended pawn psqt(mg)
neighbours goes forward one square, the
twice aligned pawn is transformed into a 8 0 0 0 0 0 0 0 0
defending aligned pawn, also an asset
7 0 20 25 33 33 25 20 0
- massive control of consecutive squares
6 0 13 17 20 20 17 13 0
on the rank in front
5 0 7 10 13 13 10 7 0
- beautiful king shelter feature, if available
4 0 3 5 6 6 5 3 0
- if both the twice aligned pawn, as well as
its neighbours are passers, they represent a 3 0 2 3 4 4 3 2 0
tremendous force on their march to the 2 0 0 0 0 0 0 0 0
square of promotion 1 0 0 0 0 0 0 0 0
a b c d e f g h
Frequency: frequent
twice defended pawn psqt(eg)

Additional information: twice defended

Twice defended pawn pawns get their well-deserved bonus due
to a couple of weighty factors:
Definition: a pawn defended by 2 own - they are extremely strong, meaning also
pawns durable
- they are flexible, in case one of the
pawns defending the twice defended pawn
moves ahead, the whole structure will still
be valuable, with the twice defended pawn
becoming defended aligned and still
connected to 2 other own pawns
- of course, such pawns, if the defending
pawns are also passers, represent a very
powerful advancing unit

Frequency: frequent

Defended aligned pawn

Definition: a pawn that is defended by an

twice defended pawn on e5 own pawn placed on one of the adjacent
files and has another own pawn next to it
Value: bonus valid in terms of psqt on the same rank on another adjacent file

80
 valuable structure. Should be bonised due
to a mix of assets it creates:
- the pawn itself is strong, durable, and
difficult to attack by opponent pieces
- binds together a beautiful compact
structure, which is at the same time very
flexible
- in case the pawn next to the defended
aligned pawn moves forward, the defended
aligned pawn is transformed into a long
chain pawn, another valuable asset, while
if the pawn defending it advances, the
defended aligned pawn assumes the form
of a twice aligned pawn, a cherished asset
in all stages of the game(on the
diagrammed position, if f5 pawn advances,
defended aligned pawn on g5 we have the h4-g5-f6 white long pawn
(this one is additionally a storming pawn) chain, with the g5 pawn at its center, while
when h4 pawn advances, we have g5 at the
Value: bonus valid in terms of psqt center of the f5-g5-h5 aligned pawn
structure)
- g5 itself moving ahead gets us to a more
8 0 0 0 0 0 0 0 0 advanced defended pawn on g6
7 0 25 30 35 35 30 25 0
6 0 15 18 21 21 18 15 0 Frequency: frequent
5 0 8 10 12 12 10 8 0
4 0 4 5 6 6 5 4 0
3 0 2 3 4 4 3 2 0 Defending aligned pawn
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 Definition: a pawn that has one own pawn
a b c d e f g h on the same rank next to it on one adjacent
file and another own pawn that it defends
defended aligned pawn psqt(mg) on another adjacent file

8 0 0 0 0 0 0 0 0
7 0 17 20 22 22 20 17 0
6 0 10 12 14 14 12 10 0
5 0 5 7 9 9 7 5 0
4 0 3 4 5 5 4 3 0
3 0 2 3 4 4 3 2 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

defended aligned pawn psqt(eg)

Additional information: salient pawn

feature, part of a very nice compact and

81
 b3 is a defending aligned pawn

Value: bonus valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 0 15 18 21 21 18 15 0
5 0 8 11 14 14 11 8 0
4 0 4 5 6 6 5 4 0
3 0 2 3 4 4 3 2 0
2 0 1 2 3 3 2 1 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

defending aligned pawn psqt

(same values mg and eg)
c4 is a long chain pawn
Additional information: bonised due to (see how beautiful, even outwardly, the
following considerations: structure is)
- binds together a compact structure, which
simultaneously controls a number of Value: bonus valid in terms of psqt
consecutive squares
- apart from being compact, the structure is
flexible; if the pawn next to the defending 8 0 0 0 0 0 0 0 0
aligned pawn moves forward, it will be 7 0 0 0 0 0 0 0 0
defended, while in case the defending 6 0 24 35 48 48 35 24 0
aligned pawn itself goes forward, it 5 0 12 18 24 24 18 12 0
transforms into a defended aligned 4 0 6 12 17 17 12 6 0
pawn(see c3 and b3 pawns advancing 3 0 2 3 5 5 3 2 0
above) 2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
Frequency: frequent a b c d e f g h

long chain pawn psqt(mg)

Long chain pawn 8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
Definition: pawn that is defended and
6 0 16 25 33 33 25 16 0
defends another own pawn along the same
5 0 8 12 16 16 12 8 0
diagonal
4 0 5 8 13 13 8 5 0
3 0 2 3 4 4 3 2 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

long chain pawn psqt(eg)

Additional information: Long chain

pawns are extremely useful assets, whose

82
real value is way underestimated by both this time, apart from being long chain
top human players and top chess engines pawn, c4 is also a very long chain pawn,
alike. and the bonus for a long chain pawn
The lines such structures lead to are simply should be added to the bonus for a very
too deep and multi-branched. long chain pawn(the chain structure is
Nice bonus over the bonus for a simple much larger now, you see, much stronger,
defended pawn is due because: occupies much bigger space, restricting
- the pawn itself is strong, and the pawn it enemy pieces and giving freedom to own
defends is strong too ones, so it has a per se value, which the
- being long and connected means the accumulation of simpler bonus points
structure as a whole is compact, it is alone is not able to fully capture)
difficult for enemy pieces to break through
such a bastion, and apart from that it Value: bonus valid in terms of psqt
supports a wide range of friendly pieces
activities, which are sheltered in their 8 0 0 0 0 0 0 0 0
movements and attacks upon the enemy 7 0 0 0 0 0 0 0 0
side 6 0 0 0 0 0 0 0 0
- the structure is also reasonably flexible, 5 0 24 36 48 48 36 24 0
in spite of the fact it might look otherwise; 4 0 12 24 34 34 24 12 0
if the pawn defending the long chain pawn 3 0 4 6 10 10 6 4 0
advances, the long chain pawn itself is 2 0 0 0 0 0 0 0 0
transformed into a defending aligned 1 0 0 0 0 0 0 0 0
pawn, while if the long chain pawn itself a b c d e f g h
budges, it becomes a more advanced
aligned pawn very long chain pawn psqt(mg)
Frequency: frequent 8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 0 0 0 0 0 0 0 0
Very long chain pawn
5 0 16 24 32 32 24 16 0
4 0 9 16 22 22 16 9 0
Definition: a long chain pawn defending
another own long chain pawn 3 0 3 4 8 8 4 3 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

very long chain pawn psqt(eg)

Additional information: very long chain

pawns are valuable because:
- they are part of and represent an
intrinsically solid structure
- the sheer size of the structure will largely
restrict opponent pieces while supporting
friendly ones at the same time
- the larger size of the whole structure
determines to a great extent also its
durability, and durability in chess is
usually an asset

83
- yes, the structure is partially flexible too, spearheads can also represent fully
in spite of its large size(see long chain blocked chains
pawns); of course, if one of the constituent
pawns moves, the structure as a whole will
crumble

Frequency: infrequent

Spearheads

Spearheads are the most advanced pawns

of a long chain, consisting of at least 3
pawns.

or partially blocked ones. This time, d4

black pawn is the spearhead of the b6-c5-
d4 long chain.

b5 is the spearhead pawn of the d3-c4-b5

long chain

or long chains, consisting of more than 3,

or many more than 3 pawns. Above, c6 is
the spearhead of the very long chain g2-f3-
e4-d5-c6.

Spearheads are especially important in

terms of conceptual definitions.

Value: within our evaluation framework,

there is no need for any special bonus for
spearheads, as they are already very well

84
seen by the already existing bonus points
for advanced defended pawns, plus the
bonus for long chain pawns, the
connecting element, defining any longer
chain

Weak pawns

Undefended pawns

Within our evaluation framework, pure

undefended pawns are not considered, as it
is much more correct to take into account
different types of undefended pawns d4 is an isolated pawn
instead, as isolated ones, vertically isolated h5 is another isolated pawn, for black
ones, backward ones, etc. (no white pawns on either c or e files, and
Undefended pawns that are part of a chain, no black pawns on adjacent g file)
their root or base, should not get penalty,
as, in case they are backward, their penalty Note: it very much makes sense to score
is already ensured, while, if this is not the isolated pawns in terms of
case, the chain as a whole is a strong asset, opposed/unopposed flags, as unopposed
so it is completely meaningless to give isolated pawns are more easily attackable
bonus to one of its parts, while penalising by virtue of the fact that the file the
another. unopposed isolated pawn is placed upon is
Undefended pawns that are aligned are a semi-open file, where enemy heavy
also too strong to assign them a negative. pieces could be placed to endanger the
pawn(for example, d4 white pawn above is
unopposed isolated one, attackable by an
Isolated pawns enemy rook or queen along the d file,
while h5 black pawn is opposed isolated
Definition: a pawn that has no other own one, not attackable by white heavies along
pawns on adjacent files the closed h file)

Value: large penalty, valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 -20 -25 -30 -35 -35 -30 -25 -20
6 -18 -23 -28 -33 -33 -28 -23 -18
5 -16 -21 -26 -31 -31 -26 -21 -16
4 -14 -19 -24 -29 -29 -24 -19 -14
3 -12 -17 -22 -27 -27 -22 -17 -12
2 -10 -15 -20 -25 -25 -20 -15 -10
1 0 0 0 0 0 0 0 0
a b c d e f g h

isolated opposed pawn penalty(mg)

85
8 0 0 0 0 0 0 0 0 while suitable tactics is far from always
7 -25 -32 -40 -45 -45 -40 -32 -25 available; in this way, in order to render
6 -23 -30 -38 -43 -43 -38 -30 -23 the isolated pawn non-isolated, one needs
5 -21 -28 -36 -41 -41 -36 -28 -21 major other positional advantages in terms
4 -19 -26 -34 -39 -39 -34 -26 -19 of specific factors
3 -17 -24 -32 -37 -37 -32 -24 -17 - in a range of cases, when the isolated
2 -15 -22 -30 -35 -35 -30 -22 -15 pawn is blocked by an enemy pawn, or
1 0 0 0 0 0 0 0 0 when the enemy has sufficient pawn and
a b c d e f g h
piece control of the square in front of it, in
case it is not blocked, this pawn becomes
isolated opposed pawn penalty(eg) an even bigger weakness, as both fixation
by blocking and square control lead to
8 0 0 0 0 0 0 0 0
impossibility of the pawn to move
7 -27 -33 -38 -45 -45 -38 -33 -27
forward, which basically means greater
6 -24 -30 -35 -42 -42 -35 -30 -24
difficulties of getting rid of it by a pawn
5 -21 -27 -32 -39 -39 -32 -27 -21
-18 -24 -29 -36 -36 -29 -24 -18
push, challenging an enemy pawn, as well
4
3 -15 -21 -26 -33 -33 -26 -21 -15
as much easier targeting by opponent
2 -12 -18 -23 -30 -30 -23 -18 -12 pieces
1 0 0 0 0 0 0 0 0
a b c d e f g h

isolated unopposed pawn psqt(mg)

8 0 0 0 0 0 0 0 0
7 -33 -40 -50 -57 -57 -50 -40 -33
6 -30 -37 -47 -54 -54 -47 -37 -30
5 -27 -34 -44 -51 -51 -44 -34 -27
4 -24 -31 -41 -48 -48 -41 -31 -24
3 -21 -28 -35 -45 -45 -35 -28 -21
2 -18 -25 -35 -42 -42 -35 -25 -18
1 0 0 0 0 0 0 0 0
a b c d e f g h

isolated unopposed pawn psqt(eg)

Additional information: Isolated pawns f5 is a black isolated pawn, blocked by an

are a very widespread and important enemy pawn, which makes its advance f5-
positional feature. Along with doubled f4 to try getting rid of the weakness
pawns, they are probably the easiest to impossible currently, as well as very
recognise intuitively on the board. difficult to arrange through different
Penalty is due in view of the following tactics; of course, such a pawn is
weighty reasons: additionally handicapped and should get
- they are weak(undefended), so easily over-penalty for this specific condition
attackable and capturable
- as there are no other own pawns on
adjacent files, it is practically impossible
to easily span the distance to other own
pawns across files to build a valuable
compact structure in the short term without
resorting to major tactical arrangements,

86
 Value: small penalty, -2cps in the mg, -
3cps in the eg

Additional information: well, such a

pawn definitely constitutes an additional
weakness, as the enemy pawn blocking it
will restrict its movements, making it an
easier, immobile target. Besides, it will be
restricted on a less advanced rank, which
will further highlight its fragility. The
enemy pawn, on the other hand, blocking
it, will not be vulnerable as much, as by
definition it will be a non-isolated pawn,
so other enemy pawns will support or
potentially be able to support it.

well, sufficient control over the d4 square Frequency: frequent

by the white pieces makes d5-d4 pawn
push extremely difficult or impossible to
achieve either in the short or longer term; Knight and pawn immobilising enemy
in this way, the weakness is amplified isolated pawn

Frequency: very frequent Definition: knight and defended pawn

simultaneously attacking the square in
front of enemy isolated pawn
Fixed isolated pawn

Definition: isolated pawn, on ranks 2, 3 or

4, that is blocked by an enemy pawn that is
not isolated

the knight on c2 and the defended pawn on

c3 represent that condition

Value: small bonus, 5cps in the mg, 3cps

in the eg
b3 is a fixed isolated pawn on its 3rd rank.
g4 is another such pawn on its 4th rank. Additional information: the bonus is due
for the fact, that in this way the enemy

87
isolated pawn is highly probable to be demise. Own pieces supporting the
immobile. advance will help in no way either.

On the diagrammed position, for example, Frequency: frequent

the black b5 pawn can not successfully
advance one square, as it will be lost with
no compensation. In case only the c3 pawn Pawn controlling the square in front of
had been controlling the b4 square in front enemy doubled isolated pawn
of it, the advance would still be possible,
and that could open lines for attack.
The condition requiring the friendly pawn
to be defended is necessary, as otherwise it
too would be vulnerable, and the whole
formula would not make much sense.

Frequency: frequent

2 pawns controlling the square in front

of an enemy isolated pawn

the c3 pawn controls the square in front of

the black b5 doubled isolated pawn

Value: bonus, 8cps, both for the mg and

eg

Additional information: the bonus is due

for the ability of the pawn to stop 2 enemy
pawns in their advance at the same time.
As easily seen on the diagrammed
position, as both the b5 and b7 black
pawns are isolated, with no friendly pawns
the white b3 and d3 pawns control the on adjacent files capable of supporting
square in front of the black isolated pawn their advance, the c3 pawn stops their
on c5 forward movement single-handedly. The
b5 pawn can not advance and, because of
Value: small bonus, 5cps, both for the mg it, the b7 pawn going behind it, can not
and eg advance too.

Additional information: the bonus is due Frequency: frequent

for the obvious reason, that the enemy
isolated pawn is completely logically
immobilised, as any its advance,
unsupported by a friendly pawn that is
unavailable on adjacent file, will lead to its

88
 Pair of central isolated pawns

Definition: isolated pawns on e2 and e3,

or d2 and d3

as easily recognised, the pair of central

isolated pawns on d2 and d3 are a major
liability.
Because of them, the white pieces are not
only undeveloped, but very difficult to
d2 and d3 are such a pair develop, too. The d3 pawn blocks the
white bishop on e2, its counterpart on d2
Value: large penalty, -30cps, only for the does the same with the c1 bishop, but even
mg more stringently, as, in order for the
bishop to develop in the center, the d3
Additional information: the penalty is pawn should move first, and then the d2
due not so much because of the structural one. This takes a lot of time. The white
weakness of such pawns, but rather queen can not develop along the d file, too.
because of their mg paralytical As the bishop on c1 blocks the access of
dysfunction. As such pawns are central, the white rook on a1 to the c file, it is
the pawn on its 2nd rank will block the certainly not an overstatement to say that
friendly bishop on the same side of the more or less the entire white queen side is
board on its home square, while at the paralysed.
same time blocking the development of the From that point of view, the one pawn
friendly queen, positioned on the same material deficit of black is more than
file, too. With these 2 pieces blocked, the compensated by its superior development.
rest of the side's pieces will be blocked
too, so this will have a very negative
reflection on general piece development as
a whole.
In the early middlegame, with lots of
available piece attacks upon the king, that
might prove decisive.

89
 Vertically isolated pawn

Definition: pawn that does not have other

own pawns on the same rank, on the rank
in front of it and on the rank behind it on
both adjacent files, while still having at
least one other own pawn on adjacent files
on ranks different from the specified above

pair of isolated central pawns on the side

where the own king is are sometimes even
more negative, as this will have immediate
bearing on king safety

h5, g3, f5 are all vertically isolated pawns;

a6 is another one

Value: penalty, valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 -21 -22 -23 -24 -24 -23 -22 -21
6 -17 -18 -19 -20 -20 -19 -18 -17
5 -13 -14 -15 -16 -16 -15 -14 -13
4 -9 -10 -11 -12 -12 -11 -10 -9
3 -5 -6 -7 -8 -8 -7 -6 -5
having the pawns blocked by an enemy 2 -1 -2 -3 -4 -4 -3 -2 -1
pawn or minor piece is even nastier, as the 1 0 0 0 0 0 0 0 0
pawns will be completely immobilised, a b c d e f g h
thwarting friendly piece development for a
longer time. vertically isolated pawn penalty(mg)
Black is winning with utmost ease.

Frequency: infrequent

90
8 0 0 0 0 0 0 0 0 a compact structure by pushing g3-g4, as
7 -22 -23 -24 -25 -25 -24 -23 -22 g4 will be met by a f5-g4 capture
6 -18 -19 -20 -21 -21 -20 -19 -18
5 -14 -15 -16 -17 -17 -16 -15 -14 Frequency: very frequent
4 -10 -11 -12 -13 -13 -12 -11 -10
3 -6 -7 -8 -9 -9 -8 -7 -6
2 -2 -3 -4 -5 -5 -4 -3 -2 Squeezed pawn
1 0 0 0 0 0 0 0 0
a b c d e f g h
Definition: pawn, that is not defended,
with enemy pawns on the same file, one
vertically isolated pawn penalty(eg) rank in front of it, and one rank behind it
Additional information: vertically
isolated pawns are one of the many types
of undefended(weak) pawns. They are due
penalty, though relatively small, because:
- they are weak(undefended), easily
attackable and capturable by enemy pieces
- largely inflexible, although some
possible pushes by such pawns or other
own pawns would still lead to the building
of a compact pawn structure, most will
not, especially when the other own pawns
on adjacent files are further apart in terms
of ranks

On a range of occasions, bridging the gap

to build a compact structure is even
practically impossible, depending on
black e4 is such a pawn. It is squeezed
enemy pawn control, see for example this
between the pair of white e3 and e5 pawns
one:
on the same file on adjacent ranks.
white e5 pawn, on the other hand, is not a
squeezed pawn, as, although conforming
to the same conditions, it is defended by
the f4 pawn.

Value: penalty, -10cps, both for the mg

and eg

Additional information: the penalty is

due, because such pawn is more vulnerable
than usual, with enemy pieces having
easier access to it, and own pieces a more
difficult task in supporting it, because of
the 2 enemy restricting pawns.
For example, on the diagrammed position,
a black rook would not be able to defend it
on the file the pawn is, as the e5 white
even though only 2 ranks apart, it is pawn will prevent that.
impossible for the g3 pawn to span the
distance to the h5 friendly pawn and build

91
even if not isolated, friendly pawns on doubled pawn on b4
adjacent files will have hard time (no matter what the other possible
defending it, too, as, in order to do that, positional factors might be, it seems
they will first have to pass through the clumsy and unappealing both in the mg
enemy sentinel behind it. and eg)
above, f7-f5, trying to support e4, might be
met with ef6, and the pawn is still Value: penalty valid in terms of psqt
unsupported.

Frequency: infrequent 8 0 0 0 0 0 0 0 0
7 -38 -18 -23 -28 -28 -23 -18 -38
6 -36 -16 -21 -26 -26 -21 -16 -36
5 -34 -14 -19 -24 -24 -19 -14 -34
Doubled pawns 4 -32 -12 -17 -22 -22 -17 -12 -32
3 -30 -10 -15 -20 -20 -15 -10 -30
Definition: a pawn that has another own 2 0 0 0 0 0 0 0 0
pawn on the same file on a less advanced 1 0 0 0 0 0 0 0 0
a b c d e f g h
rank
(of course, it is a matter of convention
whether to define doubled pawns in terms doubled pawn penalty psqt(mg)
of the more advanced or the less advanced
8 0 0 0 0 0 0 0 0
pawn, here we will follow the first option,
7 -48 -23 -30 -38 -38 -30 -23 -48
although the second one is perfectly
6 -46 -21 -28 -36 -36 -28 -21 -46
reasonable too, it all depends on how you
5 -44 -19 -26 -34 -34 -26 -19 -44
look at the board and how you estimate -42 -17 -24 -32 -32 -24 -17 -42
4
your other evaluation features) 3 -40 -15 -22 -30 -30 -22 -15 -40
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

doubled pawn penalty psqt(eg)

Additional information: doubled pawns

are the easiest to recognise on the board,

92
even by complete newbies. You just have is due to the fact that, practically, the side
to see the one after the other on the same with the doubled pawn plays with a pawn
file pattern, but the ugly structure is even less, as undoubling such a pawn is
more salient. extremely difficult or practically
Humans definitely estimate doubled pawns impossible to achieve, even in the long
better than even top engines, but I guess term
both humans and engines alike largely
underestimate what is hidden in this
concept and its various implementations.
One can score doubled pawns in at least a
dozen specific situations, but we will
concentrate here on just the most
important ones.

Doubled pawns get their well-deserved

penalty due to a variety of reasons, among
which the most salient ones are:
- the doubled pawn thwarts the advance of
the less advanced pawn behind it
- in case the doubled pawn is also a pawn-
blocked one, above feature is even more
negative, thus rendering both own pawns
awkward
- in the highly indicative case of a doubled blocked doubled pawn on d5
pawn blocked by an enemy one with the well, such a pawn simply can not advance
other own pawn placed on the rank to try undoubling with the help of own
immediately behind the doubled pawn, the pieces, so it is a bigger negative(a few cps,
immobility weakness of the doubled pawn maybe -5 or -6 in the mg, -8 in the eg)
and its behind-walker are exaggerated to a
point that makes them a tremendous
liability
- in many cases, if not defended, doubled
pawns are of course also easily attackable
- in the extremely negative case that the
doubled pawn is simultaneously an
isolated one, even adding the doubled and
isolated penalties for the pawn will not be
sufficient to completely capture the
negativity of the phenomenon, so in this
case an additional over-penalty is due
- a large additional over-penalty is also
very much appropriate in the specific case,
when the doubled pawn is opposed by an
enemy pawn and there is symmetrical
pawn placement of both own and enemy
pawns on the 2 adjacent files(the single blocked doubled pawn on f4 with its less
adjacent file in case the doubled pawn is advanced counterpart on the rank
an edge a or h file one), i.e. both files are immediately behind it, and immobile
open ones, one is open and the other one (this is a serious penalty, as both f4 and f3
closed, or both files are closed; the penalty pawns are immobile, more vulnerable

93
targets, more durable liabilities; -8cps extremely difficult to undouble, extremely
additional penalty in the mg, -12cps in the difficult to advance, and more or less
eg, would be quite appropriate) worthless, even in the very long run. I
would assign some -20cps mg penalty, -
40cps eg penalty for such a pawn)

Frequency: frequent

Distance between doubled pawns

Definition: available squares between the

more advanced and the less advanced
doubled pawn

doubled isolated pawn on c4

well, this is a major weakness, due further
over-penalty, maybe some -15cps or so in
the mg, some -22cps in the eg; reasons:
- pawn is even more vulnerable to
opponent pieces' attacks
- pawn is even more difficult to undouble

3 available squares between the b2 and b6

doubled pawns, one available square
between the d2 and d4 doubled pawns, and
zero available squares between the g2 and
g3 doubled pawns

Value: small bonus, assigned in terms of

the square distance, equal for mg and eg

- 2cps, for one available square

- 4cps, for two available squares
- 6cps, when the squares are three
- 8cps, for 4 squares
symmetrical doubled white pawn on h5;
symmetrical doubled black pawn on c4 Additional information: the bonus is
(well, as you immediately spot for given for 2 reasons:
yourselves, this is a major weakness; the - with bigger distance between the pawns,
side with the doubled pawn effectively the less advanced doubled pawn, the pawn
plays with a pawn less, this pawn is

94
going behind, will have more free
available pushes
- more advanced pawns, already having
crossed the center line, in spite of being
weak, already gain space and are less of a
liability

As easily seen on the diagrammed

position, the most awkward constellation
is that of the g2 and g3 doubled pawns,
with the pawn going behind, g2, unable to
move.

the h4 pawn restricts the black g6 pawn

Value: small bonus, 6cps in the mg, 8cps

in the eg, for the restricting pawn

Additional information: the bonus is

given for the obvious very negative
condition, making the doubled pawn
unable to move forward without severely
compromising the pawn structure, and thus
less valuable.

On the diagrammed position, if g6 pawn

the c6 doubled pawn is a strong passer, so advances, after hg5 fg5, a doubled isolated
its weakness is not felt at all. pawn will appear on g5, while, if f6 pawn
The h2 and h3 doubled pawns, however, advances, the doubled g6 pawn will lack
are very weak, with both immobilised by the support of a friendly pawn to do a
the black blocking h4 pawn on adjacent successful push, remaining logically
squares. immobile until a support from a friendly
piece.
Frequency: frequent The condition is more severe, as the
doubled pawn is not advanced.

Restricting enemy doubled pawn on its Frequency: frequent

3rd rank

Definition: pawn on the 4th rank, Blocking an enemy doubled pawn on its
controlling the square in front of enemy 3rd rank
doubled pawn on its 3rd rank, provided
that square is empty Definition: pawn on the 5th rank, blocking
an enemy doubled pawn on its 3rd rank

95
the g5 white pawn blocks the black g6 f3 and g4 are such a pair
pawn
Value: sufficiently large penalty, -20cps,
Value: bonus, 15cps, both for the mg and both for the mg and eg
eg, for the advanced blocking pawn
Additional information: the penalty is
Additional information: the good bonus due for the obvious structural deficiency of
is given for the almost permanent doubled the pair, it is even more immobile than 2
and immobile condition of the doubled separate doubled pawns on different
pawn until the opponent blocking pawn is portions of the board, as the adjacent pair
possibly captured. and the friendly pawns going behind them
As easily recognised on the diagrammed are in each other's way. Besides, the
position, if the f7 black pawn goes to f6, awkward non-standard phalanx is easily
and then captures the blocking g5 pawn, a stopped by a significantly smaller number
tripled very weak pawn will arise on g5 for of opposing pawns, 3, or even just 2.
black, while, after an f7-f5 push, the Also, the pair will be very clumsily placed
doubled pawn condition will remain for any friendly piece wishing to play an
unchanged. active role in the region.

The bonus is large, as the doubled pawn is 2 separate doubled pawns penalties will
immobilised close to its home rank. not be sufficient, the above-mentioned
weaknesses necessitate an ad-hoc over-
Frequency: frequent penalisation.

Frequency: infrequent
Pair of doubled pawns on adjacent files

Definition: a doubled pawn, with another Tripled pawn

own doubled pawn on adjacent file
Definition: a pawn that has 2 other own
pawns on the same file that are both less
advanced

96
 promotion, and even passers, whose
squares to promotion would be sufficiently
controlled by opponent pieces, could be
defined as backward; the degrees of
backwardness, however, would be
extremely different in all the possible
cases, ranging from couple of percent
backward to almost a 100 percent
backward.
Here, we will discuss only the most salient
features involving backwardness, as, even
for a master specialist in backward pawns,
it is far from an easy task to make perfect
sense how to specifically define all the
backward conditions without going into an
unimaginable extent of detail. One of the
tripled pawn on e5 reasons for this is that square control is
(usually, tripled pawns will be also dependent on the strength of the different
isolated, as such pawns come from pieces attacking the particular square, and
adjacent files) doing a full analysis of all piece attacks on
all possible squares is currently impossible
Value: penalty, -30cps mg, -30cps eg for top humans and top engines alike.

Additional information: of course, an

over-penalty above that for the simple Standard backward pawn
doubled pawn is due because:
- tripled pawns are even uglier, even more Definition: a pawn defending another own
awkward and clumsier pawn, blocked by an enemy pawn, with no
- extremely difficult to untriple and also other own pawns on adjacent files on the
extremely vulnerable to enemy pieces' same rank as the backward pawn or on less
attacks, as such pawns will frequently be advanced ranks
isolated too

Frequency: infrequent

Backward pawns

Backward pawns are so plentiful, that at

least 30 to 50% of all available pawn
features might have something to do with
them. In fact, backwardness in itself means
that the advance of a pawn, no matter its
rank and location, might be stopped by an
opponent pawn or any other piece, so that
its further movement would lead to its
loss. Under such a condition, almost any
pawn that has enemy pawns on adjacent d3 is a standard backward pawn above
files that would stop its march to

97
Value: Penalty, valid in terms of psqt 8 0 0 0 0 0 0 0 0
(and it makes very much sense to split 7 0 0 0 0 0 0 0 0
tables into opposed/unopposed flags, as 6 0 0 0 0 0 0 0 0
unopposed standard backward pawns are 5 -5 -6 -7 -8 -8 -7 -6 -5
easier targets to enemy heavy pieces along 4 -17 -30 -30 -40 -40 -30 -30 -17
the semi-open files those pawns are on) 3 -25 -35 -35 -45 -45 -35 -35 -25
2 -30 -40 -40 -50 -50 -40 -40 -30
8 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0 a b c d e f g h
6 0 0 0 0 0 0 0 0
5 0 0 0 0 0 0 0 0 backward unopposed pawn psqt(eg)
4 -10 -20 -20 -30 -30 -20 -20 -10
3 -15 -25 -25 -35 -35 -25 -25 -15 Additional information: standard
2 -20 -30 -30 -40 -40 -30 -30 -20 backward pawns get their well-deserved
1 0 0 0 0 0 0 0 0 penalty due to a variety of reasons:
a b c d e f g h - the pawn itself is undefended/easily
attackable
backward opposed pawn psqt(mg) - on many occasions, if this pawn is
captured, and the other own pawn it
8 0 0 0 0 0 0 0 0 defends is not supported by other friendly
7 0 0 0 0 0 0 0 0 pawn, it will immediately get weak too
6 0 0 0 0 0 0 0 0 - as said, most of the penalty goes for the
5 0 0 0 0 0 0 0 0 fact that such a pawn is not able to
4 -15 -25 -25 -35 -35 -25 -25 -15 realistically advance without being lost;
3 -20 -30 -30 -40 -40 -30 -30 -20 this means the side with such a pawn has
2 -25 -35 -35 -45 -45 -35 -35 -25 less resources to influence the game
1 0 0 0 0 0 0 0 0 - standard backward pawns are extremely
a b c d e f g h
damaging on lower ranks, as having low-
mobility pawns on the home rank or close
backward opposed pawn psqt(eg) to it is equivalent to a sort of receiving a
cramped position on the section of the
8 0 0 0 0 0 0 0 0
board where those pawns are, with the
7 0 0 0 0 0 0 0 0
additional negative of not being able to use
6 0 0 0 0 0 0 0 0
such pawns for attacking purposes by
5 -3 -4 -5 -6 -6 -5 -4 -3
-12 -25 -25 -35 -35 -25 -25 -12
legitimately advancing them
4
3 -18 -30 -30 -40 -40 -30 -30 -18
2 -25 -35 -35 -45 -45 -35 -35 -25 Frequency: very frequent
1 0 0 0 0 0 0 0 0
a b c d e f g h
Twice backward pawns
backward unopposed pawn psqt(mg)
Definition: a backward pawn the square in
front of which is simultaneously attacked
by 2 enemy pawns, both of which are
blocked by own pawns

Note: it is extremely curious that even top

humans do not make very extensive use of
this useful concept, and top engines have
an extremely difficult time implementing
and recognising the concept either.

98
Seemingly, this feature is so positional, 8 0 0 0 0 0 0 0 0
involving such a long sequence of moves 7 0 0 0 0 0 0 0 0
until its value is recognised, coming to 6 0 0 0 0 0 0 0 0
fruition, that many would even entirely 5 0 0 0 0 0 0 0 0
disregard it. 4 0 -35 -45 -55 -55 -45 -35 0
3 0 -40 -50 -60 -60 -50 -40 0
2 0 -45 -55 -65 -65 -55 -45 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

twice backward opposed pawn psqt(eg)

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 0 0 0 0 0 0 0 0
5 0 -20 -25 -30 -30 -25 -20 0
4 0 -35 -45 -55 -55 -45 -35 0
3 0 -40 -50 -60 -60 -50 -40 0
2 0 -45 -55 -65 -65 -55 -45 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

twice backward unopposed pawn psqt(mg)

d3 now is already twice backward,
involving a significantly bigger penalty 8 0 0 0 0 0 0 0 0
(as you see, moving forward is altogether 7 0 0 0 0 0 0 0 0
impossible, even with the significant help 6 0 0 0 0 0 0 0 0
of own pieces, making the twice backward 5 0 -25 -30 -35 -35 -30 -25 0
pawn almost entirely useless) 4 0 -40 -50 -60 -60 -50 -40 0
3 0 -45 -55 -65 -65 -55 -45 0
Value: large penalty, valid in terms of psqt 2 0 -50 -60 -70 -70 -60 -50 0
and opposed/not opposed flags 1 0 0 0 0 0 0 0 0
a b c d e f g h
8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0 twice backward unopposed pawn psqt(eg)
6 0 0 0 0 0 0 0 0
5 0 0 0 0 0 0 0 0
4 0 -30 -40 -50 -50 -40 -30 0 Additional information: twice backward
3 0 -35 -45 -55 -55 -45 -35 0 pawns are due their penalty because:
2 0 -40 -50 -60 -60 -50 -40 0 - they are completely immobile, which
1 0 0 0 0 0 0 0 0 would translate to the side having such a
a b c d e f g h pawn practically playing without it; it is
difficult to find a bigger waste of
twice backward opposed pawn psqt(mg) positional resources in chess, at least what
concerns pawn evaluation
- undefended and easily attackable; in case
such a pawn is destroyed, any other of the
2 own pawns defended by the twice
backward pawn, if not supported by a
second pawn, would immediately become
undefended too, which is exceptionally

99
negative when both would be supported of cramping than if a black pawn wedge
only by it was placed on d3)
- very long term liability; in order for such
a pawn to disappear from the board with
advantageous consequences for the side
having it, this side should have weighty
tactical resources at its disposal, and
tactical resources, as everyone knows, are
not always readily available
- on a range of occasions, under specific
conditions, for example when such a pawn
is part of the own king shelter, or a central
one, the burden on the side having it
increases tremendously, up to a point to
quickly lose the game
- not infrequently, a central d3 or e3 twice
backward pawn would lead to a complete
closing of the position with inevitable
advantage for the opponent side, as the
opponent side will have a pawn more on well, imagine this situation: pawn numbers
one of the wings, getting additional for both sides are equal, but, as d3 is twice
storming resources, while at the same time backward in the center, white practically
the twice backward side will be devoid of plays with a pawn less, d3-d4 break in the
realistic counterplay, bearing in mind that center to attain counterplay is impossible,
the strongest counterplay ever is the one in and black has a pawn more on the king
the center side to start a mighty king-side attack by
pushing g7-g5, h7-h5, etc.

Frequency: infrequent

Twice backward feature

Definition: pawn, that is not twice

backward, defending an own pawn,
blocked by an enemy pawn, with the
square in front of it controlled by 2 enemy
pawns, and no own pawns on the same
rank or less advanced ranks on adjacent
files.
Otherwise, simply, a backward pawn, that
is not twice backward, with the square in
front of it controlled by 2 enemy pawns.
twice backward pawn on the 2nd rank is
even worse
(by definition, under such a condition, the
white position would be cramped, no
matter the disposition of forces on other
wings; this is even more negative in terms

100
 a pawn is a central one, or part of the own
king shelter. In such cases, the full center
gets immobilised, simulating closedness,
which will have beneficial effect on the
opponent side, if attacking, as it will have
more time to regroup and bring new
resources supporting the attack. Or,
alternatively, the king shelter is less
flexible and much more prone to enemy
attacks, sometimes of a slow nature.

It is necessary to consider this pawn

feature apart from standard backward
pawns, as the condition is much more
severe. It is also necessary to make a
distinction with a full twice backward
d3 is a twice backward feature. It is not a pawn, as this one already gets its separate,
twice backward pawn(which will defend 2 much higher penalty. The feature is
own pawns at the same time), defends an frequent and important, so it will be a big
own pawn, c4, and the square in front of it, mistake not accounting for it.
d4, is controlled by 2 enemy pawns, c5
and e5.

d3 is a twice backward feature in the

center of the board that pretty much loses
f2 is another twice backward feature, this the game. Because of its nature, the center
time part of the king shelter as a whole is completely immobilised, so
black has all the time in the world to start a
Value: sufficiently large penalty, -25cps in gradual kingside attack with g7-g5, Rf7-
the mg, -15cps in the eg, over the one for a g7, etc., slowly building up pressure. That
standard backward pawn swings the balance of forces in a decisive
way.
Additional information: the penalty is Some engines or humans might think
obviously due for the peculiar almost white has the advantage because of its
complete immobilisation of the pawn. The more prolific pawn shelter, as well as the
condition is especially relevant, when such good b5 outpost square for the white

101
knight on c3, but that is far from being the Semibackward pawn on the 2nd rank
case.
So that, failing to consider similar subtle Definition: a pawn exclusively on the 2nd
evaluation features might sometimes give rank, that is defending aligned, with the
a fully distorted picture of the position. own pawn defended by it blocked by an
enemy pawn

there is no other option but for white to

lose the game, after a bishop sacrifice on c2 is a semibackward pawn on the 2nd
h4, followed by bringing both rooks to the rank (c2 is defending aligned, and b3 is
king side, Nf6-h7-g5-f3, etc., with a rout, blocked by b4)
but some engines or humans might think it
is white who has the advantage, due to the Value: penalty, -15cps in the mg, -10cps
missing black pawn shelter, the advanced in the eg
white queenside pawns and somewhat
better development. Additional information: the penalty is
Of course, this is not so, and the main due to following factors:
reason for black's substantial positional - usually, the square in front of such a
advantage is the completely immobilised pawn would be additionally controlled by
white pawn shelter, in the form of the f2 enemy pieces, which would render this
pawn, constituting a twice backward pawn effectively fully backward; the pawn
feature. Because of this shelter is simply too unadvanced and chances are
inflexibility, black has all the time in the enemy pieces would already have reached
world to slowly increase pressure, bringing this portion of the board earlier
up additional attacking resources to the - even if not so, a single push could be met
king side of the board. by capture, while a double push by an en
passant capture, which would mean the
The mg bonus is substantially higher than building of a particular pawn structure
the eg one, precisely because of the above- largely dependent on the discretion of the
mentioned features, encountered opponent; this is especially sensitive in
exclusively in the mg. cases involving the king shelter

Frequency: frequent Frequency: very frequent

102
 Unbackwarded pawn weaknesses that would annul drawing
chances.
Definition: a pawn on the 4th rank,
defended by an own pawn, which in turn is
blocked by an enemy pawn

well, why above position, the Chech

Benoni, arising with a bit of
transformations after for example 1.d4 c5
e4 is an unbackwarded pawn 2.d5 e5 3.c4 d6 4.Nc3 g6 5.e4 Bg7 6.Bd3
(as you easily see, it simply can not Ne7 gives black complete equality, which
possibly be made backward by the enemy both top engines and many humans fail to
d4 pawn, as it has already moved past the recognise: c5 and e5 black pawns are
influence square of d4; this means, you unbackwarded, they can not become weak
guarantee yourself easier life) backward pawns, it is impossible for white
to break with c4-c5 on the queenside, as c4
Value: bonus, 10cps in the mg, 5cps in the is blocked, while at the same time black
eg could easily draw by placing all black
pawns on dark squares, f6,g5,h6, achieving
Additional information: unbackwarded symmetry and building an impregnable
pawns get their quite deserved small value fortress; if white does not push f2-f4, after
for the fact that such a pawn has already f7-f5-f4 black can even get better
moved past the control of the enemy
sentinel pawn on the same rank next to it,
so it practically can not become backward,
at least not on low 2nd and 3rd ranks. This
is an important asset, though many humans
tend to disregard it, and what concerns
engines, they have almost no clue about
such pawns, unless there is something
tactical to see alongside.
Such pawns are extremely useful in the mg
with larger closed structures, both in trying
to win the game using a wing attack and in
attempting to draw, resorting to
closing/blocking as many files as possible,
while getting rid of any possible backward

103
 d5 is the backwardmaker, and e7 is the
backward pawn

same situation: this favours white, no

matter how much surprised some humans,
and especially some engines, might be. c4
and e4 are unbackwarded, central at that, c5 is the backwardmaker, and b7 is the
the position is largely closed and, no semi-backward pawn
matter that white significantly lags behind
in development, f2-f4, creating a nice Backwardmakers might be especially
compact structure, involving useful with conceptual definitions.
chains/storming pawns at that, should
easily decide the game.
Unopposed backward-maker on the 5th
rank
Backwardmakers
Definition: pawn that is not opposed, not a
A backwardmaker is any pawn that makes passer or a potential passer, takes the 5th
an enemy pawn backward, semi-backward rank, with an enemy pawn on the 7th
or otherwise backward. rank(2nd rank from the opponent point of
view) on adjacent file

104
well, b5 is an unopposed backwardmaker e6 is an unopposed chain backward pawn
on the 5th rank
Value: penalty, -15cps, awarded only for
Value: bonus, 15cps in the mg, 10cps in the mg
the eg
Additional information: this is a strictly
Additional information: the bonus is mg feature, with great effect on the game,
given because: as everything central. Penalty is given
- although not strictly backward, the because, although such a pawn is
enemy pawn on its home rank can not defended, not vulnerable, it still can not
move advantageously, without being lost advantageously advance along the central
or creating further weaknesses file to break open the game. As you can
- even if the enemy pawn is not captured easily see from the diagrammed position,
upon advancing, the backwardmaker might e6-e5 is impossible to play and, an attempt
transform into an advanced passed to break with f7-f6 and e6-e5 is frequently
pawn(see the diagrammed position) thwarted by a predominant control of
white pieces upon the e5 square, for
example Nf3 will often be present, and a
Central unopposed chain backward white rook on e1 active on the semiopen e
pawn file.

Definition: exclusively, d3 or e3 pawns Frequency: frequent

that are unopposed, with the condition that
such a pawn is defended by a pawn and
simultaneously defends another own pawn Central backwardmakers
along the same diagonal, which in turn is
blocked by an enemy pawn Definition: white pawn on e5, black
pawns on e6,f7,g7, black king on e,f,g or h
file, or, on the queen side, white pawn on
d5, black pawns on d6,c7,b7, black king
on d,c,b or a file

105
 variations are usually so deep, that
calculating everything would be quite
difficult even with the mighty help of
pattern recognition. Even top engines, too,
not to mention the rest, have generally a
hell of a time with the feature, mostly
completely ignoring it. The reason should
be lacking refined evaluation, but also
extreme depth of the lines, inaccessible to
even the best searchers.

The very-well deserved bonus is dispensed

for the following rather weighty reasons:
- the enemy pawn on adjacent file to the
backwardmaker is a semi-backward one,
and, as it constitutes part of the enemy
central backwardmaker on the king side king shelter, the weakness is further
highlighted
- having a semi-backward pawn of the
king shelter basically means the shelter
will be inflexible, sometimes, in order to
defend, a shelter pawn should move
forward, and this will largely depend on
the discretion of the backwardmaker, that
has always the option of capturing;
frequently, capturing will lead to severely
weakening the pawn shelter, with isolated
pawns left behind and also the number of
shelter pawns decreasing, not moving the
backward pawn at all, on the other hand,
will hardly be tolerable in the long run
- as the backwardmaker is a central pawn,
this presumes by definition a more closed
character of the position, meaning the
central backwardmaker on the queen side attacker will have more time to regroup its
pieces
Value: sufficiently large bonus, 30cps in
the mg, 10cps in the eg

Additional information: this is one of the

most important terms at all. Its relevance is
so big, and it is so frequently encountered,
that excluding it from any evaluation
framework, human or engine alike, would
be simply a gross negligence.

Humans mostly should handle this purely

theoretically sufficiently well, but, in
actual fact, that is far from the case in a
range of situations, as the associated

106
let's imagine now, what will happen, if after 1.e4 e6 2.d4 d5, white can continue
black plays f7-f5, or f7-f6, trying to get rid with 3.e5, reaching above position.
of the clamp. White has the option of Do you recognise the pattern in the form
capturing ef6, and after gf6, the black of the e5,e6,f7,g7 pawns? It is already
shelter will shrink to only 2 pawns(f6 and there, on the 3rd move, in a very popular
h6), with h6 becoming isolated. In case opening. Of course, this might not be the
black captures with a piece on f6, the wisest kind of play, as white will
shelter will again shrink to 2 pawns(g7 and compromise on development, but is still
h6), with the e6 pawn also possibly strong.
becoming isolated.
So, in each case, the shelter will suffer
enormously.

This term has a tremendous theoretical

importance. It is encountered, starting
from the very first moves, in a great range
of openings, and, if understood to the
fullest, could become even more frequent
phenomenon.
To start with, let us take the French as an
example.

or, in the same French, emphasising

development, with a better piece
coordination, white might choose the
McCutcheon, with 3.Nc3 Bb4. Again,
white is faced with a choice, what to do in
the center. Recognising our strong central
pattern, the natural option would be 4.e5,
which is indeed the best move, also

107
theoretically and statistically proven. Still, Top engines, of course, completely
many humans will shun away from it, misunderstand and misplay the variation.
while, even the top of the top of engines Most of them will still assess above
will almost exclusively play ed5 ed5, position as very favourable for white, but
exchanging in the center and losing all of of course, black is winning. As the
white's advantage. associated lines are very deep, engines
How can such engines be trusted? basically see nothing and rely on their
positional evaluation, which is far from
Another very frequent opening occurrence perfect and, in many cases, like this one,
of the term could happen in the English rudimentary.
Opening, after 1.c4 e5 2.Nc3 Nf6, in case Winning is pretty much straightforward:
white continues with e3 instead of e4, black continues with slow attack on the
giving black the opportunity to gain space king side, pushing pawns there, and
advantage in the center and clamp white's gradually transferring pieces to this focal
king shelter by advancing e5-e4. point, including the ones on the queen
side. As the position largely carries a
closed character, emphasised by the e4
central backwardmaker, black has all the
time in the world for regrouping and
coordination. White, on the other hand,
can do almost nothing, as the white shelter
is inflexible, and attempting to break free
with f2-f3 or f2-f4 will easily backfire,
creating multiple weaknesses.

Examples like that are rife, but there is no

need to illustrate them all. What is more
important is the pattern recognition.
Precisely because of this term, the French
is a bad opening for black, as widely
recognised by modern top players, so one
should choose one's openings very
in spite of the big development advantage carefully.
white enjoys, black has already a winning
position. And the main reason for this is The extreme importance of the central
the familiar central pawn pattern in the backwardmaker feature is also due to the
form of the e4,e3,f2,g2 pawns. The central fact that it starts appearing on the board
e4 black backwardmaker is having a with the very first moves, thus influencing
cramping effect upon the entire white king the entire game.
side and renders the white shelter
inflexible. Frequency: very frequent
I am not very certain about humans, but,
judging from the theoretical popularity of
the English Opening lines, involving e3 Distant backward pawn
instead of e4, humans mostly fail to
understand the relevance of the feature, Definition: pawn on the 2nd rank, with no
even after decades of analysis. Mainstream enemy pawns on the 3rd and 4th ranks on
chess textbooks still do not recommend the same file, with another own pawn on
playing 3.e4 instead of 3.e3 in the the 4th rank on adjacent file, that is
mentioned line! blocked by enemy pawn, and no other own

108
pawns on the 2nd and 3rd ranks on the Backward long chain pawn blocked
other adjacent file condition

Definition: long chain pawn, that is not

blocked by an enemy pawn, with the pawn
it defends and the pawn, defending it, part
of the same chain, both blocked by enemy
pawns

c2 is a distant backward pawn. The

squares in front of it on the same file are
not occupied by enemy pawns, on the 4th
rank on adjacent file there is another own
pawn that is blocked by enemy pawn, b4,
and on the 2nd and 3rd ranks on the other
adjacent file there are no friendly pawns, c3 is such a pawn. It is a long chain pawn,
that could support its advance. part of the b2-c3-d4 long chain, not
blocked by an enemy pawn, and both the
Value: penalty, -10cps, both for the mg pawn it defends, d4, as well as the pawn
and eg defending it, b2, part of the same chain,
are blocked by enemy pawns, d5 and b3
Additional information: the penalty is respectively.
due for the obvious backwardness of the
pawn. On c3, it would be a fully-fledged
backward pawn, but, even on c2, one
square less advanced, its backward
condition is evident, though not that much
severe. The pawn could advance once,
becoming a full backward pawn, but not
twice, on c4, where it will be lost by the
b5-c4 capture, like any other backward
pawn.
So, c2 is indeed a backward pawn, with
less prominent character.

Frequency: very frequent

g4 is another such pawn, this time

109
 on the 4th rank of the backward pawn would be possible,
with both Rc8 supporting that push on an
Value: small penalty, -8cps, both for the x-ray and Qf8 directly supporting it. Now
mg and eg this push is simply banned, at least for the
time being, and that gains white valuable
Additional information: this is not a full time to achieve different goals.
standard backward pawn in any Similar effect is achieved when such a
conceivable way, but, although it is a square is attacked by a bishop.
defended, strong pawn, its partial
backwardness is obvious. Indeed, as easily
seen on above-posted diagrams, any Root pawn
advance of these pawns will be met by
their loss. Definition: the least advanced undefended
So, the feature is real, the backward pawn, part of a chain, short or longer one
condition quite evident, but, as the pawn is
a strong one, less vulnerable to enemy
attacks, the penalty is naturally smaller.

Frequency: infrequent

Minor piece controlling the square in

front of enemy backward pawn

c3 is the root pawn, or root, of the c3-d4-

e5 longer chain.
h5 is the root of the h5-g4 short black
chain.

Value: when not backward, root pawns

only represent the bigger asset of the chain
formation, and therefore should not be
penalised
Nd3 controls/attacks the square in front of
black c6 backward pawn Frequency: very frequent

Value: bonus, 8cps, mg and eg

Attacking root pawns
Additional information: well, of course,
minor piece control of such a square could Definition: any non-pawn and non-king
very much decide how backward the pawn piece attacking an enemy root pawn
really is. If Nd3 was not present on the
diagrammed position, c6-c5 push to get rid

110
Value: bonus, 10cps, both for the mg and When the black queen captures the g3 root
eg pawn, the h4 pawn becomes undefended.

Additional information: the bonus is Frequency: frequent

given for the obvious condition that, when
such a root pawn is attacked and
successfully destroyed, not only it Double root pawn
perishes, but another enemy pawn, the one
it used to defend, automatically becomes Definition: an undefended pawn
undefended too. defending 2 other own pawns at the same
time

when the black bishop captures the c2 root

pawn, the b3 pawn becomes automatically f2 is a double root pawn
undefended and vulnerable (in this particular case being also part of
the white king shelter)

Value: Penalty, valid in terms of psqt

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 0 -9 -10 -11 -11 -10 -9 0
5 0 -8 -9 -10 -10 -9 -8 0
4 0 -7 -8 -9 -9 -8 -7 0
3 0 -15 -18 -23 -23 -18 -15 0
2 0 -20 -25 -30 -30 -25 -20 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

double root pawn psqt(mg)

when the black knight captures the d4 root

pawn, the c5 pawn becomes undefended.

111
8 0 0 0 0 0 0 0 0 central squares, either with the c4, or f4
7 0 0 0 0 0 0 0 0 pawns. Friendly pawns placed on d5 or e5
6 0 -9 -10 -11 -11 -10 -9 0 on the 5th rank within the enemy half of
5 0 -8 -9 -10 -10 -9 -8 0 the board are pretty much irrelevant here,
4 0 -7 -8 -9 -9 -8 -7 0 as this has already more to do with space
3 0 -8 -10 -13 -13 -10 -8 0 advantage.
2 0 -10 -12 -15 -15 -12 -10 0 Direct pawn control within our evaluation
1 0 0 0 0 0 0 0 0 framework is mainly seen by the relevant
a b c d e f g h pawn, defended pawn, aligned pawn, etc.
psqts, giving substantial bonus points for
double root pawn psqt(eg) such pawns on d4 and e4, while indirect
square control is provided for by terms like
Additional information: double root semi-central pawns attacking empty
pawns should be penalised in view of the central squares, central bind and others.
following factors: Of course, minor or other pieces
- the pawn itself is weak, easily attackable controlling the center simultaneously with
and destroyable own pawns also play a substantial role in
- if captured, the 2 other pawns, defended center control, and are mirrored in a bunch
by it, simultaneously become undefended of associated features.
and easy prey to enemy pieces
- this particular condition also means that
the square in front of the double root pawn Central piece attacks
is pawn-undefended, a big disadvantage,
especially with less advanced pawns Any non-pawn piece attacking an enemy
piece or pawn positioned on one of the
Frequency: frequent central squares gets the following bonus:

- 15cps for the mg, 8cps for the eg, if the

enemy piece is on d4,e4,d5 or e5
Control of center - 8cps for the mg, 4cps for the eg, if the
enemy piece is on
c3,d3,e3,f3,c4,f4,c5,f5,c6,d6,e6 or f6(so-
Control of center is one of the weightiest called extended center)
features available. Fischer said of central
control: 'This is like hitting the ball with Reason is simple: a possible capture will
the bat'. When speaking about the center of place the attacker on a central square, and
the board, we primarily mean the 4 the center in chess is all-important. Values
central-most squares, d4,e4,d5 and e5, the are not so big, as this is of largely tactical
so-called focal center. nature, and tactics in chess are usually
Control of center is more or less very difficult to account for with general
synonymous with friendly pawns exerting rules, in case you want to associate tactics
that control. So, when we speak of control with positional factors. Pawns are
of center, we primarily mean pawns. excluded from the set of attackers, as this
Control of center basically has 2 forms: would unnecessarily complicate the
direct control and indirect square control. equation with a number of contradictory
Direct control will mean placing pawns on levers.
one of the 2 central squares on the 4th
rank, d4 and e4, while indirect square
control will be indirectly controlling with
pawns the more advanced d5 and e5

112
 frequently preventing opponent
breaks/counterplay there. As you can
easily see on the diagrammed position, e6-
e5 black central break is currently
impossible precisely because of the double
knight-pawn control over the e5 square; if
Nf3 were not present, e6-e5 would be
possible.
Despite its small value, this is an important
feature, but only in the mg, where its
influence spreads over a larger number of
pieces involved in the struggle.

Frequency: very frequent

Nf3 getting an additional bonus for White pawns on e4,d4, black pawns on
attacking e5 black pawn, Qf7 receiving the e5,d6; or white pawns on e4,d4, black
overbonus for assaulting white Nf3 and pawns on d5,e6
Rc4

Minor piece simultaneously attacking

with an own pawn one of the 4
centralmost squares: e4,e5,d4,d5

first version of the term

Nf3 attacking the e5 square,

simultaneously attacked by the own d4
pawn

Value: bonus, 7cps, only for the mg

Additional information: the bonus is due

for efficient control of the center,

113
 second version of the term a much much inferior central constellation
for the defending side
Value: penalty, -7cps, only for the mg, for
the side with the pair of aligned pawns

Additional information: no matter how

paradoxical it might seem at first glance to
penalise the side with more central pawns,
this is a very efficient way indeed for the
opposite side of challenging the enemy
prevalence in the center. In fact, this may
be the only wise way of doing so, as any
other configuration, involving a central
aligned pair for one side, and a central
configuration different from the above 2, is
very negative for the side lacking the pair.
For example, an aligned central pair on its
3rd rank, or just a single pawn on the
central d and e files, barring big other
relative advantages, would quite certainly another possible very inferior central
compromise the position of the defending constellation for the defending side
side. Something, of which most engines,
and also many humans, are unaware of in a I posted so many diagrams with just a
wide range of situations. couple of pawns present, as as many as
70% of all chess games might be decided
based just on central issues, and this is one
of them. Besides, as the pawn center is
built-up very early in the game, this makes
the feature even more important, as
whatever side gets an early
upperhand/manages to neutralise the
opponent advantage, will be crucial to the
whole game development.

114
 course, only favour the side with the semi-
central pawn
- when one semi-central pawn lands there,
this is a preparation for possible
establishment of a powerful central bind,
in the form of the c4 and e4 pawns, or f4
and d4 pawns. Such binds almost always
favour the binding side.
- as already declared, such moves happen
right out of the opening, so their
availability or lack will pretty much define
the course of the game

no matter how passive the black position

might look like, black does not have any
difficulties holding, precisely because the
central pressure is met the right way

Frequency: very frequent

The best move or semi-central pawns

controlling the center

Definition: c4 pawn, attacking the d5

square, that is free, or, alternatively, f4
pawn, attacking the e5 square, that is free yes, c4 is the best first move for white!
You might, of course, heartily laugh at this
Value: sufficient bonus, 20cps, just for the statement, but this is almost certainly the
mg truth. In any case, 1.c4 is better than 1.e4
and even more so than 1.d4. Black almost
Additional information: this is no doubt lacks in satisfactory replies.
one of the most important terms at all. It
arises right out of the opening, with the
very first moves, and will determine the
entire development of the game, so its
significance can hardly be overestimated.

The extremely-well deserved bonus is

dispensed for the following, rather
weighty, reasons:
- the semi-central pawn will control a
square where a central enemy pawn can
land, the exchange will see less central
pawn traded for an enemy central one,
both on their 4th ranks, so this can, of

115
challenging the center with 1...d5. if black counters with 1...e5 instead, white
This is certainly insufficient, as white has can continue with 2.Nc3, and after 2...Nf6
a very good reply in the form of the 3.e4!, we get to the above-posted position,
immediate c4-d5. almost never encountered in game play,
which tremendously favours white.
Yes, substantially. Whether you believe
me or not, is another matter, top engines
also do not see that move, but in another
20 years, both humans and engines will
understand 3.e4 is indeed the best possible
move.
As easily seen on the diagrammed
position, white has formed a central bind
in the form of the c4 and e4 pawns, the d5
square is additionally controlled by the
white knight on c3, and white has the
choice after g2-g3 and Bg2 to fianchetto
its light-square bishop on the king side,
also controlling d5 on an x-ray, so black
has almost no chance of pushing d7-d5 to
break in the center and free its
white has already won a pawn. Black will development. Thus, black will be totally
return it, of course, but will stay behind in pressed for space, the d4 outpost is quite
development and, most importantly, as an insufficient compensation in and of
easily seen, white remains with a more itself, and white can very successfully
valuable central d2 pawn, that will soon go continue with f2-f4 kingside storm after a
to d4, vs a less valuable semi-central c7 while, increasing the pressure.
pawn for black. That certainly makes a big
distinction.

116
you might doubt 1.c4 is the best first move countering with 1...e5 is insufficient.
for white, but the Sicilian, involving White gets quite an advantage after f4-e5,
precisely this feature after 1.e4 c5, a semi- trading a less central pawn for an enemy
central pawn, c5, attacking the empty more central one, but some still employ
central d4 square, is more or less proven to this gambit.
be the best black reply on 1.e4, right?
This should certainly strike a bell.

choosing 1...d5 instead provides white

with full equality after, for example, 2.Nf3
1.f4 is not at all bad, too. Its only Nf6 3.d4 Bf5 4.e3 c5 5.c3, though top
downside in comparison to 1.c4 is the fact engines will still assess this position as
that the f pawn is part of the white king substantially favouring black
shelter, and losing that pawn so early into
the game without any clear-cut variations
warranting it is certainly not the best of
things.

117
 Frequency: very frequent

Central bind

Definition: 2 own pawns, on c4 and e4, or,

alternatively, on d4 and f4

white has full equality. The game is

closed, and the excellent black outpost
square on e4 is largely compensated by the
great white central bind upon the e5
square.

central bind with f4 and d4 pawns

Value: large enough bonus, 40cps, only

for the mg(this is above the also dispensed
bonus for distant neighbours, as distant
neighbours can not quite fully capture the
specific condition, being dependent on
other, non-central pawns too)

Additional information: this is an

extremely valuable feature, wielding a
significant influence on the whole game.
The explanation lies in the fact that almost
always such a pair of pawns in the mg will
in the Stonewall Attack, white can even bind the center to great effect, making very
get much better. One pet Stockfish line for difficult to impossible an opponent central
black runs as follows: 1.f4 d5 2.Nf3 Nf6 break. Without a break, of course, it is
3.d4 e6 4.e3 c5 5.c3 Bd6 6.Bd3 Nc6 7.Ne5 difficult to find counterplay. In this way,
Qc7 8.Nd2 b6 9.Qf3 Bb7 10.0-0 0-0 11.g4, binding the center in the aboveshown way
and white gets a substantial edge. The is one of the most efficient paths to getting
obvious threat is g5, followed by Qh5, an upperhand, and should be strived at
capturing on e5 is very dangerous and will whenever possible, the earlier the better.
create a mighty defended white pawn
there, while the e4 outpost square is very Almost any promising opening line
well defended by white pieces, in the form includes such a constellation, although
of Bd3, Nd2 and Qf3. many, even top players, and engines as a

118
whole, still fail to completely appreciate it. give substantial white edge, but the truth
For example, the Maroczy Bind in the is, the position is fully equal. White can
Sicilian is one of the best ways to counter place an excellent central outpost on the e5
the Sicilian, giving white large advantage, square, but that is more than compensated
the Stonewall Attack is an extremely for by the black bind of the d5 and f5
efficient white weapon, no matter it might pawns upon the e4 square. Even when
look as bit passive at first glance, and, yes, white plays Ne5, followed by f2-f3, the e3-
black gets full equality in the Dutch by e4 break is extremely difficult to
implementing the Stonewall System. achieve(Nf6 controls e4 too), but apart
from that, in view of the inflexible white
pawn structure in the center, black has
much better chances to start a promising
kingside attack by pushing g and h pawns.)

Frequency: frequent

Closed position considerations

Closed center

Definition: a closed center would be

defined by one of the following pawn
arrangements:
a typical Maroczy Bind structure; d6-d5 - white pawns on d4,e5, black pawns on
pawn break in the center is very difficult to d5,e6
achieve, and therefore white has - white pawns on e4,d5, black pawns on
substantial advantage e5,d6
- white pawns on c4,d3,e4, black pawns on
c5,d6,e5
- white pawns on d4,e3,f4, black pawns on
d5,e6,f5

a typical Dutch Stonewall

(many humans would prefer white in the
Dutch Stonewall, and all engines would

119
 a closed center feature

white space advantage with closed center

another closed center feature Value: bonus, 15cps, only for the mg

Value: as in similar positions with a Additional information: this is a very

closed center the importance of long-term salient mg feature indeed. If one of the
positional factors increases, while the sides manages to get such a structure,
importance of shorter-term dynamic ones receiving the bonus, that would mean a
definitely decreases, it makes very much very durable positional advantage, which
sense to scale down/consider lower at least might be converted much later into the
mg piece mobility game. There are 2 main reasons for that:
- one of the quoted pawns of the
Frequency: frequent disadvantaged side, the least advanced
one, is virtually backward and, as it will
constitute part of the own king shelter, that
Space advantage with closed center backwardness is felt much more seriously;
for example, the defending side should be
Definition: space advantage with closed very careful when moving that pawn, as
center should be considered in one of the the king shelter might be severely
following 2 scenarios: compromised, and, if it does not move it
- white pawns on d4,e5, black pawns on too soon, the pressure on the kingside with
d5,e6,f7, black king on either the f,g or h the deficient backward pawn might get too
file strong in the medium and longer term
- white pawns on e4,d5, black pawns on - as the center is closed, such weakness is
e5,d6,c7, black king on either the c,b or a felt even stronger, as there is no possibility
file for a counter-break in the center

The sooner one gets a similar

advantageous position in the opening, the
better. On many occasions entire games
might be decided on this single feature.

Frequency: frequent

120
Closed positions are an extremely - white pawns on e3,d4,c5, black pawns on
interesting feature of chess. It is namely e4,d5,c6,b7, black king on either the c,b or
those positions that are the least a file
investigated of all. Humans do tend to - white pawns on f3,e4,d5, black pawns on
understand such positions better or much f4,e5,d6,c7, black king on either the c,b or
better than engines, but, believe me or not, a file
even top humans play them suboptimally,
or very much suboptimally, at least what
concerns a wide range of different
patterns. I would say, if there is progress to
be achieved in chess in the future, a
surprisingly big portion of it lies in
appropriately handling such structures.
Closed positions do mean positions where
the solution is to be found only after
getting to a much higher depth than
otherwise. They are associated with a lot
of manoeuvering, gradual increase of the
pressure, until the advantage of one side
becomes obvious, but, if you know well
the patterns, the advantage will be obvious
to you much much earlier. It is precisely
the depth-feature that makes such positions
so difficult for humans and engines alike. one possible pointed chain

Of course, we can talk about closed

position features, leading to a win for the
stronger side, and closed position features,
involving increased drawing chances with
larger blocked pawn structures/fortresses.
Here we will focus on the first, and
definitely much more intriguing feature.

Pointed chains

Definition: pointed chains are an

extremely appealing positional feature,
frequently disregarded even by top
humans, not to mention top engines.

The following conditions would see the another possible pointed chain, even closer
presence of alternative pointed chains: to the enemy black king
- white pawns on c3,d4,e5, black pawns on
c4,d5,e6,f7, black king on either the f,g or
h file
- white pawns on d3,e4,f5, black pawns on
d4,e5,f6,g7, black king on either the f,g or
h file

121
 the stronger side, as the center is closed,
central pawn breaks to open the game are
very difficult or impossible to achieve,
even in the long term, and getting
counterplay on one of the wings is much
less effective, so this all means the
stronger side has much more time to
slowly regroup its pieces and start a
decisive attack
- the durability of the structure is
additionally highlighted by the fact, that
the large central chains are blocked, with
blocked features being much more
constant and difficult to change, especially
what concerns chains
- pawn storms for the side with the pointed
a third variation, this time looking towards chain are encouraged to great effect, as the
the queenside enemy king shelter is less flexible to
counter them because of the backward
Value: bonus, 50cps, only for the mg pawn, and also because of the slower,
manoeuvering-like nature of the game
Additional information: the well- - provided the side of the board opposite to
deserved bonus is dispensed for the where the pointed chain looks to is fully or
following reasons: even partially closed, this will only make
- the enemy pawn on the 2nd rank, part of the pointed chain considerably more
the enemy king shelter, is necessarily valuable, as counterplay on the opposite
backward to different extents(depending wing will be very difficult or even
on whether there are other enemy pawns altogether impossible to achieve
on the 2nd rank next to it), and this makes
the enemy king shelter much more
vulnerable and inflexible than otherwise(as
the advance of this pawn is restricted,
dependent on tactical factors, this in turn
means much lower flexibility of the
shelter, and lower flexibility would mean
much stronger attacking chances for the
opponent)

Note: the presence of the enemy backward

pawn on its 2nd rank is an obligatory
feature of all pointed chains, otherwise the
feature would simply not work; it is not
only the pointed chain itself, but the
combination of the pointed chain with the
enemy backward pawn that makes the
pointed chain so efficient well, maybe you will recognise here a
typical King's Indian Defence pawn
- the closed center, with the presence of structure(with the valuable black pointed
large blocked pawn chains, imparts chain; once white manages to play g2-g4,
durability to the positional advantage of the black structural advantage is nullified)

122
and this one could arise with the more another type of inchoative pointed chain,
central pointed chain variation; looking towards the king side
structurally, white is winning that

Frequency: frequent

Inchoative pointed chains of 2 pawns

Definition: white pawns on c3,d4, black

king on e,f,g or h file, or, white pawns on
d3,e4, black king on e,f,g or h file, or,
alternatively, looking towards the queen
side, white pawns on f3,e4, black king on
d,c,b or a file, or, white pawns on e3,d4,
black king on d,c,b or a file

a type of inchoative pointed chain, looking

towards the queen side

Value: small bonus, 7cps, just for the mg

Additional information: the very-well

deserved bonus is given for the obvious
fact that such constellations start building
a pointed chain towards the enemy king,
and pointed chains are always a valuable
asset.

The bonus is only mg, as pointed chains

one type of inchoative pointed chain are valid only in this stage of the game.
looking towards the king side

123
 Larger inchoative pointed chains building a pointed chain towards the
enemy king. In distinction to inchoative
Definition: white pawns on c2,d3,e4, pointed chains of just 2 pawns, here things
black king on e,f,g or h file, or, are indeed a bit more advanced, so the
alternatively, looking towards the queen value is larger.
side, white pawns on f2,e3,d4, black king
on d,c,b or a file This concept can be very useful in the mg,
both for engines and humans alike. It is not
infrequent, that both entities will miss out
on good opportunities to play an opening
along the lines of creating a bigger pointed
chain looking towards the enemy king.
Pointed chains are always a significant
plus, and one of the mightiest positional
elements in chess in trying to gain
substantial advantage.

larger inchoative pointed chain, looking

towards the king side

many would think white has quite some

advantage, because of its powerful center,
as well as the better development. The
truth is otherwise, though. If any side, only
black could have advantage above, and the
reason is simple: black has already started
building a pointed chain towards the
enemy king with the availability of the
inchoative larger pointed chain in the form
of the c7,d6 and e5 pawns, that could be
larger inchoative pointed chain, looking continued with f7-f5, and further f5-f4,
towards the queen side slowly increasing pressure. Of course,
creating the longer chain closer to the
Value: bonus, 11cps, just for the mg enemy king would have been impossible,
if the whole process had already not been
Additional information: the bonus is prepared by the existing embryonic chain.
obviously due for initiating the process of

124
Alternatively, if black wants to stop in
some way the potential dangerous c4-c5
white counter-break on the queen side, it
can first play c7-c5, blocking c4, and only
then continue with the above-mentioned
plan on the king side. A smaller, and still
effective, inchoative pointed chain in the
form of the d6 and e5 pawns is still there,
so f7-f5-f4 is not a problem at all.

Pointed chains are indeed a very powerful

attacking tool, so implementing them
should never be neglected.

Frequency: frequent

alternative variation of the feature, looking

Central chain knight blockade towards the king side

Definition: white pawns on c3,e5, white

knight on d4, black pawns on c4,d5,e6, or,
white pawns on d3,f5, white knight on e4,
black pawns on d4,e5,f6, or, towards the
queen side, white pawns on f3,d5, white
knight on e4, black pawns on f4,e5,d6, or,
white pawns on e3,c5, white knight on d4,
black pawns on e4,d5,c6

one more variation, this time looking

towards the queen side

Value: sufficient bonus, 25cps in the mg,

10cps in the eg, for the side with the
knight

Additional information: the bonus for the

knight side is very well deserved because:
one variation of the feature, looking - the knight is defended by a pawn
towards the king side - the knight attacks an enemy pawn
- the knight blockades an enemy pawn in
the center, immobilising a valuable
opponent asset

125
- most importantly, with this condition, the Frequency: infrequent
game frequently will assume a more
closed character, and in case the side with
the knight is the attacking side, utilising Fully closed side with space advantage
the assets of the position, the well-placed on the other side of the board
attacking knight and especially the more
advanced friendly pawn, part of the Definition: valid under the following
structure, this will give it more time under conditions:
the cover of the blocked central structure - a,b,c,d files all closed with pairs of
to regroup and organise a successful pawn blocked or symmetrical twice backward
storm and piece attack on the side of the pawns(a symmetrical twice backward
board, where the more advanced friendly pawn would be one own and one enemy
pawn is pawn that are both twice backward, and
placed on the same file), white advanced
pawn on e5
- a,b,c,d,e files all closed with pairs of
blocked or symmetrical twice backward
pawns, white advanced pawn on f5
- e,f,g,h files all closed with pairs of
blocked or symmetrical twice backward
pawns, white advanced pawn on d5
- d,e,f,g,h files all closed with pairs of
blocked or symmetrical twice backward
pawns, white advanced pawn on c5

white has a winning position, although

some engines and probably many humans
might not be quite able to immediately
apprehend that.
Making use of the fact, that the position
bears a closed character, with c,d and e
files in the center totally blocked, and the
beneficial condition of the advanced
friendly pawn on e5, part of the structure,
white can start a forceful attack on the
king side, pushing g2-g4, h2-h4, then g4-
g5 or h4-h5, depending on circumstances, one possible variation, with all pawns
and then bringing both rooks to the king blocked(e5 is not necessarily a passer)
side, with a crushing attack.
In the meantime, black can do almost
nothing, as the center is blocked, no
possible pawn breaks or efficient piece
counterplay there, and counterplay on the
distant queen side is usually much less
satisfactory.

126
another possible variation, this time c3/c6 and one more, with the advanced pawn on
pawns are twice backward the queen side and both kings castled
opposite

Value: sufficiently large bonus, 50cps,

only for the mg

Additional information: the bonus is

dispensed for the simple, but extremely
efficient reason, that while the advanced
pawn on the 5th rank gives the side with
the pawn attacking advantage on that side
of the board, the fully closed feature of the
opposite side would make attaining
counterplay by the opponent there
extremely difficult or impossible. This
means the side with the advanced pawn
has all the time in the world to gradually
prepare and strengthen a mighty attack
and another one, with an f5 pawn against the enemy king, with both
storming pawns and pieces taking an
active part. Under usual conditions,
convenient regrouping would be difficult
to achieve, but not under these particular
conditions.

127
 b3, e3 and h3 squares are weak spots

Value: penalty, -10cps, just for the mg

Additional information: the penalty is

due for the fact, that such spots provide
easy penetration for the enemy pieces. The
pawn on the 2nd rank condition is
necessary, as this has a twofold function,
emphasising the weakness:
- further cramping the position for the side
with the weak spot, as otherwise the
square could be part of an open file, or at
least an own pawn on this file would be
too advanced to be backward
- ensuring that an own heavy piece along
well, white has excellent winning chances the file where the weak spot is, a rook or
with this pawn structure, considerably queen, would not be able to defend the
better than if the queenside was not locked weak spot, which might make it somewhat
with pairs of blocked and twice backward less prominent
pawns
Minor enemy pieces on a weak spot are
Frequency: infrequent naturally advanced outposts and only
further emphasise the weakness, as in this
way the pawn on the 2nd rank is immobile
Weak spots and due to stay there for quite some while.

Weak spots(also known as holes) are an

important square control feature.

Definition: a square on the 3rd rank, not

attacked by an own pawn, with another
own pawn placed on the same file on the
2nd rank

the black knight on the e3 weak spot and

the black bishop on the b3 weak spot
immobilise the enemy pawns on their 2nd
rank, highlighting the weakness

128
Weak spots, even if the square is not Symmetrical aligned pawns
currently occupied by an enemy piece, are
to be avoided, whenever possible. Definition: 2 own pawns on the same rank
on adjacent files, with another 2 enemy
Frequency: frequent pawns 2 ranks in front and the same files,
provided that the own pawns are on ranks
2 or 3
Own minor pieces controlling a weak
spot

symmetrical aligned pawns on the 2nd

rank
the white knight on d2 controls the weak
spot on b3, so that the black bishop on e6
can not penetrate there; the white bishop
on f2 controls the e3 weak spot, making
penetration by the black knight on f5 there
more difficult

Value: small bonus, different for the

bishop and knight, just for the mg:
- 5cps for the bishop
- 3cps for the knight

Additional information: the bonus is of

course due for the attempt at neutralising
possible enemy piece penetration on the
weak spot. A weak spot defended by an
own minor is less of a weak spot.
symmetrical aligned pawns on the 3rd rank
Frequency: frequent
Value: small bonus, distinguishing
between ranks

rank 2: 8cps in the mg, 2cps in the eg

rank 3: 12cps in the mg, 3cps in the eg

129
Additional information: the bonus is due
for the uncanny ability of the pawns to
close the game, whenever necessary. Thus,
they are a very valuable defensive asset.
As easily seen on above diagrams, if the
opponent side pushes one of its more
advanced pawns, trying to attack and open
the game, the defending side will have the
good choice of not capturing, but blocking
the other enemy pawn instead, with full
closure of both files. For example, on the
first diagram, if c4-c3 is played, white can
answer with b2-b3, fully closing both b
and c files, while, on the second diagram,
g5-g4 could be answered by h3-h4, and
h5-h4 by g3-g4, with similar closure.
in the center, symmetrical aligned pawns
are very helpful, too. d4-d5 break seems
like a very strong move, and indeed,
opening the game might have disastrous
consequences for black, bearing in mind
its considerable development lag. The
valuable asset of the central symmetrical
aligned d6 and e6 pawns, however, allows
black to effectively close the game in the
center, by answering d4-d5 with e6-e5. In
this way, the considerable development
advantage of white is annulled, at least
temporarily.
Central symmetrical aligned pawns have,
of course, large influence on the game as a
whole.

black has strong attack on the queen side Symmetrical aligned pawns are especially
and, in case it manages to open some files useful, when they are on the side where the
for attack there, it might get quite of an opponent has storming pawns. This can
advantage. Unfortunately, because of the prevent otherwise very unpleasant
peculiar pawn configuration of the b3 and storming pawns breaks with opening the
c3 symmetrical aligned pawns, opening position, breaking up the king shelter and
the game there is simply impossible. c5-c4 exposing the king.
is met by b3-b4, while b5-b4 by c3-c4,
closing both files.

130
black has substantial positional advantage black has a large material and positional
and is attacking on the king side. The h4 advantage in the eg, and would very easily
and g4 advanced storming pawns are win, were not it for the unfortunate
particularly menacing. If black manages to circumstance of the presence of the pair of
open the position on the king side, even a white symmetrical aligned a2 and b2
single file, white is doomed, and that in pawns, coupled with the fact that all
rather quick fashion. Unfortunately for the remaining board files are closed with pairs
attacker, the g2 and h2 symmetrical of blocked pawns. In the current situation,
aligned pawns, part of the white king this simply ends with a fortress position
shelter, provide an extremely useful and a draw, as a4-a3 is answered by b2-b3,
blocking possibility. Any attempt by black while b4-b3 by a2-a3, closing all files.
to open the game there will be futile, as
h4-h3 is answered by g2-g3, while g4-g3 Frequency: infrequent
by h2-h3. In order to win, black will have
to go the long way, preparing a break on
the queen side, or resort to mighty tactical
tricks. Pawn span

Symmetrical aligned pawns have one more Definition: the distance in files between a
valuable application, that of guaranteeing side's leftmost and rightmost pawn
full closure of the game and draw, in case
they are placed on the last 2 remaining
files that are still not closed by pairs of
blocked pawns.

131
1 file distance between black's leftmost, well, white is winning that, only because
d5, and rightmost, f5, pawn, 4 files of the bigger span of its pawns. While the
distance between white's leftmost, b3, and white king will be able to hold both of
rightmost, g3, pawn black's passers, his black counterpart will
not be able to do that with the 2 white
Value: bonus, 5cps in the mg, 10cps in the ones, far away from one another.
eg, for any file in between the two pawns The white pawn span requires from black
additional resources for defence, that black
Additional information: the bonus is due simply does not have.
for the obvious reason that a bigger pawn
span will usually denote the existence of a
passed pawn, or at least a candidate passed
pawn, for that side, and having such strong
pawns with bigger distance between them
will necessarily mean the opponent will
have to allocate more resources for the
defence against this strong pawn, which in
turn will ensure the attacker will be able to
concentrate more strength on the opposite
section of the board, gaining positional
advantages.

The extreme use of pawn span is easily

seen in simple pawn endgames, where a
bigger span almost certainly will lead to a
win.
adding a piece or two will still retain the
advantage for the side with the larger span,
but the edge will be much smaller and
dependent on concrete tactical factors

132
 Space advantage on both sides of the
board

Definition: having at least one pawn on

the 5th, 6th or 7th rank on the queen side
of the board, and, at least one other pawn
on the 5th, 6th or 7th ranks on the
opposite, king side of the board, provided
the distance between them is at least 3 files

Value: bonus, 20cps in the mg, 10cps in

the eg, for the side, gaining space this way

Additional information: the bonus is due,

because:
- having advanced pawns, either in the mg
candidate passed, instead of passed pawns, or eg, is pressuring the opponent and,
like a4 and h4 above, ensuring a bigger when such pawns are present on both
span, will also give the side with the larger board sections, the need to neutralise the
span good winning chances, or at least a pressure is even more urgent and will
substantial advantage require more resources. Threats on a single
focal point are usually easier to repel, in
order to do that on different board
sections, one needs more available
strength.
- space gained by pawns on opposite sides
is conducive to unlocking difficult to win
positions, with a possible break at a
propicious point in time, as breaking
attempts will be available on more
locations

in the mg, pawn span is very much

relevant, too. If white manages to install a
passed pawn on a5, after a5 ba5 ba5,
bringing the pawn span difference to 2
files, it will certainly have good winning
chances, in spite of the equal material.

The eg value is twice higher than the mg

one, as in the eg pawns defining the span
will more frequently be dangerous passers.
having space advantage on both sides of
Frequency: frequent the board, in the form of the advanced h5

133
and c5 pawns, with more than 3 files Chapter IV
distance between them, severely pressures
black, who has to defend more
weaknesses, further apart. That certainly is Outposts
a resource-drainer, and white has a number
of good continuations.
At some point, if not something quicker, a
break, either on b5, on the queen side, or Outposts are one of the most significant
f5 or g5(after g2-g4 is played) on the king features in chess, placing second
side, will decide the outcome. immediately after pawns. The reason is
obvious: minor pieces, to which outposts
primarily relate, are the second most
numerous piece on the board after pawns,
and their relatively small material value
makes them especially good in gaining
space advantage, with space advantage
always playing a major role.

Definition: an outpost within the current

framework is a minor piece(knight or
bishop) on ranks 3 through 6 with no
enemy pawns present on more advanced
ranks than the minor piece itself on
adjacent files

Note: however, this is just the general, and

very restricted definition. Apart from
in the eg, having space advantage on both minor piece outposts, there are rook
sides of the board will often take the form outposts too, a wide range of semi-
of advanced passers and potential passers. outposted features(involving the presence
The g5/h5 and a6 pawns on the king and of an enemy pawn on more advanced
queen sides respectively severely drain ranks, that would however be in some
black's resources. Defence and respect immobilised or made unable to
communication between distant board realistically threaten the outpost in another
sections will be difficult. way), and also some outposts on the 7th
rank.
Note: the requirement the pawns should be
separated by at least 3 files is necessary, as
otherwise defending weaknesses close to
each other is much easier

Frequency: frequent

134
 No-pawn-defended outposts

Definition: a minor outpost that is not

defended by an own pawn

white knight outpost on the central d5

square, black bishop outpost on the g3
square

Additional information: as said, outposts

are very important. They receive a well- Nc6 is such an outpost; Bf3 is another one
deserved bonus for a variety of reasons:
- stable, unattackable by enemy pawns, Value: bonus, valid in terms of psqt,
and in chess stability is frequently making a distinction between knight and
associated with surplus value, simply bishop outposts, as they all have their
because a non-stable feature might easily specifics
disappear altogether
- in most cases, when on ranks equal or 8 0 0 0 0 0 0 0 0
higher than 4th, also advanced, 7 0 0 0 0 0 0 0 0
representing space advantage features, 6 50 80 100 120 120 100 80 50
restricting enemy pieces' activity 5 30 50 70 90 90 70 50 30
- in a wide range of specific situations, 4 20 30 40 50 50 40 30 20
outposts also perform very particular other 3 10 15 20 25 25 20 15 10
valuable functions, like blocking the 2 0 0 0 0 0 0 0 0
position for the purposes of attack and 1 0 0 0 0 0 0 0 0
a b c d e f g h
defence, representing durable king-
attacking features, stopping enemy rooks
from taking open files, supporting the no-pawn defended knight outpost psqt(mg)
advance of own passers, etc.
8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
Frequency: very frequent
6 22 33 42 55 55 42 33 22
5 10 20 27 38 38 27 20 10
Further, we will examine the different 7 10 13 17 17 13 10 7
4
outpost features. 3 4 6 7 9 9 7 6 4
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

no-pawn-defended knight outpost psqt(eg)

135
 8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 50 85 90 130 130 90 85 50
5 30 50 60 80 80 60 50 30
4 18 25 35 43 43 35 25 18
3 10 15 20 25 25 20 15 10
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

no-pawn-defended
bishop outpost psqt(mg)

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 22 36 40 55 55 40 36 22
5 10 20 23 33 33 23 20 10
4 6 8 12 15 15 12 8 6
single-pawn-defended
3 4 6 7 9 9 7 6 4 knight outpost on e5
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 Value: bonus, valid in terms of psqt, while
a b c d e f g h making distinction between knight and
bishop outposts
no-pawn-defended bishop outpost psqt(eg)
8 0 0 0 0 0 0 0 0
Additional information: no-pawn- 7 0 0 0 0 0 0 0 0
defended outposts get all of the advantages 6 65 100 130 150 150 130 100 65
of general outposts, with the additional 5 38 70 85 110 110 85 70 38
downside that they represent less stable 4 27 38 53 65 65 53 38 27
features than otherwise, as any enemy non- 3 12 19 28 35 35 28 19 12
2 0 0 0 0 0 0 0 0
pawn piece could easily threaten them,
1 0 0 0 0 0 0 0 0
forcing retreat, or even destroying them.
a b c d e f g h
Of course, if any friendly piece apart from
pawn does defend them, that only
single-pawn-defended
enhances their value, as they become
knight outpost psqt(mg)
relatively more stable, though non-pawn
defence tends to be a bit flimsy at times. 8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
Frequency: frequent 6 28 45 60 70 70 60 45 28
5 15 28 35 55 55 35 28 15
4 9 14 18 25 25 18 14 9
Single-pawn-defended outposts 3 5 7 9 12 12 9 7 5
2 0 0 0 0 0 0 0 0
Definition: a minor outpost that is 1 0 0 0 0 0 0 0 0
defended by a single own pawn a b c d e f g h

single-pawn-defended
knight outpost psqt(eg)

136
8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 65 100 115 170 170 115 100 65
5 38 70 80 90 90 80 70 38
4 23 38 48 65 65 48 38 23
3 12 19 28 35 35 28 19 12
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

single-pawn-defended
bishop outpost psqt(mg)

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 28 45 60 70 70 60 45 28
5 15 28 35 50 50 35 28 15
4 8 14 18 25 25 18 14 8
twice-defended bishop outpost on d6
3 5 7 9 12 12 9 7 5
2 0 0 0 0 0 0 0 0 Value: bonus, valid in terms of psqt,
1 0 0 0 0 0 0 0 0 distinguishing between knight and bishop
a b c d e f g h features

single-pawn-defended 8 0 0 0 0 0 0 0 0
bishop outpost psqt(eg) 7 0 0 0 0 0 0 0 0
6 65 100 150 180 180 150 100 65
Additional information: single-pawn- 5 38 70 100 120 120 100 70 38
defended outposts inherit all advantages of 4 27 38 53 65 65 53 38 27
general outposts, and get reasonably 3 12 19 28 35 35 28 19 12
2 0 0 0 0 0 0 0 0
higher bonus than no-pawn-defended
1 0 0 0 0 0 0 0 0
outposts for the simple reason that they are
a b c d e f g h
stronger and do represent substantially
more durable feature
twice-defended knight outpost psqt(mg)
Frequency: frequent 8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 28 45 60 70 70 60 45 28
Twice-defended outposts 5 15 28 35 55 55 35 28 15
4 9 14 18 25 25 18 14 9
Definition: a minor outpost that is 3 5 7 9 12 12 9 7 5
defended by 2 own pawns 2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

twice-defended knight outpost psqt(eg)

137
8 0 0 0 0 0 0 0 0 install a major defended and centralised
7 0 0 0 0 0 0 0 0 pawn, with other squares giving almost no
6 65 100 130 220 220 130 100 65 added value. Still, for this particular
5 38 70 85 110 110 85 70 38 number of squares, the distinction is pretty
4 27 38 53 65 65 53 38 27 huge.
3 12 19 28 35 35 28 19 12
2 0 0 0 0 0 0 0 0 Frequency: frequent
1 0 0 0 0 0 0 0 0
a b c d e f g h
Twice-defended knight outposts on the
twice-defended bishop outpost psqt(mg) 5th rank with no enemy pawns on the
same file as the outpost on more
8 0 0 0 0 0 0 0 0
advanced ranks
7 0 0 0 0 0 0 0 0
6 28 45 60 70 70 60 45 28
5 15 28 35 55 55 35 28 15
4 9 14 18 25 25 18 14 9
3 5 7 9 12 12 9 7 5
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

twice-defended bishop outpost psqt(eg)

Additional information: twice-defended

outposts inherit all the advantages of
general outposts, but are due higher value
than even single-pawn defended outposts,
because:
- they are immeasurably
stronger(completely impossible to destroy
them without receiving severe positional c5 is such a knight outpost above
penalties)
- because being stronger, they are also Small bonus, 10cps, only for the mg, is
much more durable, so their influence on dispensed for the fact that any enemy piece
the game will be felt for a much more capture of such a minor will lead to the
prolonged period of time creation of a strong, defended and
- any possible capture of such an outpost advanced, friendly passer on the square
by an enemy piece will result in the previously occupied by the knight(see
building-up of an advanced own defended diagrammed position).
pawn on the square where the outpost Possible squares for such a knight posting
previously stood, in some cases even are b5 through g5; the reason that only
passer(as the outpost is defended twice, the knights get such a bonus is that, while all
new friendly pawn on its place will also be similar knights are central, a bishop placed
defended, see the diagrammed position) on b5/g5, and even c5/f5 would definitely
seem awkward and a bit misplaced(no
Note: twice-defended outposts will differ possible to go back, both own pawns
from single-pawn-defended outposts in defending it will prevent that).
their psqt values for just a number of In the endgame, such a feature is largely
central squares on the 5th and 6th ranks, irrelevant, as space advantage plays a
where a capture by an enemy piece would

138
significantly smaller role there and such
knights could easily be tolerated.

Permanent minor piece outposts

Definition: minor piece outpost, with no

enemy minor pieces able to attack them

Note: that will basically mean the lack of a

knight, as knights are generally able to
attack all board squares, independent of
their colour, or, the lack of a bishop the
colour of the square the minor piece is
outposted on

another permanent minor piece outpost,

the knight on d5. As easily seen, no enemy
minor pieces present, able to attack the d5
square, aiming at destroying the strong
knight.
If any side, and despite being a pawn and
the exchange down, only white could have
advantage above.

the bishop on f5 is a permanent minor

piece outpost, no enemy minor pieces on
the board, that would be able to attack it

and one more, the bishop on e5

Value: sufficiently large bonus, over the

already dispensed one for a general
outpost, in terms of rank

5th or 6th rank: 50cps for the mg, 15cps

for the eg
4th rank: 15cps for the mg, 5cps for the eg

139
Additional information: the very-well
deserved bonus is obviously due for the
following weighty reasons:
- as such an outpost will be unattackable
by enemy minors, that will mean it will be
undestroyable
- being undestroyable in turn means
durability, and durability is always an
asset, especially with strong features
- on occasion, due to the closed character
of the position, such an outpost will be
unattackable even by enemy rooks, so this
will further boost its value

what a powerful outpost, the bishop on e6!

Advanced, twice defended, and
unattackable by enemy minors. White
certainly has a winning advantage. About
the best black could do is to sacrifice an
exchange on e6, but that will hardly help
too.

the strongly-defended permanent bishop

outpost on d4, plus a bit more favourable
imbalance, fully compensate the material
deficit. White has clear advantage.

eternal knight on e5. The knight is

sheltered by an enemy pawn, with the
position being closed, so no enemy rook
can ever attack it, trying to destroy it.
This only highlights white's advantage,
and white will certainly win after the h3-
h4-h5 break.

140
 Frequency: frequent

Outposts blocking enemy pawns

Definition: minor outposts on their 4th,

5th or 6th ranks, blocking enemy pawns

even in the eg, and even on the 4th rank,

such outposts are undoubtedly very useful.
If any side, only white can win the position
above.

the knight on d5 is such an outpost on the

5th rank. It blocks the enemy d6 pawn.

of course, it is even better to have 2 of

those. The all-powerful knight on d6 and
bishop on e5, unchallenged by enemy
pieces, certainly more than compensate for
the big material deficit.

The mg value is significantly larger, as

outposts in general are much more relevant one more similar outpost, this time on the
in the mg. 4th rank, the knight on c4 blocks the
enemy c5 pawn
Overall, this is one feature, whose
importance can hardly be overestimated.

141
and one on the 6th rank. The knight on b6 the knight on b6 immobilises the black b7
blocks the enemy b7 pawn. pawn, and this has a cramping effect upon
the whole black position
Value: bonus, 10cps, both for the mg and
eg

Additional information: the very-well

deserved bonus is due for the following
reasons:
- the enemy pawn is immobilised, which is
especially of an asset, when it is closer to
its home rank
- frequently, primarily in the mg, but also
in the eg, this has a cramping effect upon
the enemy pieces
- the outposted minor is unattackable by
enemy heavy pieces along the file where it
sits, as the enemy pawn shelters it
- when blocking an enemy pawn, part of
the king shelter, the shelter as a whole
becomes less flexible the knight on c5 is unattackable by the
black rook on c8. Breathing space for the
black pieces is also quite limited.

142
 the outpost on more advanced ranks, not
attacked by any other own pawn or piece,
and attacked by at least one enemy piece

Value: sufficient penalty, -30cps in the

mg, -10cps in the eg

Additional information: the penalty is

because of the largely useless nature of
such outposts. As the outpost will be
placed far from the enemy king, it will not
be able to attack it. What is even worse,
because all squares on more advanced
ranks the outpost can access are controlled
by enemy pieces, the outpost will not be
able to transfer from them to different
when blocking a shelter pawn, g6 above, sections of the board, including the center
such outpost additionally makes the shelter or king side. So, the most it can actually
less flexible do, is stay where it is, doing nothing, or
possibly go back on less advanced ranks in
the own camp, but that is something no
outpost would like to do. In this way, the
outpost is completely disfunctional.

even on the 4th rank, and even in the eg,

such immobilisation definitely has its
advantages

Frequency: very frequent the knight on b4 is such an outpost.

All squares on more advanced ranks, a2,c2
and d3, are controlled by white pieces,
even if only the bishop on b1, and not
Useless outposts supported by any own piece. So, the most
the outpost could do is stay where it is, and
Definition: minor piece outpost on the 5th white has winning advantage.
or 6th ranks on files a or b, or h or g, on
the side of the board, opposite to where the Frequency: infrequent
enemy king is, with all squares attacked by

143
 Unretreatable knight outposts

Definition: knight outpost on its 5th or 6th

rank, on files a,h,b or g, with all its
mobility squares on less advanced ranks
controlled by enemy pawns

one more example, this time with a knight

on its 5th rank.
All the knight's mobility squares on less
advanced ranks, a6,c6 and d5, are under
the control of enemy pawns, while its
mobility squares on more advanced ranks,
a2,c2 and d3, are restricted by the white
the knight on a3 is an unretreatable knight bishop on b1.
outpost on the edge a file.
All the mobility squares of the knight on
less advanced ranks than the knight itself,
b5 and c4, are controlled by white pawns,
c4 and b3 respectively.

Value: penalty, -15cps, both for the mg

and eg

Additional information: the penalty is

given because of the obvious mobility
limitations of such outposts. Although
otherwise excellently placed, they can not
possibly retreat, as enemy pawns will
prevent that, while more advanced
mobility squares will usually be attacked
by enemy pieces, as is the case with the
white rook on b2 on the diagrammed this condition is very negative, also when
position, attacking the b1 and c2 squares, the outposted knight directly attacks
so their functioning is pretty much limited squares of the enemy king shelter.
to a very small section of the board, and Although one might think the black knight
sometimes, because of that, they are even on h3 is very strong, in actual fact it is
trappable. quite fragile, as it can not retreat, and after
the white rook moves from f1 and its place
is taken by the white bishop, the easily
trappable knight comes under attack and

144
perishes together with the pawn defending Value: small bonus, different for the
it. knight and bishop
- 15cps in the mg, 5cps in the eg for the
Frequency: infrequent knight
- 12cps in the mg, 4cps in the eg for the
bishop
Semi-outposts
Additional information: the bonus is
Definition: semi-outposts are outpost- given for the following reasons:
related features, a knight or bishop on - the own pawn in front of the minor piece
ranks 3 through 5, that are not pure prevents any possible attack by an enemy
outposts proper, in the sense that there are pawn(on the diagrammed position, c7-c5
enemy pawns on more advanced ranks on would be met by d5-c6, f7-f5 and h6-h5
one of the adjacent files, but those pawns thrusts also do not represent a danger to
do not represent immediate threat to the the bishop, as g4 pawn could capture both
outpost, because they are either unable to sides)
move forward as being blocked by - the minor pieces are also protected from
opponent pawns or pieces, or a possible file attacks of enemy heavy pieces, with
pawn push is thwarted by an opponent the pawn in front shielding them
pawn guarding the square in front of them
Frequency: frequent
Such features are extremely different and
wide-ranging. Below, we will briefly look
at the most salient ones. Minor piece with an own pawn
diagonally in front of it

Minor piece behind an own pawn Definition: a minor piece on the 3rd, 4th
or 5th ranks with an own pawn one rank
Definition: a minor piece on the 3rd, 4th upper on adjacent file
or 5th ranks with an own pawn placed
immediately in front of it on the same file
one rank above

Nc4 and Bf5 represent such semi-outposts

Nd4 behind d5 pawn and Value: small bonus, different for the
Bg3 behind g4 pawn knight and bishop

145
- 10cps in the mg, 3cps in the eg for the Value: small bonus, different for the
knight knight and bishop
- 8cps in the mg, 2cps in the eg for the - 10cps in the mg, 3cps in the eg for the
bishop knight
- 8cps in the mg, 2cps in the eg for the
Additional information: bonus is bishop
dispensed as:
- an enemy pawn on the adjacent file Additional information: the bonus is
where the friendly pawn is could not given due to the following considerations:
possibly attack the minor, as the friendly - the friendly pawn on the same rank
pawn blocks its further push(see the across a file prevents an enemy pawn push
diagrammed position; d6-d5 push to to threaten the minor piece, as the enemy
threaten the knight is currently impossible pawn could be captured(see diagrammed
because d5 pawn blocks d6, g7-g6 push position; on c6-c5 push, there is a d4-c5
threat to attack the white bishop on f5 is capture, while on f7-f6 push, a g5-f6
thwarted too, as g6 pawn blocks g7) capture)
- even if enemy pawns are not present, the - if the minor is a knight, it will control on
knight will support the own pawn push, occasion the square in front of the friendly
while the bishop will defend the own pawn, rendering a pawn push easier, while,
pawn, which is particularly important, if in the case of a bishop, the bishop will
the own pawns are passers additionally control the square for the
enemy pawn push(on the diagrammed
Frequency: frequent position, even though f7 black pawn is
aligned/connected, and g7 supports the
possible f7-f6 push, this push is thwarted,
Minor piece with an own pawn on the because of the double Be5-pawn g5
same rank across a file control of the f6 square)

Definition: a minor piece on the 3rd, 4th Frequency: frequent

or 5th ranks with an own pawn on the
same rank 2 files apart
Minor piece on the 4th rank with an
enemy pawn on its second rank on
adjacent file that is backward

Nb4 and Be5 are such semi-outposts above

146
 Ba4 and Ne4 are similar minors above Value: small bonus, equal for the knight
(b7 and f7 are backward pawns) and bishop, 10cps for the mg, 3cps for the
eg
Value: small bonus, different for the
knight and bishop Additional information: the bonus is
- 8cps in the mg, 2cps in the eg for the given for the impossibility of an enemy
knight pawn on adjacent file to attack the minor
- 6cps in the mg, 2cps in the eg for the piece. As the square for a potential enemy
bishop push is currently occupied by the other
opponent outposted minor, such a push is
Additional information: bonus is due unrealistic(see how on the diagrammed
because: position black c5-c4 push to threaten Bb3
- the enemy pawn on adjacent file could and g7-g5 push to attack Nf4 are out of the
not possibly attack the minor, as it is question, as white Nc4 and Bg5 outposts
backward, and any push could easily be take up the push squares).
captured by the opponent pawn making it
such(see b7 and f7 pawns on the Frequency: infrequent
diagrammed position; they are both
backward, b7-b5 thrust would be met by
c5-b6 capture, while f7-f5 thrust by g5-f6 Minor piece on the 4th rank with
one) another own minor piece outposted on
- in the case of a knight, it would the 6th rank on adjacent file
additionally control the square in front of
the backward pawn, making a sally even
more difficult

Frequency: infrequent

Minor piece with another own outposted

minor one rank in front on adjacent file

Bb4 and Nf4 are such semi-outposts

Value: small bonus, equal for the knight

and bishop, 8cps for the mg, 2cps for the
eg

Additional information: the bonus is

given for the impossibility of a potential
pawn push, threatening the minor, of an
Bb3 and Nf4 are similar semi-outposts existing enemy pawn on the adjacent file

147
where the other own outposted minor Minor outposts on the 7th rank
piece is. As you can see on the defended by a pawn
diagrammed position, Na6 outpost thwarts
the possible a7-a5 push with threat upon
the Bb4, while Bg6 effectively blocks the
black g7-g5 thrust, with a threat upon Nf4.

Frequency: infrequent

Knight on the 5th rank with enemy

knight on the 6th rank on adjacent file

Nc7 for white and Bb2 for black are such

outposts

Value: sufficiently large bonus over the

general psqt one, 30cps in the mg, 15cps in
the eg, both for the knight and bishop

Additional information: the bonus is

given for the following reasons:
- as in the case with other advanced
Nc5 is such a knight outposts, though less markedly, such
minor pieces do severely restrict the
Value: very small bonus, 5cps for the mg, activity of the enemy non-pawn pieces,
2cps for the eg primarily queen and rooks
- in distinction to a non-pawn-defended
Additional information: the bonus is minor outpost on the 7th rank, a pawn-
given for the fact that a possible enemy defended one is much more durable and
pawn push with threat upon the knight is difficult to evict, hence the bonus; non-
made more difficult by the presence of an pawn-defended minor outposts on the 7th
enemy knight in front of the enemy pawn, rank would have difficult task sticking to
thus blocking its march(see Nb6 blocking their place
own pawn on b7 and currently preventing - if such an outpost is captured by an
the b7-b6 push). Usually, the situation is enemy piece, its place is immediately
only short-term, though. taken by a very advanced passed pawn on
the 7th rank, a single square away from
promotion
- in case the defending pawn is a passer,
the minor outpost will support its further
advance to promotion(for example, on the
diagrammed position, after Nc7-e6, the
knight will control the d8 promotion

148
square, and Bb2 already controls black c1 important board squares, including an
promotion square) attack upon the black king shelter, and
possible enemy minor captures will
Frequency: frequent introduce a strong defended pawn on that
very same e5 square.

Twice defended knights Twice defended knights are extremely

relevant for one more reason, namely that
Definition: knight, on d5,e5,c5 or f5 they can appear quite early into the game,
squares, defended by 2 own pawns having influence upon a wide range of
openings, and thus the side that manages
Note: the knight should not be an outpost, to attain such a positional advantage first
as twice-defended minor outposts are will usually also gain an overall strategic
already scored within our evaluation advantage.
framework Missing this opportunity and going for an
alternative line instead, that would be
Value: bonus, 15cps, just for the mg clearly inferior, is missing a lot, so this is
certainly not a factor to be disregarded as a
Additional information: the very-well simple nicety.
deserved bonus is given for the following
reasons:
- unless attacked by an enemy pawn, the
knight is very stable and durable there, and
those are vital central and advanced
squares, from where the knight enjoys
sway over almost the entire board
- if the knight is exchanged for another
enemy minor piece, an extremely well
placed advanced defended pawn will
appear on the square the knight previously
held, again an indisputable advantage

a typical Dutch Stonewall construction.

Many humans would avoid the Dutch
Stonewall, for unknown reasons, and all
engines, even the very finest, will consider
above position as very favourable for
white(close to or more than half a pawn
advantage), but the truth is black is already
slightly better.
The main reason, apart from the excellent
central bind in the form of the d5 and f5
pawns, is the gorgeously placed twice
defended knight on e4, immediately
twice defended knight on e5. The knight is attacking the white king shelter. It is
very stable there, controlling almost all difficult to long tolerate such a knight,

149
changing it will quickly send a strong - 5cps in the mg, 2cps in the eg for a rook
defended black pawn on e4 instead of the outpost on the 5th rank
knight, which will further very negatively
influence the white king shelter, and trying Additional information: include this
to kick it with a pawn is also not easy and feature to spice up your engine evaluation,
takes some time(the white knight on f3 or to have a deeper understanding of
should evacuate the f3 square first). ongoings on the board. Bonus is given for
Besides, some captures are even tactically the impossibility of enemy pawns to attack
impossible, for example, Nc3-e4 loses a the rooks, which makes the feature
minor piece by force. somewhat more durable and, as an
Black threatens with a mighty assault after advanced feature, attacking
g7-g5, g5-g4, h7-h5, Rf8-f7-h7, etc., or, objects/squares in the enemy camp, it is
alternatively, placing the black rook on the valuable. Not very salient, though, as such
g file, then bringing the rest of the pieces outposts could still be attacked and
on the queen side to support the attack. neutralised by enemy minor pieces.

Frequency: frequent Frequency: frequent

Rook outposts Rook on the 6th rank, defended by

pawn
Definition: rook on the 4th or 5th ranks
with no enemy pawns on more advanced
ranks on adjacent files

Rc6 is such a rook

Value: bonus, 10cps in the mg, 5cps in the

white rook outpost on b5 on the 5th rank; eg
black rook outpost on e5 on the 4th rank
Additional information: the bonus is
Note: this is a bit pedantic, but might be of given because:
interest to truth-searchers - the rook is outposted there, stable and
more difficult to attack
Value: very small, - in case such a rook is captured, by an
- 3cps in the mg, 1cp in the eg for a rook enemy rook, or even by an enemy minor
outpost on the 4th rank piece with possible sacrifices, on its place

150
will immediately land a powerful passed Twice defended rook on the 6th rank
pawn(as easily seen on the diagrammed
position, Rc8-c6 is not the best move) Definition: rook on the 6th rank, defended
by 2 own pawns
Frequency: frequent

Rook on the 7th rank, defended by

pawn

Rd6 is such a rook

Value: bonus, 20cps in the mg, 10cps in

the eg

Rc7 is such a rook Additional information: the bonus is due

because:
Value: bonus, 15cps, both for the mg and - the rook is well-defended and stable there
eg - in case it is captured, either by another
rook, or even by an enemy minor piece
Additional information: the bonus is with possible sacrifices, its place will be
given for the following reasons: immediately taken by a very strong
- the rook is excellently placed there, defended passed pawn
durable and difficult to attack by enemy - if such rook lands on a square of the
pieces enemy king shelter, different sacrifices are
- in case it is captured, a very powerful possible, too, going as long as to sacrifice
friendly passed pawn, a single square away the rook for a mere enemy pawn
from promotion, will immediately take its
place
- in the eg, the defending pawn will
frequently be a passer, so the rook will
support the advance of the pawn forward,
while the pawn will help with the rook
penetration

Frequency: frequent

151
such rook frequently helps with the fight and if such rook lands on a square of the
for an open file. Above, as capturing on d6 enemy king shelter, flashy sacrifices,
is close to impossible, as this will involving big temporary material losses,
introduce there a powerful white protected are often seen, too.
passer, the black rook on d8 will have to Capturing the rook above leads to a quick
retreat, after which white penetrates with white mate after gf6 and Qh6.
an easy win.
Frequency: infrequent

Rook outposts blocking enemy pawns

Definition: outposted rook on the 5th or

6th ranks, blocking an enemy pawn

sacs are also possible. For example, on the

diagrammed position, Bb3 quickly loses
the game, after cb3, followed by Nc4.

the rook on g5 represents this condition. It

is outposted and blocks the enemy g6
pawn.

152
Value: small bonus, 4cps in the mg, 2cps Penetration points
in the eg
Definition: square on the 5th or 6th ranks,
Additional information: the bonus is due, that is empty, defended by an own pawn,
because with this condition enemy pawns and not attacked by an enemy pawn
are immobilised, depriving the opponent
of a valuable positional asset in the form Value: bonus, valid only for the mg,
of the ability to push pawns further. different for the 2 separate ranks:
- 6cps for the 5th rank
- 10cps for the 6th rank

Additional information: the bonus is due

for the possible penetration of all kinds of
own pieces upon this square, which is an
advanced one and important therefore well
into the enemy camp. The asset is just a
potentiality, as a piece might also not quite
get there sometimes, but very well
calculated one.
Advanced squares are always a welcome
haven, so it is just about natural that all
pieces strive to reach them. Those might
be future own outposted minors, but also
minor pieces on the 5th rank that would
not be outposts, as well as rook or queen.
the b7 pawn can not budge, is vulnerable, An own pawn securing the place ensures
and thus, white enjoys big advantage the square will be mostly safe, when a
piece lands there, and an enemy pawn not
attacking it is a precondition for
penetration. The condition the square
should be empty is necessary because
otherwise the feature could also
encompass minor outposts and other
pieces already having penetrated, which
are separately scored.

The term is only mg, as in the mg there is

an abundance of different pieces able to do
the trip to such a square, and besides in the
eg the relevance of such squares would
almost fully vanish, as space advantage, an
inherent element of penetration points, is
much less significant in that stage of the
game. A clear testimony to this is the
in the eg, such rooks are frequently a big diminishing value of minor outposts, as
plus, even with a material deficit well as the much smaller importance of
enemy king attack, where advanced well-
Frequency: frequent placed heavy pieces close to the king will
frequently have major role to play.

153
the b5 square is a penetration point for b6 is a penetration point on the 6th rank
white on the 5th rank. It is attacked by the for white. After some manoeuvering, the
a4 white pawn, empty, and not attacked by d3 white knight can go there, via b2 and
a black pawn. Currently, the e2 bishop can a4, for example, the white bishop on c1
go there, but, in just 2 more tempi, after can join it, in a possible Bc1-a3-c5-b6 trip,
Nb1-a3-b5, the white knight on b1 can and later in the game, other own pieces can
also take it and, in the more distant future, follow too.
with some simplifications, it is a possible h3 is a penetration point on the relative 6th
target for the white queen and, under rank for black. Currently, it does not look
specific conditions, even a white rook. very accessible, but, after some
In this way, even if it is not currently preparation, for example, h7-h5, Nf6-h7-
occupied, it is an extremely useful g5, the black knight can start threatening
positional asset, allowing all pieces to penetrating there, and, later in the game,
change places, take it, and start pressuring other black pieces would be able to join.
the opponent. One peculiarity of this square is that it is
e5 is another penetration point for white on also part of the white king shelter, so this
the 5th rank, and e4 a penetration point for makes it an even more valuable point of
black on the same relative 5th rank. Both penetration.
squares are attacked by own pawns and not e5 is a another penetration point for white
under immediate attack of enemy pawns. on the 5th rank, and e4 for black.
They are a bit less safe than the b5 square,
as enemy pawns potentially can still attack Frequency: very frequent
them, but still a very good spring-board for
own pieces trying to penetrate the enemy
half of the board.
b4 and c4 squares, on the other hand, are
not penetration points for black, as,
although defended by black pawns, they
remain under attack of the c3 and b3 white
pawns respectively.

154
 Chapter V Further, we will look at the most basic
imbalances rules.

Imbalances Pair of bishops

Imbalances are one of the most interesting

features in chess. Usually, they are so
complicated and mostly not deeply
researched, that only very few top engines
will be able to play them only half-
decently, because of lack of understanding,
and almost no top human player will be
able to reasonably implement their core
values on the board, both because of an
inherent lack of understanding, and due to
the fact that humans are more error-prone
in such constellations in view of the fast-
changing nature of the game.

The scientific approach to imbalances will white has excellent winning chances,
require building of a complete table of all although one might think almost
possible piece imbalances with their everything is equal: 2 pawns each side, 2
relevant values, but, as such a table will minor pieces each side; yet, the pair of
hold up to some hundred thousands bishops make big difference
possible combinations, this is simply
impractical. Therefore, the best that could Value: bonus, 30cps in the mg, 50cps in
currently be done is to rely on a small the eg
number of largely valid rules, that would
not be perfect, but would still give a fairly Additional information: the bonus is
good overview of board occurences. given due to the following considerations:
- the pair of bishops control in tandem all
If we had to briefly define what squares on the board easily, light and dark
imbalances are all about, imbalances are alternatingly, which a pair of knight and
the overvalue of pieces above their plain bishop simply can not do; the knight will
values that only the combination of 2 or access squares of colour different to the
more of them would be able to assign to colour of the own bishop, but only
them. In that sense, in order to have an randomly and much harder
imbalance situation, you would need at - the pair of bishops is much faster in
least 2 pieces for at least one of the sides, moving across the board than a pair of
and, in order to meaningfully calculate knight and bishop, for example
them, you would need that one of the sides - it is possible to exchange one of the
has at least one piece unmatched by a bishops for an opponent knight at almost
similar piece of the other side, otherwise any particular time in the game, gaining in
calculation of imbalances for both sides the process an additional positional
would amount to pretty much the same advantage, so big is the power of the pair;
thing. this always represents a further asset, as it
increases the number of game options: the

155
bishop pair side can keep the pair, but it Bb4 3.Nd5 Be7 4.Ne7 Qe7: white is
can also get rid of it to good avail largely winning, because of the bishop
- in a range of particular situations, the pair pair, although many top engines would
of bishops is valuable in other respects, for assess it as almost equal, and quite
example when simultaneously attacking probably so also many humans
the enemy king shelter, with opposite
castlings on the board, when the pair is Frequency: very frequent
able to attack the enemy king and defend
the own king at the same time as a king
safety add-on, something a pair of bishop Pair of bishops with enemy side
and knight can not do, for example, etc., having no bishops
etc.

The pair of bishops are especially valuable

in the endgame(see above-diagrammed
position), for the simple reason that in the
endgame bishop mobility is much higher
on average than knight mobility, and there
are fewer opponent pawns to attempt
restricting their activity.

It is a big misconception, though, that the

pair of bishops lacks in significant value in
earlier stages of the game, primarily the
early opening. Even there, bishops are
extremely strong, so it is always wise to
try keeping them as frequently as possible,
no matter the character of the
position(more closed, more open) and the white has larger advantage than one would
number of remaining own and enemy think; almost certainly a white win,
pawns. although black possesses above some other
relevant drawing advantages

for example, take this position, arising in

the English opening after 1.c4 e5 2.Nc3

156
a similar position with a bit different you might think position is almost equal,
configuration but in actual fact, white has large
advantage
Value: bonus, 20cps, both for the mg and
eg Value: bonus, 40cps in the mg, 30cps in
the eg, for the rook pair
Additional information: this is a very
valid positional rule. In sharp distinction to Additional information: the bonus is due
the main 2 bishops rule however, to be because:
found in almost any handbook on chess, it - the pair of rooks represent a nice tandem,
seems to be largely neglected and they are able to attack together the enemy
undiscussed. king shelter, specific enemy pawns, the
Bonus is due for the following reasons: enemy queen, etc., with the opponent
- the opponent side does not have a bishop queen quite lacking this capacity; in this
trying to match one of the bishops of the sense, it is difficult to defend such objects
pair - the pair of rooks are able to defend each
- it is not possible for the enemy side to other well, so attacking and capturing them
easily exchange one of the bishops of the is much more difficult
bishop pair, as it lacks bishop, and equal - in the presence of other pieces too, this
exchanges(same piece for same piece, will only help the rooks side, as there will
bishop for bishop) are most common in be more own pieces to coordinate among
chess, with unequal ones(rook exchange or with all of the above-mentioned
minor exchange, rook for bishop or knight advantages; for example, on the
for bishop) often requiring additional diagrammed position, the pair of rooks
tactical assets; thus, the bishop pair seems will be able to coordinate with the white
to be much more durable bishop on f3 too, so the bishop can defend
the rooks, the rooks can defend the bishop,
Frequency: infrequent the bishop and rooks can concentrate their
attack on a particular square of the shelter,
particular enemy pawn, the enemy queen,
Pair of rooks vs queen etc.

believe it or not, white is almost certainly

winning this

157
 2 minor pieces vs rook

adding just one queen each side to the last-

posted position, one might think the
white has large advantage assessment of the position will remain
more or less the same, but no, white's
Value: bonus, 20cps in the mg, 10cps in advantage has further increased
the eg, for the minors
Frequency: very frequent
Additional information: the bonus is
given because:
- the minor pieces are able to coordinate Queen and knight
among themselves, attacking in tandem
enemy pieces, pawns and squares of the
shelter
- the minors are able to defend each other,
which the lone rook is quite unable to do

With the presence of more pieces on the

board, the advantage of the minor pieces
only increases, for the simple reason that
opportunities for coordination, successful
attacks upon enemy objects and successful
self-defence further increase.

white's configuration, Qc3 and Nf3, is

somewhat better than black's
configuration, Qe7 and Bf7

Value: bonus, 15cps, both for the mg and

eg

158
Additional information: the bonus is Queen and pair of knights
given because the queen and knight are
able to successfully complement each
other in a way impossible for any other 2
pieces. As the queen combines the powers
of a rook and a bishop, controlling lines
and diagonals, and we have a knight, the
pair together combines the powers of all 3
basic pieces, rook, bishop and knight,
simultaneously controlling a wider range
of board squares. A similar feat would be
impossible for a queen and a bishop, for
example(see diagrammed position).
Downside: not always durable; the knight
could be exchanged for a bishop, leaving
only queens, or the queens, if present,
could be exchanged, leaving knight vs
bishop, for example, which will already
generally favour the bishop side. Qc3, Nd3 and Ne3 build an excellent
triplet
Of course, the rule holds true also with
other possible configurations. Value: small bonus, 7cps, both for the mg
and eg

Additional information: the bonus is

given for the same reasons as for the queen
and knight pair, good coordination, and
involves pretty much the same downsides,
associated with possible exchanges. In
distinction to the plain queen and knight
pair, here the queen already is able to
communicate with 2 own knights.

Rook and bishop

the bonus should be evaluated too, with

the caveat that, in case queens are
exchanged, that will already favour the
rook side

Frequency: frequent

159
well, white already has quite a substantial Value: penalty, -10cps, both for the mg
advantage and eg

Value: bonus, 10cps, both for the mg and Additional information: you will find
eg this feature in most wise chess handbooks.
The obvious reason for the penalty is that
Additional information: the the rooks are redundant, of same power,
configuration is bonised because: controlling squares only along files and
- both the rook and the bishop are sliding, ranks, and control of diagonals and knight
long-range, fast-moving pieces powers are lacking.
- as long-range, they are able to coordinate Downside: possible exchanges of one of
among each other even from afar, for the rooks, getting rid of the redundancy,
example to defend each other, or to attack for example, on the diagrammed position,
enemy objects/squares of the king shelter, if rooks are exchanged, that will only
which a tandem of opponent rook and benefit the pair of rooks side.
knight can not quite always do
One must take into account that the pair of
The rook and bishop pair will generally be rooks could happen on the board in quite
even stronger in the endgame due to their different configurations, with each
long-rangedness and increased mobility, configuration adding a different flavour to
however, this feature is difficult to the mix. For example, on the diagrammed
realistically account for, because of the position, the redundancy penalty will be
very high probability to transit from the fully deserved, in an imbalance involving a
middlegame to the endgame with equal pair of rooks vs 3 minors, for example, to
piece exchanges, very frequent, leaving the the natural rook pair redundancy one
overall balance unchanged. should add the additional advantage a
couple of lower-power minor pieces wield
Frequency: frequent over the rooks, and in the case of a
configuration including pair of rooks vs
Pair of rooks enemy queen, one should add the well-
deserved bonus for 2 rooks vs queen to the
ad-hoc dispensed redundancy penalty.

Frequency: frequent

the white rook pair, although connected,

looks pitiful next to the black piece tandem

160
 Pair of knights

in the endgame, even though more in

numbers, and with higher nominal material
well, the knights are so pitiful, easily a win cumulative values, the white pair can
for the opponent side easily concede a loss to the black side,
precisely because of its extreme slow-
Value: penalty, -10cps in the mg, -30cps movingness next to the fast-swinging rook
in the eg
One must bear in mind though that, in
Additional information: the penalty is spite of the fact that the redundant knight
given for the same obvious reason: the penalty is general, it receives particular
knights are redundant, controlling only and flavours in a range of specific
exclusively squares, reachable by knight configurations. For example, in case of
moves, and unable to access board squares queen and 2 knights for one side, one
along files, ranks and diagonals. should also add the bonus for the triplet to
Apart from that, the knights are slow- the general penalty, in case the 2 knights
movers, taking a lot of time to go from one are part of a larger group of minor pieces
edge of the board to the other, which is of or minor pieces and rooks pitted against an
particular significance in the endgame. enemy queen, one should also add in the
Thus, having 2 knights, if not highly relevant bonus, and the same in case of
centralised and linked to some other couple of minors including the knight pair
relative advantages, simply means being vs a pair of enemy rooks, etc.
twice as slow.
Frequency: frequent

161
 Rook, knight and bishop Queen and bishop vs queen and rook

the white pieces beautifully coordinate the white queen plus bishop are facing the
among themselves black queen plus rook

Value: bonus, 10cps, both for the mg and Value: small bonus for the queen and
eg bishop, 8cps, both for the mg and eg

Additional information: the bonus is Additional information: the bonus is

given, of course, for the excellent given because:
complementarity of the triplet: the rook, - the queen and bishop coordinate better
bishop and knight all have different - in the queen and rook, you have a partial
powers, and control squares accessible redundancy of a rook power, present in
along ranks, files, diagonals and through both the rook and the queen, while in the
knight moves queen and bishop, quite the contrary, you
have a partial presence of a pair of
Frequency: frequent bishops, with the bishop power also
available in the queen
- the bishop is a piece of lower power next
to the rook, and pieces of lower power,
when well coordinated, always have some
relative advantages to pieces of higher
power, mainly in the ability to attack them

162
 in spite of the seemingly materially
balanced position, white is easily winning
that

Value: bonus, 60cps in the mg, 20cps in

the eg, for the 3 minor pieces

Additional information: this is one of the

imbalances that capture the imagination.
Even top humans have considerable
problems playing it optimally, as
transitions from one piece configuration to
another are frequent and abrupt, and
human perception usually has difficulties
quickly adapting to changing unknown
circumstances. Besides, gameplay is far
adding more pieces basically changes from trivial. Machines, on the other hand,
nothing: the white advantage has risen would play easier materially unbalanced
further positions with complicated exchanges and
abrupt transitions, however, the problem
Please note, that the bonus is not given there, with rare exceptions, is hugely
with the imbalance queen and bishop vs insufficient material imbalance evaluation.
queen and knight, although the queen and
bishop will still partially represent a pair of The 3 pieces are due a nice overbonus due
bishops, for the very simple reason that to the following reasons:
bishops have less influence upon enemy - much better coordination in attack: the
minors. more numerous army is able to
successfully aim at and conquer enemy
Frequency: frequent objects, pawns and pieces, and squares of
the king shelter, with defence of the
opponent side being insufficient due to the
Queen vs 3 minor pieces presence of a single piece of higher power,
the queen, which alone can not defend
itself and particular board squares from
multi-focused attacks
- pretty much along the same lines, much
better coordination in defence: the more
numerous army is able to very successfully
defend its separate units, as well as vital
points in its pawn structure and king
shelter; with so many pieces, usually many
of them will mutually defend each other,
as well as a multitude of own pawns and
otherwise vulnerable king shelter squares

The much lower endgame bonus is due to

the fact that, the smaller the number of
pieces for one side, the worse their
coordination is.

163
 Queen vs rook and 2 minor pieces

this is pretty much a draw

white should easily win that one, although

the material balance somewhat even
favours black

Value: bonus, 120cps in the mg, 80cps in

the eg, for the rook and 2 minor pieces

Additional information: another

imbalance configuration that promptly
captures the imagination. As with the 3
minor pieces vs queen imbalance, here
most humans will have terribly hard time
playing such positions optimally, while
most, even top, chess engines, will fail to
make the utmost of such imbalances,
simply because of partially or entirely
and this is pretty much won for white, lacking chess knowledge, meaning the
even if white did not possess the bishop engines will rarely pick up lines involving
pair similar imbalances, going for other, much
inferior positions instead.
Frequency: infrequent
The very well-deserved bonus is dispensed
for precisely the same reasons as with the
3 minor pieces vs queen imbalance:
- much better coordination in attacking
enemy objects and particular board squares
- much better coordination in defence,
including defence among pieces, and
defence of specific board squares

The only bigger distinction with the

above-mentioned imbalance is that here

164
the drawing margin in terms of available in spite of the seeming material equality,
board material comes significantly later for white has excellent winning chances
the queen side, as the opponent has a
possession of more material even with no Value: bonus, 150cps, both in the mg and
other pieces present, including a rook, and eg, for the 2 rooks and minor
besides the presence of a rook will mean
that this side has a piece attacking along Additional information: the
ranks and files apart from pieces with configuration is bonised because:
minors' capabilities. - the higher number of pieces provide
much better coordination in attack
- the higher number of pieces provide
much better coordination in defence

Bonus is equal for the mg and eg, as, even

if no additional pieces present, the side
with the 2 rooks and a minor already has a
sufficient material availability to
dangerously threaten the opponent.

with more pieces on the board, that is an

even easier win for the rook and 2 minors

Frequency: infrequent

Queen vs 2 rooks and a minor piece

more pieces would of course only increase

winning chances for the side with 2 rooks
and minor; in fact, white is easily winning
that

Frequency: infrequent

165
 Rook vs 3 minor pieces

with more pieces present, the advantage

for the side with the 3 minors further
in spite of materially balanced position, increases; white is easily winning that
white should easily win that

Value: bonus, 70cps, both in the mg and

eg, for the 3 minor pieces

Additional information: another

intriguing imbalance. The bonus is given
for the following reasons:
- much better coordination in attacking
enemy pawns and pieces, as well as the
enemy king shelter
- much better coordination in defence,
including defence among pieces and
defence of vital board squares, primarily
the king shelter
- permanently fixing enemy pawns as
backward, gaining valuable positional
assets in the process a clear example of how a big number of
minor pieces for one side is able to make
enemy pawns backward; if it were not for
Nb3, controlling the c5 square, black
would be able to push c6-c5, getting rid of
the c6 weakness; if it were not for Nf3,
controlling the g5 square, black would be
able to push g6-g5, with some counterplay;
even h5-h4 push is not possible, even
though white does not have a pawn
challenging black's h5 pawn advance, as
both Nf3 and Bg3 control the h4 square; in
this way, all of above black pawns are
backward, and white can use these

166
positional assets to gain some more time in In distinction to the 3 minor pieces vs rook
regrouping and delivering a decisive attack imbalance, however, here the bonus is
against enemy weak pawns, pieces and significantly smaller, because the stronger
squares of the king shelter; what makes side possesses just a single non-pawn
such opponent pawns backward is the lack piece more, which renders coordination
of pieces of lower power as minors for the among pieces somewhat better, but not to
opponent side, able to support the advance the extent as a plus of 2 non-pawn pieces
of own pawns, therefore it is much would ensure.
preferable to have minor pieces than rooks
in similar constellations

Frequency: infrequent

3 minor pieces vs 2 rooks

more pieces, of course, will only increase

the edge for the side with the 3 minors

Frequency: infrequent

Rook and minor piece vs queen

well, white will always have some
additional small edge in similar positions

Value: bonus, 15cps, both in the mg and

eg, for the 3 minor pieces

Additional information: the bonus is

dispensed for the following reasons:
- better coordination in attacking enemy
pawns and pieces, as well as squares of the
king shelter
- better coordination in defence among
pieces, as well as defence of vital board
squares, basically the king shelter
- ability to make enemy pawns backward,
pretty much along the same lines as in the
case of an imbalance of 3 minor pieces vs
rook

167
 white should easily hold that, in spite of statistically, by perfect play, and a bit of
the huge material deficiency randomness, black should not win more
than 20% of the games, with the rest
Value: bonus, 60cps, both in the mg and coming to a legitimate drawn conclusion
eg, for the rook and minor piece

Additional information: the bonus is

given for the nice ability of the rook and
minor piece to coordinate among
themselves while attacking enemy objects,
pawns, pieces and squares of the king
shelter, and defending vital squares on the
board, primarily the own king shelter, as
well as for quite successfully defending
each other. A lone queen, for example, can
not capture a minor piece defended by a
rook, or a rook, defended by a minor piece,
nor it can take any enemy pawn supported
by one of those pieces.

Similar configurations frequently lead to

drawish fortresses in the endgame(see the having a bishop instead of a knight
diagrammed position). changes nothing: still pretty much drawn

With the presence of more pieces on the Frequency: frequent

board, the relative advantage of the rook
and minor piece only increases, as more
pieces guarantee better general 2 minor pieces vs queen
coordination.

in spite of the huge material deficit, white

some humans, and too many top engines has excellent drawing chances; in any
too, might be surprised to know that above case, winning such endgames is extremely
position is mostly drawn, at least very very long-winding and difficult, frequently over
close to being a perfect draw; I guess, the margin of the 50-moves chess rule,

168
everything will depend on one or 2 small
details, the eye-striking conclusion
however will always be that the material
lead by a couple of pawns for the stronger
side is somewhat unreal

Value: bonus, 40cps, both in the mg and

eg, for the 2 minor pieces

Additional information: the bonus is

given for the better coordination of the 2
minor pieces. They are able to:
- much better defend each other, making
enemy captures quite unlikely
- excellently defend different vital points
on the board, as otherwise weak own
pawns, squares of the king shelter, etc. look at how pieces of lower power are
- frequently make enemy pawns indeed very good at supporting the march
permanently backward forward of own passed pawns; currently,
- successfully support the march to white can play both c5-c6 and a6-a7, and
promotion of possible own passed pawns, the black queen can capture neither pawn,
as they can control squares on the as the minors will support them
promotion path the side with lone queen
simply can not defend With more pieces on the board, the relative
advantage of the side with the 2 minor
pieces only increases, of course, due to
improved coordination with the remaining
own pieces.

well, e5 pawn is permanently backward,

e5-e4 obviously loses the pawn, c7 pawn
is permanently backward, if it were not for
the white bishop on d5, black could have
pushed c7-c6, getting rid of the weakness, white has excellent winning chances,
g5 pawn is permanently backward too, if it although some top engines and quite a few
were not for the white knight on f2, black human players might be surprised
could have attacked on the kingside with
g5-g4, now this is impossible Frequency: infrequent

169
 Queen pair penalty for the imbalance queen vs 3
enemy pieces is not assigned, of course,
this will only show up as a penalty for the
queen pair, but that is another question,
evaluation gaps and discontinuities are not
a matter of the present work. It has to be
figured out though, if both queens get
penalised for the imbalance, and in what
precise measure.

are the white pair of queens redundant,

deserving a penalty, or, on the contrary, a
welcome constellation, due some bonus?

Value: bonus, 40cps, only for the mg

Additional information: in my evaluation

framework, a pair of queens is due a
perceptible bonus, though most wise chess in the presence of more pieces and largely
theory handbooks out there will tell you closed positions, the pair is usually
otherwise. Why should the queen pair be weaker; above configuration is a most
due a bonus? likely draw
Well, reason is simple: the pair has
unmatched by opponent pieces properties
of lightning-fast movement and
coordination, which frequently leave the
opponent king under very dangerous
circumstances, especially when the
position possesses a more open character.
That is an undisputed fact.

Note: however, the queen pair bonus is

meaningful, only if other relevant factors
are considered too. So, for example, when
one side has 2 queens, the other will
usually have more rooks and minor pieces,
where another additional bonus is
dispensed, this time going to the imbalance
of 3 minor pieces vs queen, rook and 2
minor pieces vs queen, etc. In this way, the with more open positions, especially when
presence of queens is first penalised, the enemy king is in the center, the queen
deservedly so, and then bonised. If the due pair is extremely dangerous, as the queens

170
move very fast across the entire board and
different queen checks threaten all the time

Frequency: infrequent

One side having one piece more

this is most likely won for white, although

the balance is just a single knight for 4
enemy pawns

well, white is supposed to have big

advantage, even in above simple endgame,
where, according to theory, pawns get
much more valuable

Value: bonus, 20cps, both in the mg and

eg, for the side with the piece more

Additional information: this is a simple,

but very sound, rule of thumb. The bonus
is given of course for the fact, that the
larger number of pieces will necessarily
provide better coordination. another good reason for assigning the side
The more pieces on the board there are, the with the piece more, usually a minor, the
further the advantage of the side with a bonus, is that the additionally available
piece more increases. minor piece will provide quite a
satisfactory cover to the own king, even in
the absence of a pawn shelter, as on the
diagrammed position, so that further
boosts the friendly king safety

Frequency: frequent

171
 One side having 2 pieces more One side having 3 pieces more

in spite of the generally accepted theory white should be winning this, with utmost
that pawns only get more valuable in the ease
endgame, white has excellent winning
chances Value: bonus, 100cps, both in the mg and
eg, for the side with the 3 pieces more
Value: bonus, 50cps, both in the mg and
eg, for the side with 2 pieces more Additional information: this is extremely
rare, but still happens sometimes. The side
Additional information: another very with the much greater number of pieces is
useful and true rule of thumb. Whenever bonised, of course, due to the fact that
you see one side has 2 pieces more, no those pieces provide exponentially better
matter what those pieces are, give this side coordination than the other side. With such
a sufficiently big bonus. over-excellent coordination, the own king
The bonus is due, of course, for the is completely safe, the pieces themselves
significantly better coordination among the quite safe too, even under attack, as
pieces prevalent in number, exponentially defence by other own pieces is promptly
better compared to the case with just a available, the enemy pawns are over-easily
single piece more, especially when the stopped in their march forward and
overall number of pieces is greater. effortlessly attackable and capturable,
This is somewhat redundant to also much the same as the enemy non-pawn
assessing imbalance features as queen vs 3 pieces.
enemy pieces, or, rook vs 3 enemy minors,
but, it is necessary, as it also encompasses Frequency: infrequent
positional options as the one diagrammed
above.

Frequency: infrequent

172
 Opposite colour bishops with one side the reasons top engines do not promptly
having a piece more recognise the essence of similar positions
granted the lack of correct evaluation.

The presence of more pieces will only

improve the chances of the side with the
piece more, of course.

Frequency: infrequent

Chapter VI

King safety

no matter how much surprised a bunch of

top engines and many humans will be, in
spite of the overall material balance and Well, here you are at the most interesting,
the presence of opposite colour bishops, as well as most complicated section of
that otherwise would only improve chess knowledge. Chess is basically all
drawing chances, white is easily winning about king safety, mating the enemy king,
that so the importance of this section can
hardly be overemphasised. When you
Value: bonus, 50cps, both in the mg and learn how to attack the enemy king, you
eg, for the side with the piece more will get very good results, even if you
misunderstand most of the other chess
Additional information: the elements, for the simple reason that, when
configuration will usually happen with one the enemy king is mated, it hardly matters
side having the piece more for a couple of how much material you and your opponent
enemy pawns. The bonus is dispensed for have, how many strong passed pawns,
the fact that the side with the piece more outposts, etc. you and your opponent
will easily neutralise the advance of the possess. The game is simply finished. So,
enemy pawns, as the opponent bishop will if you can learn one thing about chess,
not be able to support them on the squares please do learn how to properly attack the
of opposite colour, where the bishop of the enemy king.
side with more pieces will stop them Of course, enemy king attack is just one
unchallenged, on occasion also aided by element of king safety, albeit the most
another piece. In this way, while the pawns salient one. King safety has many other
of the side with fewer pieces will remain elements, too, the presence of a pawn
largely blocked in their way forward and shelter for the friendly king, the
ineffective, the other side will gain availability of storming pawns, different
valuable time to regroup, attain additional other features too, which are also
positional advantages and attack with its extremely important and can hardly be
own pawns. The variations are always underestimated.
long-winding though, requiring a lot of King safety is a challenge for both top
manoeuvering, and probably this is one of engines and top humans. Although top
engines play relatively well, or even

173
extremely well many positions having to Enemy king attack
do with king safety, that will be only true
of positions involving variations that are Of course, enemy king attack may take the
not very deep and including more or less form of attack by friendly pieces and
forced series of moves like captures or attack by friendly pawns, so called
checks. Whenever the associated lines are storming pawns. Here, we are only
deeper, or do not necessarily involve a concerned with attack by friendly pieces.
series of forced moves, top engines start to
regularly miss out on the best moves. One King shelter
reason being the depth, and the second one
the lack of proper knowledge. Top We have to introduce this notion before we
humans, on the other hand, seemingly go on with attacking explanations. The
recognise a wide range of patterns king shelter, strictly within our evaluation
conducive to enemy king attack and framework, but that will often overlap with
defence of the own king, but definitely not many other frameworks, are the 8 squares
all. There are king safety patterns not a immediately surrounding the king, the
single top chess player has tried so far on squares the king attacks, plus the 3 more
the board, and other that only a few squares 2 ranks in front of the king on the
players have attempted. The major same file as the king, as well as the 2
downside to human handling of king adjacent files.
safety is however the very rapidly
changing essence of what is going on on
the board. Humans get accustomed to
patterns and, with a lot of sacrifices
usually happening in and around the
enemy king shelter, the familiar patterns
get transformed too quickly and
unexpectedly, sometimes disappearing
altogether, so that undistorted perception
of transformations is very difficult to
achieve. A very specific weak point in
human attacking play is the inability, for
whatever reason, to promptly recognise
and employ sacrifices dealing with trading
minor or other pieces for mere enemy
pawns. Humans simply are unable to do
that, probably because it is so unexpected
to trade a knight or rook for one or 2 the white king shelter consists of the
enemy pawns, so illogical at the first sight, squares the king immediately attacks,
that humans simply fail to consider it. h2,g2,f2,h1,f1(a bit less than 8 in this case,
Engines, on the other hand, do such tricks as the king is on its first rank and does not
rather easy, one can certainly learn from attack any squares behind), plus the 3
engines in this respect. Humans also have squares on the 3rd rank(2 ranks in front)
significant problems with deep-running on the same file and the 2 adjacent files,
variations, especially when they involve h3,g3,f3
unfamiliar patterns. The black pieces, that attack squares of the
white king shelter, Ne5, Qf6 and Rh7, are
Further, we will examine to some length said to be attacking the enemy king
some of the most vital aspects of king shelter. Ne5 attacks the f3 square of the
safety.

174
shelter, Qf6 attacks the f2 and f3 squares,
Rh7 attacks the h2 and h3 squares.

When the king is on an edge a or h file, the

king shelter will consist of the squares the
king immediately attacks, plus the squares
2 ranks in front on the same file as the
king and the single adjacent file, plus the 3
additional squares on the same rank as the
king, one rank in front and 2 ranks in front
one file across the current king position.
This rule will account for the fact that the
king can quickly move from the edge to
the adjacent file, with enemy piece attacks
more or less remaining the same.

now, the white king shelter consists of the

h1,g1,f1,h2,f2,h3,g3,f3,h4,g4 and f4
squares; Rb1 attacks the h1,g1 and f1
squares behind the king, Nd2 attacks the f1
and f3 squares, while Qe6 attacks the h3
and g4 squares

Pieces attacking the enemy king shelter

Pieces attacking the enemy king shelter

will get the following bonus in terms of
specific piece:
queen: 50cps in the mg, 35cps in the eg
rook: 30cps in the mg, 20cps in the eg
knight: 20cps in the mg, 13cps in the eg
bishop: 15cps in the mg, 10cps in the eg
black piece attacks remain the same,
although the white king is already on the More or less, the pieces get bonus in
edge h file accordance with their material
significance. The slightly larger value for
When the king is not on its first rank, then the knight next to the bishop is primarily
the enemy pieces will be attacking more due to the fact that it is more difficult to
squares, of course, including the squares get the knight to an attacking position, the
behind the king. slow-moving knight should cross
sometimes the entire board to achieve that,
while the bishop can start attacking the
shelter with a single movement, even from
very far.

It is a major misconception that enemy

king attack should not be considered, in
case the attacking side does not have a
queen. Of course, that does not matter at
all. A combination of a couple of attacking

175
pieces of lower power, say rook and 2
minors, will do just as fine and frequently
even better.
Another major misconception is that
enemy king attack should be considered
only in the mg, or at least discontinued at
some point later in the game. Not at all; on
the contrary, as there is not anything more
important than piece attacks upon the
enemy king, such attacks, if present,
should be counted in until the very last
moment, well into the late endgame.
Sometimes, a bare king plus rook is able to
mate the opponent king, if on an edge file
or under special circumstances.

X-ray attacks upon the enemy Bc7 directly attacks g3 square and x-ray-
king shelter attacks h2 square of the white shelter, Rb2
directly attacks f2 square and x-ray-attacks
Well, although x-ray attacks of any object g2 square, Qf6 attacks f3 square and x-ray-
or the king shelter are measurably less attacks f2 square
important than direct piece attacks, they
are still valuable here, as squares of the
king shelter are important targets. The knight attack that does not fit
Any sliding piece, x-ray-attacking the anywhere
enemy king shelter, gets bonus in terms of
specific piece in the following way: Definition: knight on the 7th rank or b or
queen: 25cps in the mg, 17cps in the eg g files, with enemy king on an edge file or
rook: 15cps in the mg, 10cps in the eg rank next to the knight in the corner or on
bishop: 8cps in the mg, 5cps in the eg the same file or rank

As you quickly observe, the values are

more or less half of the numbers for direct
piece attack. Just a single x-ray-attacked
square after the first own or enemy direct
object in between the sliding attacker and
this square is considered.

above position represents this condition,

with the g7 knight the protagonist

176
Value: bonus, 12cps in the mg, 3cps in the
eg

Additional information: this should fill a

gap in attack evaluation of the enemy king
shelter. As easily seen on the diagrammed
position, while the knight does not attack
any square of the black king shelter, it is
still within the shelter itself!
This seems like a bit of a contradiction
and, as the knight is really very dangerous,
it is legitimately due its over-bonus.

Frequency: infrequent

the bishop on b2 attacks the f6,g7 and h8

Unchallenged attacking bishop squares of the black king shelter, that are
all empty.
Definition: bishop attacking 3 squares of As easily seen, because of the
the enemy king shelter, that are all empty impossibility of interposing pawns to
defend, withstanding the attack is a futile
Value: bonus, 15cps, just for the mg task.
Additional information: the bonus is due, Frequency: infrequent
as the enemy pieces will have very hard
time defending the own king. In the
present situation, there will be no pawn on Bishop shelter attacks with opposite
its 2nd rank in front of the enemy king, colour bishops
and also no pawn on the 3rd rank on the
adjacent file towards the center, so that Definition: with opposite colour bishops
interposing pawns to lessen the strength of on the board, bishop attacks on the enemy
attack is close to impossible. Without king shelter are scored higher
defending pawns, of course, the sheltering
task is even more difficult. Value: double bonus for the bishop
Simultaneously, the bishop will attack one attacking any square of the enemy king
more square on the rank where the king is, shelter is given
ensuring further penetration.
Additional information: the bonus is due
for a simple reason. As, with opposite
colour bishops, bishops of different colour
can only take part in the attack, but not in
the defence of the own king, their
attacking function only increases.
In that way, having a situation, where one
bishop attacks the enemy shelter, while its
counterpart does not do so, indeed very
much favours the attacking side, as the
defending bishop is completely useless in
defence, unable to interpose, attempt

177
changing the attacking bishop to weaken
the attack, or otherwise help the king.
Above considerations mean that, with
opposite colour bishops, both in the mg
and eg, sides should try at all costs to
attack, even if sacrificing a pawn or 2 in
the process.

in the eg, such condition is pretty much

forceful, too.
In spite of being a pawn up, white is in a
precarious situation.

Frequency: infrequent

even though a pawn down, white is much Bishop pair with kings on opposite sides
better, as the white bishop attacks the vital of the board
f7 square of the black king shelter, while
its counterpart on g7 currently attacks Definition: having the bishop pair, when
nothing, and will not be able to do so in kings are placed on opposite sides of the
the near future. board, one of them on the queen side, and
As the black bishop can in no way help in the other on the king side
the defence, by supporting the f7 square,
or by interposing somewhere, the attack is Value: bonus, 15cps, only for the mg
even more decisive. In this way, passivity
of bishops in opposite colour middlegames Additional information: the bonus is due
is tantamount to self-destruction and for the fact, that, with kings positioned on
should always be avoided. different sides of the board, and storms on
different wings, communication between
sides becomes even more important, and
bishops, as long-range pieces, are capable
of providing such efficient connection
better.
Bishops will be able to simultaneously
attack the enemy king shelter and defend
the own shelter, support the advance of
own storming pawns and stop the advance
of enemy storming pawns, etc., while the
slow-moving knight can only do one task
at a time, either defend the own king on
one side, or attack the enemy king on the

178
other. It will take the knight 2 or 3 moves Additional piece-attacking
to slow-jump between sides. considerations

In tandem, also, the bishops constitute an

excellent king cover. Rook on open edge file with enemy king
on adjacent file

Definition: rook on open edge h file with

enemy king on adjacent g file, or rook on
open edge a file with enemy king on
adjacent b file

the pair of white bishops are performing

much better with opposite-sided kings than
an enemy constellation involving a knight.
The pair of white bishops simultaneously
attack the b7 and c7 squares of the black
king shelter and defend the g3,f3,h2 and
g2 squares of the own shelter, while the the white rook on h1 represents this
black knight on c8 only defends certain particular condition; the h file is edge and
squares of the own shelter. open, and the black king is placed on the
In order to take part into the attack, the adjacent g file
knight will first have to go to e7-f5-h4, etc.
This takes time, and time is vital, Value: bonus, 40cps, only for the mg
especially with opposite-sided kings in the
mg. If not immediately advantageous, this Additional information: the very-well
condition is sure to bear fruit in the long deserved bonus is given for the fact that an
run. open edge file, in the mg, is a much more
dangerous attacking alley than otherwise,
With kings on same sides of the board, a because it is incomparably more difficult
similar bonus is inapplicable, as knights for defending pieces to organise sufficient
need just a single move to jump from a defence there. It is not easy to quickly
defensive to an attacking square, with transfer pieces to the edge of the board
fronts being close by, while bishops, in and, once the attacker has placed a rook on
order to attack, should be placed on the such an open file, mate will be very
opposite side of the board, and thus unable difficult to avoid(see diagrammed
to defend the own king. position).
Many human opening positions involve
Frequency: infrequent such a strategy, but top engines are not so
quick in discerning the value of similar

179
moves, as often the corresponding winning
lines are rather deep, while the engines
lack similar knowledge.

the white rook on g1 is on an open g file,

with the black king placed on an edge h
file; well, similarly, this one is quite
dangerous, though the mating sequence is
white is winning easily that, but quite far too long
often, even top engines have considerable
problems in similar setting to recognise the Value: bonus, 20cps, just for the mg
impending danger, as some 10-12
preparatory/regrouping moves are needed Additional information: the bonus is
until white transfers both one rook and the given for similar considerations: it is more
queen to the edge h file: white should first difficult to organise successful defence
get the 2 minors, Ng1 and Bf1, out of the close to the edge of the board, besides, the
way of the white rook on e1, and then play single enemy shelter pawn on the adjacent
Rh1, with transfer of the queen on h2 or edge file covering the king is quite
h4, or, alternatively, play Kg3 or Kh1, then vulnerable and often an easy target
move the rook on e1 to h2 via the second
rank, and only then put the queen on h4 Frequency: frequent

Frequency: frequent

Rook on g or b open file with enemy

king on adjacent edge file

Definition: rook on g open file, with

enemy king on adjacent edge h file, or
rook on b open file, with enemy king on
adjacent edge a file

180
 Rook on the same closed file as the Rook on adjacent closed file as the
enemy king enemy king

the white rook on g2 is placed on the same this time the white rook on h2 is placed on
closed file as the enemy king an adjacent closed file to the enemy king

Value: bonus, 15cps, just for the mg Value: bonus, 12cps, just for the mg

Additional information: the bonus is Additional information: bonus is given

dispensed for the fact, that this represents a for pretty much similar reasons as with the
rather dangerous configuration, while it is rook on the same closed file. This time, on
not taken otherwise into account. For the diagrammed position, h6 and g6
example, on the diagrammed position, Rg2 threaten, opening the h or g file.
does not attack directly the enemy king
shelter, as the files are closed, and even Frequency: frequent
does not attack it on an x-ray, as the knight
on g4 and the pawn on g5 stand in Queen on the same closed file as the
between, so attacking bonus for similar enemy king
attacks is not due. At the same time,
different things threaten, for example, Nf6
and Nh6 checks with opening the g file,
etc.

Frequency: frequent

181
this time, the white queen on g3 is placed Rook on adjacent semi-closed file as the
on the same closed file as the enemy king enemy king

Value: bonus, 8cps, only for the mg

Additional information: reasons similar

to above-mentioned for the rook in the
same situation apply. For example, on the
diagrammed position, white already
threatens Nf6 with queen capture or mate.

Rook on the same semi-closed file as the

enemy king

this particular time around, the white rook

on h2 is on an adjacent semi-closed file as
the enemy king

Value: bonus, 7cps, just for the mg

Additional information: similar

considerations as for the rook on a semi-
closed file identical with the file of the
enemy king apply. On the diagrammed
position, pretty much the same threats are
available.
this time, the white rook on h2 is placed on
a semi-closed file that is identical with the Frequency: frequent
file of the enemy king

Value: bonus, 10cps, just for the mg Kingside presence of pieces

Additional information: the bonus is Definition: any non-pawn piece apart

given for the fact that, while such a rook from the king itself present on the same
does not directly attack the enemy king side of the board as the enemy king. If the
shelter, as the file is semi-closed, it is still enemy king is on the king side of the
very dangerous. For example, on the board, that will make own pieces present
diagrammed position, Ng6 or g6 threaten, on the h,g,f or e files, if the enemy king is
with later opening the h file. on the queen side of the board, that will
make own pieces present on the a,b,c or d
files.

182
 require many dislocations instead, even a
knight on c2 would take 2 more moves to
attack the black shelter, not to mention
possible knights on b2 or a2. The queen on
e2 can go through f2 or e1 to h4 square to
directly attack the black shelter in just 2
moves; if it were somewhere on the queen
side, b2 for example, such an attack would
require one additional move. The bishop
on g2, after h3-h4 and g4-g5 are played,
can go to the h3 square, becoming very
active, and later even start attacking the
enemy king shelter, for example via f5,
when game gets open; if that same bishop
was somewhere on the opposite, queen
side of the board, it could basically attack
a whole lot of 4 white non-pawn pieces nothing related to the enemy shelter, even
present on the side of the board, where the after a very long sequence of reasonable
enemy king is: Rf1, Bg2, Nf3 and Qe2; the moves. The white rook on f1, after h4, g5
single black piece present on the side of and Bh3 are played, can go to the g2
the board where the enemy white king is square via f2 to represent a valuable
situated is the rook on e8 attacking feature, even though the game is
closed; if that rook were on the queen side,
Value: bonus, different for the specific such a manoeuver would necessarily
pieces, is given in the following way, only require significantly longer to execute.
for the mg:
queen: 20cps Frequency: very frequent
rook: 15cps
knight: 10cps
bishop: 5cps One open and one semi-open file or 2
semi-open files against the enemy king
Additional information: this is equally position
important in closed and open positions
alike. The bonus is dispensed for the Definition: one side having 2 adjacent
simple fact that, even if not currently files, one of them open and the other one
attacking the enemy king shelter, such semi-open, or both ones semi-open, with
pieces are much more likely to quickly the enemy king placed on one of them
start attacking it in the near future, as
transfers from the same side of the board
to attacking positions are easier and less
time-consuming to do.
For example, on the diagrammed position,
none of the white pieces, present on the
king side, currently attacks the black king
shelter. However, all of them can do so
relatively quickly. The knight on f3 can
jump to g5, starting to attack the shelter; in
case the knight was placed somewhere on
the queen side, such an attack would be
impossible in just one move and would

183
above position represents such a this time, we have the feature in the form
constellation: a file is open, b file is semi- of 2 semi-open a and b files, with black
open for white having even 2 pawns more; still, white is
winning this again, such is the power of
Value: bonus, 30cps, just for the mg the feature

Additional information: the bonus is Frequency: frequent

given for the fact that, although pieces for
the side having this bonisable feature may
not currently attack the enemy king Storming pawns
shelter, they will certainly do so very soon,
as the thoroughfares for attack already Storming pawns are really one of the most
exist. For example, on the diagrammed significant elements of chess knowledge.
position, although black has a pawn more Basically, immediately after attacks of
and the white pieces do not predominantly pieces upon the enemy king it makes sense
attack the black king position at this point to consider storming pawns. Even before
in time, they will certainly do so in the piece attacks upon enemy pieces, even
near future. The white rooks will be placed before pawn attacks upon enemy pieces,
on the open a file, or on a and b files, with and before pawn king shelter and every
gradual thrashing attack. Black can not other feature. Reason is again very simple
save that. For engines, that might mean and quite evident: storming pawns
seeing lines earlier due to improved constitute a major part of enemy king
evaluation, and for humans, one more attack and, once you attack and mate the
useful attacking pattern to recognise. opponent king, it really does not matter at
all what other things happen on the board.
Storming pawns basically play 2 main
functions in attack:
- opening up lines for attack of the pieces,
primarily through levering, and
- by coming close to the enemy king,
pressuring it, restricting the activity of
opponent pieces in defence and providing
valuable support for the own pieces in the

184
attack, often through controlling squares Unblocked storming pawns
where those pieces could land
The first of the above-mentioned functions
of storming pawns is largely due to free
pawns, storming pawns not blocked by
enemy pawns, while the second is a
privilege of non-free pawns, storming
pawns blocked by enemy pawns.
Therefore, it very much makes sense to
make a distinction between blocked and
unblocked storming pawns in terms of
evaluation.

Within the current evaluation framework,

a storming pawn will be any own pawn on
ranks 4 though 7 on the side of the board
where the enemy king is placed. Thus, if
the enemy king is on files h,g,f or e, the
king side, storming pawns will be found h5 is an unblocked storming pawn on the
on the same files on the above-mentioned 5th rank, e6 is another unblocked storming
ranks, while if the enemy king is on files pawn on the 6th rank. Both are levering
a,b,c or d, the queen side, storming pawns and helping to open files for attack upon
will occupy pretty much the same files on the enemy king; after hg6 hg6, the h file is
above-mentioned ranks. opened, after hg6 fg6, the f file is opened,
after ef7, the f file is opened, after fe6
instead, the same file is opened. Both
pawns are also able to advance further,
after h5-h6 or e6-e7. The free g4 storming
pawn is also able to advance further, but,
as it is not a lever, it is not capable of
opening lines.

Unblocked storming pawns get bonus in

terms of the following psqt:

8 0 0 0 0 0 0 0 0
7 0 0 0 0 130 120 120 100
6 0 0 0 0 30 90 60 50
5 0 0 0 0 40 80 70 60
4 0 0 0 0 25 60 50 40
3 0 0 0 0 0 0 0 0
e4,g4,f5 and h6 are all storming pawns for 2 0 0 0 0 0 0 0 0
white; the single storming pawn for black 1 0 0 0 0 0 0 0 0
a b c d e f g h
that could be considered is e5
unblocked storming pawns with enemy
king on the king side psqt(mg)

185
 8 0 0 0 0 0 0 0 0 Blocked storming pawns
7 0 0 0 0 65 65 60 50
6 0 0 0 0 15 45 30 25
5 0 0 0 0 20 40 35 30
4 0 0 0 0 12 30 25 20
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

unblocked storming pawns with enemy

king on the king side psqt(eg)

8 0 0 0 0 0 0 0 0
7 100 120 120 130 0 0 0 0
6 50 60 90 30 0 0 0 0
5 60 70 80 40 0 0 0 0
4 40 50 60 25 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0 h6 is a blocked storming pawn on the 6th
1 0 0 0 0 0 0 0 0 rank, g5 is a blocked storming pawn on the
a b c d e f g h 5th rank, and e4 is a blocked storming
pawn on the 4th rank. Blocked storming
unblocked storming pawns with enemy pawns are especially valuable, when
king on the queen side psqt(mg) advanced. There, they are restricting the
activity of the enemy pieces and greatly
8 0 0 0 0 0 0 0 0 helping with the attack and building of
7 50 60 65 65 0 0 0 0 mating nets. If a white queen is attacking
6 25 30 45 15 0 0 0 0 simultaneously the g7 square, for example,
5 30 35 40 20 0 0 0 0 it could promptly deliver mate to the black
4 20 25 30 12 0 0 0 0 king precisely because of the support of
3 0 0 0 0 0 0 0 0 the h6 pawn, if a white rook is targeting
2 0 0 0 0 0 0 0 0 the very same square, it could at least
1 0 0 0 0 0 0 0 0 deliver a dangerous check there, and any
a b c d e f g h white minor, bishop or knight, can land
with great effect on the f6 square, where it
unblocked storming pawns with enemy will be defended by the g5 storming pawn.
king on the queen side psqt(eg)
Blocked storming pawns get bonus in
terms of the following psqt:

186
 8 0 0 0 0 0 0 0 0 Unblocked storming pawns do occur on
7 0 0 0 0 0 0 0 0 ranks 4 through 7, blocked storming pawns
6 0 0 0 0 40 110 90 70 just on ranks 4 through 6, as a storming
5 0 0 0 0 30 80 60 50 pawn on the 7th rank can not possibly be
4 0 0 0 0 15 50 40 30 blocked by an enemy pawn.
3 0 0 0 0 0 0 0 0 Unblocked storming pawns are more
2 0 0 0 0 0 0 0 0 dangerous on ranks 4 and 5, where they
1 0 0 0 0 0 0 0 0 could additionally advance, while blocked
a b c d e f g h
storming pawns are more valuable on rank
6, due to the fact that, although they are
blocked storming pawns with enemy king stopped there, they have already reached a
on the king side psqt(mg) perfect square exerting maximum pressure
upon the opponent king, with blocked
8 0 0 0 0 0 0 0 0
usually meaning being more durable.
7 0 0 0 0 0 0 0 0
Blocked storming pawns on ranks 4 and 5
6 0 0 0 0 20 55 45 35
are simply too unadvanced, while being
5 0 0 0 0 15 40 30 25
0 0 0 0 8 25 20 15
stopped, and an unblocked storming pawn
4
3 0 0 0 0 0 0 0 0
on the 6th rank is by definition a passer,
2 0 0 0 0 0 0 0 0 often less durable, and besides passers
1 0 0 0 0 0 0 0 0 already do get their quite nice separate
a b c d e f g h bonus.

blocked storming pawns with enemy king Both blocked and unblocked storming
on the king side psqt(eg) pawns are extremely frequent.

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0 Storming pawns with kings on different
6 70 90 110 40 0 0 0 0 sides of the board
5 50 60 80 30 0 0 0 0
4 30 40 50 15 0 0 0 0 One of the most intriguing aspects of chess
3 0 0 0 0 0 0 0 0 play is the situation when both kings find
2 0 0 0 0 0 0 0 0 each other on different sides of the board,
1 0 0 0 0 0 0 0 0 one on the king side, files h,g,f or e, and
a b c d e f g h the other one on the queen side, files a,b,c
or d. This is the so-called opposite
blocked storming pawns with enemy king castling. Opposite castling is so extremely
on the queen side psqt(mg) interesting, precisely because of the role of
storming pawns. As the own king will be
8 0 0 0 0 0 0 0 0 castled on the other side, the pawns that
7 0 0 0 0 0 0 0 0 will storm the enemy king will not be part
6 35 45 55 20 0 0 0 0 of the own pawn shelter, so this allows
5 25 30 40 15 0 0 0 0 bravely thrusting them forward, sacrificing
4 15 20 25 8 0 0 0 0
them more emphatically, which frequently
3 0 0 0 0 0 0 0 0
leads to virulent, mind-boggling and eye-
2 0 0 0 0 0 0 0 0
catching attacks.
1 0 0 0 0 0 0 0 0
a b c d e f g h
As such storming pawns are easier to
move and sac, it very much makes sense,
blocked storming pawns with enemy king of course, to assign them higher values. In
on the queen side psqt(eg) the present framework, I would quantify
storming pawns with opposite castling to

187
be about one and a half times more h6 and e5 are openers for white; well, any
valuable than normal storming pawns, for capture, by either side, will lead to opening
both blocked and unblocked storming up the enemy king position, greatly
pawns. facilitating piece attack

Value: bonus, valid in terms of psqt, only

for the mg

8 0 0 0 0 0 0 0 0
7 0 0 0 0 0 0 0 0
6 0 0 0 0 25 30 35 40
5 0 0 0 0 15 20 25 30
4 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0
a b c d e f g h

openers with enemy king

on the king side psqt(mg)

8 0 0 0 0 0 0 0 0
opposite-castled kings with a bunch of
7 0 0 0 0 0 0 0 0
dangerous storming pawns for both sides; 40 35 30 25 0 0 0 0
6
in such a situation, it is only quite natural 5 30 25 20 15 0 0 0 0
to appreciate the storming value higher 4 0 0 0 0 0 0 0 0
3 0 0 0 0 0 0 0 0
2 0 0 0 0 0 0 0 0
Openers 1 0 0 0 0 0 0 0 0
a b c d e f g h
Definition: a pawn that is an advanced
lever and a storming pawn at the same openers with enemy king
time on the queen side psqt(mg)

Additional information: openers are

extremely useful in chess, both with same
side and opposite side castles. Reason is
obvious: opening up lines and diminishing
the enemy king shelter is a major attack
booster.
As this feature is redundant with the
presence of advanced levers, one must be
very careful when defining the size of the
bonus for both features and deciding
whether to dispense this ad-hoc bonus over
the bonus for advanced levers or,
alternatively, dispense one bonus only for
the case when advanced levers are not
storming pawns and a separate bonus for
storming pawns that are levers. In the
present evaluation framework, the bonus is

188
given over the general advanced levers
bonus.
Skipping the feature entirely with thoughts
running along the lines of 'we have bonus
for levers and another one for storming
pawns, so why have a third one', is the
wrong way to proceed, as storming pawn
levers are quite apart from plain levers,
their function is much enhanced, and very
specific, and besides they are extremely
frequent.

Frequency: very frequent

All storming pawns blocked

an alternative variation: h and f storming
Definition: 3 own pawns on files a,b and pawns blocked by enemy pawns, with the
c, or h,g and f blocked by enemy pawns, or remaining g storming pawn being
some of those blocked by enemy pawns, symmetrical twice backward pawn
with the rest being symmetrical twice
backward pawns Value: penalty, -50cps, just for the mg

Additional information: the very-well

deserved penalty is dispensed for the
obvious fact, that, in this very special case
of storming pawns configuration, all
possible lines of attack, both vertically and
diagonally, are fully closed, this stalling
the attack. In order for an attack upon the
enemy king to be successful, one needs at
least a single file against the enemy king
remaining non-closed, semi-open or open.
More files are even better, but at least a
single file is essential.
As is very easy to discern on above
diagrams, despite the presence of quite a
few, in some cases advanced storming
pawns, the opponent king really feels
h,g and f storming pawns all extremely safe.
blocked by enemy pawns
Frequency: infrequent

Edge storming pawn blocked by enemy

king

Definition: edge h storming pawn on h6,

with enemy king on h7, or, edge h
storming pawn on h7, with enemy king on

189
h8, or, alternatively, on the queen side, - the file where the king-blocked storming
edge a storming pawn on a6, with enemy pawn is is semi-closed, own heavy pieces
king on a7, or, edge a storming pawn on can not attack along this file; additionally,
a7, with enemy king on a8 even the square upon which the advanced
storming pawn resides is unattackable by
own pieces, so in a way it is better to have
an opponent shelter pawn there instead of
an own stormer
- the single remaining adjacent file to the
attacked enemy king, even if open or semi-
open, is far from sufficient to achieve a
successful attack, as a single weakness is
easily defended; any defending minor
piece can easily stop enemy heavies trying
to penetrate along that line
- it is true that the advanced king-blocked
storming pawn exerts a considerable
pressure upon the opponent king, but that
is certainly more than compensated for by
the vital file closure; as said, in this way
the storming pawn is more of a burden
h6 storming pawn blocked by the enemy than an asset
king on h7
Edge king-blocked storming pawns are the
only ones to be considered for this feature
of king-blocked storming pawns, as, going
towards the center, a g or b king-blocked
storming pawn on g3/g2, b3/b2 would
certainly be far more effective, as,
although the file upon which that pawn
resides would be closed, 2 adjacent files
for attack still do remain, possibilities to
repel attack along both are insignificant
and thus the pawn only helps with the
onslaught.

Frequency: frequent

alternatively, on the queen side and one

square upwards, a7 storming pawn
blocked by the enemy king on a8

Value: penalty, -80cps, for the storming

pawn, only in the mg

Additional information: the very-well

deserved penalty is due for the following
weighty reasons:

190
 Twice defended storming pawn
on f5 or c5

it is possible to open the h file after h2-h4

h7-h6 h4-g5 h6-g5, with the mighty f5
twice defended pawn still wielding a
twice defended storming pawn on f5 considerable pressure

Value: bonus, 30cps, just for the mg

Additional information: the bonus is

given for the following weighty reasons:
- this is a very strong, often durable
stormer, close to the enemy king and
exerting upon it considerable pressure
- the presence of such a stormer
necessarily means that there are at least 2
other own storming pawns involved in the
attack
- in case the storming pawn adjacent to the
twice defended storming pawn on the file
towards the edge of the board is free, this
will significantly boost the pawn storm
after this pawn itself advances(on the
diagrammed position, see possible h2-h4, it is also possible to sacrifice a piece, for
g4-g5 storm, with the g5 pawn becoming example after Ng5 fg5 Bg5 or, the other
an aligned storming pawn, while the way round, Bg5 fg5 Ng5, creating 2
former twice defended storming pawn on tremendous unopposed storming pawns,
f5 transforming into a defended aligned one of which supported, both free and able
storming pawn); even if it is blocked by an to move forward, which usually gives
enemy pawn, different pawn breaks, more than sufficient compensation
undermining the enemy blocking pawn are
feasible, or, on occasion, rather efficient This feature is especially useful in closed
piece sacrifices positions.

191
in above KID-like structure(basically a mainline KID structures frequently involve
reversed KID), white already has the a twice defended storming pawn, see f4
tremendous positional asset of the d3-e4-f5 above
pointed chain and, adding another
positional asset with g2-g4, creating a The feature is equally useful on the queen
twice defended storming pawn on f5, side.
white will certainly win the game, even
with best possible defence by black. Later,
a gradual onslaught, involving h2-h4, Kh1,
Rg1, Bd2, Rg2, Rag1, g5, etc., can follow,
with a bust. Even top engines however,
frequently have significant difficulties
finding such moves, as a g4 thrust, apart
from adding another storming pawn on g4,
simultaneously leaves the white king with
a pawn less within the shelter(former g2),
carrying a penalty, and the associated
variations are very deep. An useful
evaluation feature can certainly attempt at
resolving that. For humans alike, such
patterns might be useful, as even top
humans rarely do find such moves in a
range of positions.
white has big advantage, partially because
of the central bind, constituted by the d4
and f4 pawns, but also due to the
tremendous twice defended c5 storming
pawn

Overall, it is difficult to overestimate the

great value of this particular feature.

Frequency: frequent

192
 Minor piece controlling the square in
front of an own or an enemy storming
pawn

Definition: minor piece, knight or bishop,

controlling the square in front of an own or
an enemy storming pawn, provided that
square is free

within pretty much the same setting, now

g4-g5 push is impossible, due to the
defending side of this feature: opponent
bishop on e7 controlling that very same g5
square

the white knight on f3 controls the g5

square in front of the g4 storming pawn,
making the g4-g5 push possible; in case
this knight was missing, g4-g5 would fail
to h6-g5, losing a pawn

Value: bonus, 10cps, just for the mg

Additional information: the bonus is

given for the fact that, quite often, such
controls make further storming pawn
pushes, sometimes with a break, possible.
The condition the square in front of the
pawn must be free is necessary, because the value of minor pieces next to major
otherwise this stormer would be immobile ones in successfully providing this feature
and its further advance irrelevant. is easily seen above; in spite of the double
Although the bonus is small, the situation black Qe7 and Rc5 control of the g5
is very frequent, and storming pawn square, g4-g5 is still possible, not losing
advances are extremely important, so material
skipping that feature would be plain
wrong. Frequency: very frequent

193
 Filling the gap and number of own pawns close to the
king, as well as their quality, will largely
Definition: e2 or e3 pawn, with black king depend the safety of the king. Sometimes,
on the e,f,g or h files, or, alternatively, on having a lot of other good factors, but only
the queen side, d2 or d3 pawn, with black lacking a sufficiently robust pawn shelter
king on the d,c,b or a files can have very negative consequences on
the entire game, with one or 2 missing
Value: small bonus, 8cps, just for the mg pawns around the king frequently
outweighing a whole cohort of other terms.
Additional information: the bonus is due, So securing the appropriate pawn shelter is
as, while such pawns are not considered by always a priority, otherwise enemy pieces
either pawn shelter with kings usually will make short work of the king.
castled, or storming pawns, as being too Of course, the lack of sufficient number of
unadvanced, they do play role in both own pawns around the king can be
functions. compensated for by a number of relevant
So, this just fixes an ad-hoc evaluation substituting factors, like the presence of
problem. own minor pieces within the shelter
instead of pawns, the availability of
compact pawn structures on certain
sections of the board, the more closed
character of the position, etc. In this sense,
the existence of a pawn shelter should not
be absolutised, but only regarded as a nice
asset within the much larger pool of
evaluation parameters, many of which do
pertain to the realm of king safety.

Definition: within our specific framework,

the king pawn shelter will be any own
pawn within the king shelter, i.e. the 8
squares immediately attacked by the king,
plus the 3 squares on the file where the
king is and the 2 adjacent files 2 ranks
higher, provided that such a pawn is
the black pawn on e6 is both useful as a placed on ranks 2 or 3.
defence for the black king close by, and as In case the king is on an edge h or a file,
a potential storming pawn, when it reaches own pawns 2 files across towards the
the e5 square. The white d3 pawn, on the center, on f and c files respectively, on
other hand, enjoying the very same psqt, same 2nd and 3rd ranks, will be taken into
does and will do nothing of the above. account.
So the bonus is just about natural. It definitely does not make sense to
consider any own pawn on same rank and
Frequency: frequent the 2 adjacent files on more advanced
ranks than the 3rd, simply because such
pawns constitute no cover at all, the king
Pawn shelter on more advanced ranks feels highly
insecure, while such pawns are easily
Pawn shelter(also widely known as pawn attackable and capturable.
cover) is an extremely important
evaluation factor in chess. On the presence

194
the white pawn shelter consists of the with such a nice and sufficient pawn
f2,g2 and h3 pawns; the black pawn shelter, the white king feels safe even on
shelter consists of the f7,g6 and h7 pawns the central e2 square, with same being also
true for his black counterpart on even more
advanced d6 square

It is a major misconception that the pawn

shelter should be considered only in the
mg. Of course, its relative value is higher
there but, as with piece attacks and
storming pawns, this king safety factor is
relevant right to the very end of the game,
even in very simple endgames. The king
always needs some cover.

Value: bonus, 30cps in the mg, 15cps in

the eg, for any own pawn within the king
shelter

Frequency: very frequent

this time, the g4 pawn is not part of the
white pawn shelter, neither the h4 pawn is
part of the black pawn shelter

Pawn shelter should always be considered

in the center, too. Frequently, a good
central pawn shelter might compensate for
the otherwise exposed location of the king.

195
 Isolated pawn of the king shelter Doubled pawn of the king shelter

f2 and h3 are isolated pawns of the white g3 is a doubled pawn of the white king
king shelter shelter, f6 is simultaneously a doubled and
an isolated pawn of the black king shelter
Value: penalty, -20cps in the mg, -10cps
in the eg Value: penalty, -15cps in the mg, -8cps in
the eg
Additional information: the penalty is
given for the obvious fact, of course, that Additional information: the penalty is
such pawns render the shelter very due, of course, for the fact that the shelter
vulnerable. There is no connection with a doubled pawn is much less flexible.
between the pawns, it is difficult to defend For example, on the diagrammed position,
the pawns themselves, as well as for the if f2 pawn moves, the doubled g3 pawn
pawns to successfully defend any own will remain undefended, while, in order for
piece, and enemy pieces have very easy the g2 shelter pawn to take the g3 square,
access to almost any of the king shelter first the g3 pawn should move forward,
squares. and this takes time. Sometimes, in order to
successfully repel an enemy attack, shelter
Frequency: frequent pawns should have different moving
options readily available, and this is not
the case with doubled pawns. Besides,
above, g4 square is difficult to defend
without compromising the shelter, only
option being f2-f3 push, which looks
awkward; with a non-doubled white pawn
on h2 instead, h2-h3 push would easily do
the job.

In distinction to isolated shelter pawns,

frequently both humans and top engines
have difficulties with doubled shelter
pawns, mainly because the associated lines
are usually quite deep-running.

196
 Value: penalty, -20cps in the mg, -10cps
in the eg, over the penalty for the standard
backward pawn

Note: only backward pawns on their 2nd

rank are important, qualifying for the
feature, backward pawns on squares of the
shelter on more advanced ranks are
significantly less of a weakness.
Edge h or a backward pawns on their
second rank should probably receive
considerably less penalty, maybe half of
above values, as inflexibility along the
edge files is much more difficult to
exploit.

the doubled g6 black shelter pawn is so Additional information: this is a very

awkward, that, even though white plays weighty feature, though frequently
with a pawn less, it should have little underestimated by both humans and
trouble winning the game, for example engines. The penalty is due for the fact that
after g2-g4(cutting access for the black such a pawn will make the shelter much
knight on f6 to the h5 square), followed by more inflexible, depriving the side with it
a Re3-h3 manoeuver. Many engines, from possible valuable options. For
however, will have hard time seeing this. example, on the diagrammed position,
sometimes, in order to successfully defend,
Frequency: frequent white will have to push the backward f2
pawn forward, but, under the specific
circumstances, because of the
Backward pawn of the king shelter backwardness, that will be very difficult or
impossible to do. In this way, backward
shelter pawns necessarily mean less
flexibility. Which in turn means allowing
the enemy more time to regroup its pieces
and attack.

The feature is even more negative, when

the backward-maker(the enemy pawn
making the backward pawn such,
controlling the square in front of the pawn)
is a central e or d pawn.

f2 is a backward pawn of the white king

shelter

197
 white has already basically positionally
won the game, because of the black f7
backward pawn, part of the black king
shelter, and the central e5 backward-
maker, but I wonder how many humans
will quickly give such an assessment, and
how many engines will flash up a
convincing winning score?

Thus, backward shelter pawns on their 2nd

rank are tantamount to deep-running
variations.

Frequency: very frequent

this time, the backwardness of the f2 pawn Twice backward pawn of the king
is felt even more, and the shelter as a shelter
whole is more inflexible, due to the fact
that an enemy central backward-maker Definition: exclusively, f2 or c2 twice
usually means the position bears a more backward pawns, when they are part of the
closed character, and positions with more king shelter
closedness do give more time for the
attacker to regroup

Whole systems of play are frequently

decided on the existence of a backward
shelter pawn with a central enemy
backward-maker. As the associated lines
are deep or very deep, though, neither
humans, nor even top engines will often
have a clue one of the sides is already
winning.

f2 is a twice backward pawn of the white

king shelter

Note: due to specific considerations,

possibility to open the edge h or a files,
only twice backward pawns on the f and c
files on their second ranks are considered.
Other twice backward pawns of the shelter
are completely irrelevant for the feature.

198
Value: significant penalty, -40cps in the As is easily seen, this is a tremendous
mg, -20cps in the eg, over the penalty for a feature for the attacker to build, and a
standard twice backward pawn must-avoid element for the side with the
pawn.
Additional information: this is one of my
favourite evaluation features, and I have
won a countless number of games with it
against any of the top engines. The very-
well deserved penalty is due for the
following rather weighty reasons:
- the twice backward pawn makes the
shelter extremely inflexible, much more so
than with simple backward shelter pawns.
As is easily seen on the diagrammed
position, the f2 pawn can not possibly
even budge from its place, as it will be
immediately lost and a strong enemy
passer created on the en passant square.
- usually, with such a constellation, the
edge h or a file will be opened, or
possibilities for realistically opening it up
will be very high, which further increases because of the black twice backward pawn
attacking chances on f7, part of the shelter, and the
- the feature includes by definition the associated complete inflexibility of the
presence of a central enemy backward- shelter, white has already positionally won
maker on either the e or d files, and central that, though I presume not many humans
backward-makers are frequently associated will see it, while practice shows that even
with more closed positions, which in turn the very top engines are fully clueless
will give the attacker more time to regroup black is lost. White will transfer a knight
and launch a decisive assault via g4 to f6, proceed with opening the h
- a mighty minor piece outpost can be file and win, though that might take quite
installed to great effect on the twice some time, maybe 20-30 moves or so of
defended square on the 3rd rank in front of regrouping. As the lines are deep, it is not
the twice backward pawn, smashing easy to see, but the positional win is
defences around. Usually, this will be a always there.
knight, but bishop outposting there is also
sometimes possible. Capturing this minor
outpost will help in no way, as this will
automatically lead to its transformation
into an extremely strong defended
storming pawn.
- the square in front of the twice backward
pawn is also a possible penetration point
for enemy heavy pieces, be it a rook or
even a queen. On occasion, such
installation could be sacrificial, leading to
a lot of fireworks display.
- finally, the twice backward pawn of the
shelter assumes durability by definition,
which only boosts attacking options

199
 forum couple of years ago. Although many
engines will doubt white's advantage, the
gorgeous queen sacrifice, Qf6!, leads to a
forced, albeit a bit longish, mate. Check all
the variations yourselves, to get an idea of
how strong an asset an enemy twice
backward shelter pawn is.

In all, twice backward shelter pawns are

interesting to play with and involve deep-
running lines.

Frequency: infrequent

Semi-backward pawn of the king shelter

black has already won the game, because
of the white twice backward shelter f2 Definition: semi-backward pawn on the
pawn. I am not certain how many humans 2nd rank, when it is part of the king shelter
will think so, and most top engines will be
very far from seeing a decisive black Value: penalty, -8cps, only for the mg,
advantage, but the win is always there. It is over the already dispensed one for any
true, though, that it will take quite a long semi-backward pawn
time to achieve. Black should get its dark-
square bishop to f6, sacrifice it on h4 for 2 Note: but this condition will exclude semi-
enemy pawns, later transfer a knight via h7 backward pawns with the backwardmaker
to g5 and f3, with smashing attack. If being a central e or d pawn, as this
necessary, both rooks could be enrolled in particular feature is already very-well
the approaching army to support the penalised in evaluation by existing central
assault, by taking long-range aim along the backwardmakers
h and g files.
Additional information: the feature is
penalised, as this makes the shelter less
flexible, as with other backward shelter
pawns.
In distinction to standard backward and
twice backward shelter pawns, however,
the liability is much less salient.

and this is from a game of mine against

Stockfish, played on a computer chess

200
 threatens to penetrate there, with decisive
effect.

Value: double penalty as for a regular

weak spot, -20cps, just for the mg

Additional information: the higher

penalty is of course due to the fact, that
enemy piece penetration on such squares
within the shelter is even more dangerous
and unwelcome.

g2 is semi-backward pawn of the white

king shelter, making it somewhat
inflexible.
Any possible advance of this pawn, with
existing captures of the f4 pawn, might
severely compromise the shelter structure.

Frequency: frequent

Weak spots of the king shelter

Weak spots are an even bigger weakness, nothing more dangerous than an enemy
when they are part of the own king shelter. piece on such a square. This makes the
shelter much more inflexible, as the pawn
on its 2nd rank, blocked by the enemy
attacking piece, is immobile, precluding
certain defence possibilities, associated
with the pawn's advance.

f3 and h3 are weak spots, part of the white

king shelter. The enemy bishop on g4

201
 weak spots, they are still extremely useful
and performing.

Value: small bonus, distinguishing

between the bishop and knight:
- 10cps for the bishop
- 5cps for the knight

Additional information: well, the added

value is obvious, defending a critical king
safety point

Frequency: frequent

Colour deficiency with weak spots of the

a white knight on an f6 weak spot, part of king shelter
the enemy king shelter, is often even more
menacing Definition: one side having light-square
bishop and enemy side having weak spot
Frequency: frequent of the king shelter on a light square and no
own bishop the colour of the weak spot,
or, one side having dark-square bishop and
Own minor pieces defending a weak enemy side having weak spot of the king
spot of the king shelter shelter on a dark square and no own dark-
square bishop

this time, the attack of the black knight on

g5 upon the weak f3 and h3 spots of the having no bishop the colour of the weak
white king shelter is not so dangerous, as spot with the enemy side wielding such a
the white bishop on g2 successfully bishop, able to attack it, usually means this
defends both of them. This is one of the spot will be very difficult to defend.
reasons why, although fianchettos are Above, the f3 weak spot looks even
often associated with the creation of own weaker, indeed, penetration and x-raying
through it by the enemy bishop seem

202
unchallengeable, and the weakness is even If the weak spot is in the center, the
bigger, as this is a square of the king advantage of the opposite side only
shelter, closely related to king safety. increases.
Often, this will lead to mating attacks.

Value: sufficiently large penalty, -40cps,

only for the mg

Additional information: this is a very

tricky situation for the side with the weak
spot. Repelling an attack by enemy pieces,
with the enemy raking bishop the colour of
the weak spot playing a leading role in it,
is an enormous task, often unmanageable
at all. This often allows for the side with
the attacking bishop to even play with
material down, and still organise a
powerful mating assault.

black has quite some edge, although it

trails down materially by a considerable
margin. One of the main reasons for this
edge is the unchallenged bishop on h6,
firmly controlling the e3 weak spot of the
white king shelter.

Note: the feature should not be considered

with a weak spot on h3 or a3 on an edge
file, as in this case the weakness is simply
too small to be exploitable

Frequency: infrequent

even though down the exchange and King safety related queen pins
having no shallow immediate threats,
black should win at some point, due Definition: exclusively, white bishop on
mainly to the above-mentioned positional g5 or h4, black knight on f6, black queen
feature: black has the b7 bishop, the colour on e7 or d8, with black king on e,f,g or h
of the white weak spot on f3, while white file on the king side, or, alternatively,
does not possess bishop of the same colour white bishop on b5 or a4, black knight on
c6, black queen on d7 or e8, with black
This is sometimes difficult to play for king on d,c,b or a file on the queen side
humans, but, quite often, even more so for
top engines, that do not quite possess such
knowledge. As the associated lines are
usually deep-running, engines will
frequently stumble, mainly in picking up
the wrong variations.

203
 The very-well deserved bonus is dispensed
for the fact, that the pin is closely related
to the king safety of the side with the
pinned knight. As seen on both posted
diagrams, the black knights on f6 and c6
are part of the black king shelter(pertain to
squares of the shelter), so if the queen has
to move somewhere else from where it
will not be able to defend the knight, or if
the attacking side piles up more pieces to
attack the knight, after the possible bishop
capture of this knight, the pawn structure
of the black king shelter will suffer
enormously, with pawns being doubled,
which will severely compromise the black
king safety. Apart from that, usually
the king side option another black shelter pawn will get
isolated, highlighting the weakness. And
additionally, this is still a pin, so moving
the knight is also out of the question.

and the queen side alternative

Value: sufficiently large bonus, 80cps,

only for the mg white threatens d3-d4, e4-e5, winning. If it
is black's turn, that would not save the
Additional information: this is a very game either. For example, after h7-h6,
subtle feature, indeed. Many humans Bg5-h4, g7-g5, white has already a
might still have problems with it, even at winning sacrifice: Ng5! hg5 Bg5.
the very top level, and almost all top
programs completely fail to recognise such
configurations. The reason is simple: the
associated lines are usually so deep and
surprising, that precisely calculating some
20-30 moves is beyond the power of both
humans and silicon monsters.

204
 to fully recognise, that it is an utter joy to
immerse oneself in them.

Frequency: infrequent

No pawn shelter

Definition: the lack of even a single own

pawn within the king shelter on ranks 2
and 3

with a piece more, but totally broken king

shelter, lacking in pawns, and the mighty
nasty queen pin still there, black simply
can not save that. It might take a while for
a human or engine to see it, if at all, it
might take some time, even a bit more,
but, no doubt, white will win in the end.
The pin is simply so obnoxious!
Such sacs frequently lead to beautiful play.
Is not above position a beauty?

the black king possesses a nice pawn

shelter, consisting of the g7 and f7 pawns.
The white king, on the other hand, does
not have even a single pawn within its
shelter: the e3 pawn is away 2 files across,
while both the g5 and f5 pawns are too
advanced on the 5th rank to be considered
legitimate shelter pawns. This represents
the so-called no pawn shelter.

Value: large penalty, -70cps, only for the

mg

Additional information: this is a major

feature indeed, though many humans tend
although this position might look more or to sometimes underestimate it, while even
less equal, in actual fact black has the strongest programs have regular
excellent winning chances, and one of the problems with it. Of course, the penalty is
main reasons for that is the tremendous very-well deserved for the obvious fact
black pin of the g4 bishop. that the king remains fully without pawn
Sometimes, the associated lines are so cover, which, in the mg, usually leads to
deep and wide-ranging, as well as difficult disastrous consequences. The king can still

205
find sufficient cover with only a single No own pawn on the 2nd rank within
own pawn present around in a range of the shelter
situations, though extremely rarely when
no pawns at all are present.

well, the white king does not have a single

own pawn on its second rank within the
black will win this at some point, although shelter, both h3 and g3 shelter pawns
this is not currently easily recognisable. being on their 3rd rank, while the black
The reason is precisely the complete lack king still has one pawn on its second rank,
of a pawn shelter for the white king(with g7
the f4,g5 and h4 pawns all advanced),
while its black counterpart still enjoys the Value: penalty, -20cps, just for the mg
immediate contact of 2 own shelter pawns,
g6 and f7. It might take 30, 40 and even 50 Additional information: the penalty is
moves, but at some point, the position will given, of course, for the fact, that pawns
be opened, the black pieces will penetrate on the 2nd rank tend to shelter the king
and mate the white king. The white king much better than other pawns and the lack
does not have any pawn shelter on its of even a single pawn there quite often
current place, the king side, as well as in means the king will find only a partial
the center, while walking to the queen side cover. As is easily seen on the
is simply impossible because of impending diagrammed position, the white king is
attacks. quite exposed, it should go to the 2nd rank
in order to find cover, and the 2nd rank is
Frequency: infrequent usually much worse for the king than the
1st rank. Also, a g2 pawn could stop an
attacking enemy black bishop along the
a8-h1 diagonal, while any of f2 or g2
pawns could challenge an enemy rook on
its 7th rank, with both the long diagonal
and the 7th rank now entirely open to
attacks.

Frequency: frequent

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 Single own pawn on the third rank pieces will still do fine as a cover for the
within the shelter king.

Definition: a minor piece, bishop or

knight, on a square attacked by the king,
i.e. one of the adjacent 8 squares

both the white and black kings enjoy the

presence of single shelter pawns, g3 and
g7 respectively. There is a big difference
however. The single black pawn on its 2nd
rank still sufficiently covers the king, minor pieces will only strengthen the
while its white counterpart on its 3rd rank shelter, even it is already sufficiently
far from successfully will do that. robust, as above

Value: penalty, -10cps, just for the mg

Additional information: the penalty is

due for the obvious fact, that a shelter
pawn is much less effective on its 3rd rank
compared to the 2nd rank, and the truth
that 2 own pawns on the 3rd rank, with no
other shelter pawns, are still able to
successfully hold in a range of cases, while
this will almost never be the case with a
single shelter 3rd-ranker

Frequency: infrequent

Minor piece shelter

a minor piece is a useful cover, even when
Minor piece shelter is very important the shelter is compromised
indeed, especially in the mg. A minor
piece within the shelter will always
strengthen it, while, in the absence of
sufficient number of own pawns, minor

207
 both the white bishop on g3 and the black
knight on f6 provide additional cover for
their respective kings

Value: bonus, 8cps, just for the mg

Additional information: this feature is

less significant than the case with the
minor piece immediately next to the king,
but still useful

Frequency: very frequent

Minor piece shelter defence

and in the center, too, even with the Definition: minor piece, that is not part of
complete absence of own shelter pawns the own king shelter, on square, adjacent
to the king, or on square on the 3rd rank of
Value: bonus, 15cps in the mg, 7cps in the the shelter, defending a square of the
eg shelter, adjacent to the king

Frequency: very frequent Value: small bonus, 5cps, just for the mg

Additional information: the bonus is

Minor piece on the 3rd rank within the given because this might sometimes be
shelter vital for defence.

Definition: minor piece, bishop or knight,

on the 3rd rank within the shelter,
provided that the square it takes is not
attacked by the own king, i.e. the king is
on its 1st rank

although the knight on e1 is not part of the

white king shelter, it still plays a very
useful role by defending the g2 shelter
square, adjacent to the king.
In the present situation, the knight wards
off the powerful queen and bishop battery

208
along the a8-h1 diagonal, but, even if not penetration, such minors are also very
immediately under threat, minor piece much conducive to the own king safety.
shelter defence is always good, as enemy
attack could come at about any moment.

the pair of black rooks on the same open

file as the white king are efficiently
the bishop on b7, even very far away from stopped from penetration and severely
the white shelter, by defending the h1 compromising the white king safety by the
shelter square, adjacent to the king, is able excellently placed white outpost knight on
to ward off the rook battery along the h g5, heavily supported by the pawn on f4.
open file, that would otherwise simply In case the knight was not there, the
deliver mate situation of the white king would have
been very dangerous. In that way, even
Frequency: frequent with a very much shattered pawn shelter,
the king feels secure.

Minor outpost stopping enemy rook on Frequency: infrequent

an open file, with own king on the same
or adjacent file as the rook
Immobile shelter pawns
Definition: minor outpost on its 4th, 5th or
6th rank, supported by a pawn, with an Definition: pawns on the 2nd rank, part of
enemy rook on the same open file the king shelter, blocked by an enemy
attacking it, provided the rook is more piece
advanced from the point of view of the
minor, and positioned on the same or an
adjacent file to the enemy king

Value: bonus, 15cps, just for the mg, for

the outposted minor, over the already
dispensed one for the regular condition

Additional information: the bonus is due

because, apart from stopping enemy rook

209
h7 is an immobile shelter pawn on its 2nd and g7 too
rank
Value: penalty, -20cps, just for the mg

Additional information: the very-well

deserved penalty is due because:
- immobile shelter pawns make the shelter
less flexible, as shelter pawns need to
move sometimes, in order to defend
- the shelter pawn immobility is very much
tactically relevant, as they deprive the king
of precious breathing space

Although nothing immediately menacing

might be visible at the moment, this
condition certainly bodes nothing well for
the king.

f7 is another one

210
although white is a whole minor piece up, in case the shelter had not been that
and nothing specific threatening the white immobile, and the king had a safe haven
king is seen at the moment, black is going square somewhere on the 2nd rank.
to win after Re6-h6, Ra8-e8-e6, followed
by a queen sacrifice on h2. This feature is always tactically relevant.
And white can do nothing to prevent this.
The main reason for the loss will be
precisely the extremely inflexible white
king shelter, where none of the pawns can
move at all. In order to defend, pawns
should be able to move, and this is not the
case in the present situation.
On the other hand, the pawn storm h7-h5-
h4 gives nothing, as after hg3 fg3, the f
shelter pawn is gone and already not
inflexible, making the shelter much more
acceptable as a whole and connecting both
white heavy pieces on the 2nd rank on the
queen side to the defence.

timely immobilisation of the shelter

always helps. Black wins by force after
Bg3!, immobilising the shelter g2 pawn
and threatening Qh4. In case the g2 pawn
is not immobilised, white could have
found some counterplay after, for example,
fg4 hg4 g3

Frequency: frequent

King on a fully closed side

Definition: own king on one of the a,b,c

although white is a pawn up and the black or d files, with a,b,c and d files all closed
king is completely unsheltered by pawns, with pairs of blocked pawns; or, own king
white is definitely going to lose, after a on e,f,g or h files, with e,f,g and h files all
timely pawn break by black on the queen closed with pairs of blocked pawns
side, and one of the main reasons for that
is the inflexible white king shelter,
especially in the form of the g2 pawn,
immobilised by the black bishop on g3.
With time, after the queen side break,
black will start threatening with mate on
the first rank, and that threat, coupled with
threats upon other vulnerable objects, will
be very difficult to neutralise indeed. Such
a threat would have been much less severe,

211
the white king on g1 finds itself the king on d2 represents this condition.
conveniently placed on a fully closed side The king is on the central d file, and the
of the board file where it is, the d file, is closed by the
(as all own and enemy pawns on the king d5/d6 pair of blocked pawns, similarly as
side are blocked, this makes enemy heavy the 2 c and e adjacent files, respectively by
pieces' attacks along the files on that side the c4/c5 and e4/e5 blocked pawn pairs.
practically impossible for the time being,
with enemy minor pieces' access to that Value: bonus, 15cps, just for the mg
side much more difficult too; this feature is
useful with opposite castling, as otherwise Additional information: the bonus is
both kings should get the bonus) closely related to king safety and is given
for the obvious fact, that this configuration
Value: large bonus, 30cps, only for the mg makes the king pretty much safe, although
it is in the very center of the board. As
Additional information: well, as you see easily recognised, enemy attacks along the
from the diagrammed position, the white closed central files around the king are
king feels safe, even though there are no close to impossible, so getting access to
close own pawns sheltering it. You might the king becomes much more problematic.
think this is stupid, but in chess, every This is a feature that can certainly
single feature matters. compensate for the exposed location of the
king and help choose lines with other
Frequency: infrequent positional assets involved.

Exposed king with blocked center

Definition: king on central e or d file, with

the file where it is and the 2 adjacent files
all blocked by enemy pawns

212
in spite of the abundance of potential the e4 strong defended pawn pretty much
attackers, the white king feels quite safe in nicely shelters the white king, in spite of
the center, with files around it closed by its unenviable position
pairs of blocked pawns. This might be
used to gain valuable positional assets, for Frequency: infrequent
example after a2-a4, binding the b7 pawn.

Frequency: infrequent King on semi-central file, sheltered by a

defended pawn

King in the center sheltered by defended Definition: king on the c or f file, with
pawn own defended pawn on the 3rd rank on the
same file
Definition: king on e or d file, with own
defended pawn on the same file on the 3rd, Value: tiny bonus, 4cps, just for the mg
4th or 5th ranks
Additional information: the bonus,
Value: small bonus, 7cps, only for the mg although microscopic, is due for the
sheltering abilities of the pawn with a
Additional information: the bonus is due somewhat exposed king.
for the obvious fact that this improves the Of course, defended pawns are destroyed
king's safety, even if marginally. It is more trickier than non-defended ones.
difficult for the enemy attacking pieces to
reach the king, when a defended pawn
shelters it from frontal attacks. In order to
get to the king, one should first possibly
destroy the strong pawn.
This might add nuances to one's king
safety, as well as the general evaluation of
positional trade-offs.

213
 bishop on b2, with own king on the a,b or
c files.
For black, black bishop on g7, with own
king on the h,g or f files, or, alternatively,
and again purely theoretically, black
bishop on b7, with own king on the a,b or
c files.

the king on f2 gets the bonus for the f3

defended sheltering pawn.
Indeed, although relatively exposed, and
under sufficiently heavy attack by enemy
pieces, the white king feels more or less
safe.

Frequency: infrequent
a kingside fianchetto for white and a non-
kingside-fianchetto development for black
Kingside fianchetto

Kingside fianchetto is one of the most

important aspects of chess knowledge.
Actually, almost all top players throughout
the years have preferred openings, both for
white and black, including a kingside
fianchetto. And that for a reason. Kingside
fianchetto offers the player implementing
it advantages other opening systems are
simply unable to offer. While top humans
do understand very well the preponderance
of this feature, even the very top of chess
engines are largely unaware of its
significance. In almost no opening system,
if left without a book, engines will choose
a development including the kingside
fianchetto. kingside fianchetto is also possible on the
queen side, though very rarely seen in
Definition: white bishop on g2, with own practice
king on the h,g or f files, or, alternatively,
and purely theoretically, as such cases Value: bonus, 15cps, just for the mg
would only happen very rarely, white

214
Additional information: it is difficult to 4(!) different enemy objects: the knight on
overestimate the all-importance of c6, the rook on a8, as well as both pawns
kingside fianchetto. The bonus is due for a on d5 and b7. Currently, there are no
couple of reasons: immediate tactical threats, but at some
- the fianchettoed bishop attacks and x- point, that will definitely matter. Apart
ray-attacks a multitude of objects on the from that, the bishop x-ray-attacks the vital
long diagonal, both enemy pieces of central e4 and d5 squares. Look also at the
different value and enemy pawns white king shelter. Can you imagine a
- the fianchettoed bishop, often in concert better cover for the king? The shelter,
with own shelter pawns, represents an apart from pawns, also includes a minor
excellent king-defending feature piece in the form of the bishop, which
- the fianchettoed bishop attacks and x- additionally strengthens it, but what is
ray-attacks a number of important central even more important is the excellent
squares, with minor piece control of center harmony of control between the bishop
being a vital element of the struggle; a and the shelter pawns on f2,g3 and h2,
fianchettoed bishop on g2 will attack and with the bishop controlling light squares
x-ray-attack the central e4 and d5 squares, and the pawns dark squares around the
while a fianchettoed bishop along the shelter, thus ensuring enviable
alternative long diagonal, on b2, will complementarity of defence. There is
attack and x-ray-attack the central d4 and really no better shelter than this one, all
e5 squares other possible king shelters are only
- finally, the fianhettoed bishop does all of inferior.
the above in a single move, thus providing
great efficiency of function A wide range of openings, open and
closed, both for black and white, include a
kingside fianchetto. It is sufficient to only
mention the Catalan, the Reti, the King's
Indian Defence and the Gruenfeld, to
highlight the importance of this method of
development, but the method is also
applicable in a long series of other popular
openings, like the Sicilian, the English,
etc. Actually, as a matter of fact, a
kingside fianchetto is feasible in almost
any existing opening, regardless of
whether theory would recommend that or
not. More than that, it is not only feasible,
but on most occasions the best line of play.

taking even the simplest opening

implementation of kingside fianchetto, for
example after 1.g3 d5 2.Bg2 Nf6 3.Nf3 c5
4.0-0 Nc6, white already has quite some
edge, although even top engines will have
very hard time figuring that out, as it takes
an amount of time until white's advantages
become evident. As is easily seen on the
diagram, the bishop on g2 x-ray-attacks

215
 thanks to the challenge of the c4 pawn
upon the d5 square, also greatly helps in
undermining the central black d5 pawn. It
is difficult to successfully defend that
pawn, but relinquishing center control with
d5-c4 is even worse.

why would Kasparov and Fischer always

prefer the King's Indian Defence? Well,
you see that mighty penetrating bishop on
g7, that has already, at such an early stage
of the game, taken aim at the white knight
on c3, the white rook on a1, the white
pawns on d4 and b2. Owing to the x-ray
control of Bg7 upon the central e5 square, even in fully closed openings, like for
black is able to promptly play e7-e5, even example this English line: 1.c4 e5 2.Nc3
though it does not have sufficient direct Nf6 3.e4 Nc6 4.g3 Bc5 5.Bg2 0-0 6.Ne2
control of that square. d6 7.h3 Be6 8.d3 h6 9.0-0 Qd7 10.Kh2,
the fianchettoed bishop on g2 plays a
major role. Apart from defending the
otherwise vulnerable h3 square, it also
critically controls the central d5 square
along an x-ray, so, black is not able to
counter-break with d6-d5 even after first
removing the knight on c6 and supporting
the break with c7-c6, because white will
still have sufficient over-control of d5 in
the form of the central bind of the pair of
c4 and e4 pawns, the knight on c3 plus,
very vitally, the x-raying bishop. Had it
not been for the bishop, black could very
well have succeeded. Now, white threatens
to continue the attack with f2-f4, f4-f5, g3-
g4, etc., getting an overwhelming position.
Later, white should almost certainly win
the Catalan, both the open and closed that, though even top engines will have the
systems of play, for example after 1.d4 e6 greatest of difficulties recognising white's
2.Nf3 Nf6 3.g3 d5 4.Bg2 Be7 5.c4, is also advantage.
very favourable for white. In the present
case, apart from attacking enemy pieces on In conclusion, kingside fianchetto is easily
the long diagonal, the white bishop on g2, the most efficient opening technique.

216
Frequency: very frequent trapped white rook on the queen side; this
time, the rook has 3 available mobile
squares
Trapped rook

Definition: white king on e1,f1 or g1

squares, with white rook on f1,g1 or h1
squares, or, alternatively, on the queen
side, white king on e1,d1,c1 or b1, with
white rook on d1,c1,b1 or a1, provided
that the white rook on the king side has
less than 3 available mobile squares, or, if
the white rook is on the queen side, it has
less than 4 available mobile squares

above, the white rook is already not

trapped, as it has 4 available mobile
squares. This will allow it to swing via the
a3 square to the center of the board or the
king side, or at least start sitting in front of
the own pawns on the queen side,
simultaneously freeing valuable shelter
space for the king.

Value: sufficiently large penalty, -70cps,

just for the mg
trapped white rook on the king side; please
note, that the rook has just a single Additional information: this is a major
available mobile square evaluation feature. The penalty is due for
the following reasons:
- as the name itself suggests, the rook is
trapped, with restricted mobility, much
less active and unable to go to the central
files of the board, where it will be much
better placed, because the own king blocks
its route towards the center
- it is difficult to play without a whole
heavy piece in the mg, so the side with the
trapped rook will usually find itself under
dangerous attack, even if it has material
superiority
- the king itself, especially if castling
rights are lost, will have to stay in the
center or close to the center of the board

217
for quite some while, which bodes nothing
well for its safety
- finally, it usually takes a significant
amount of time until the king and rook
manage to regroup so that the rook is not
any more trapped and the king goes to a
safer place, and couple of tempos in chess,
especially in the mg, are mostly decisive

the black bishop on a6 attacks the f1

square between the white king and rook,
temporarily preventing kingside castling

although white plays with a pawn less, it is

most certainly winning, mainly because of
the trapped black rook on h8. In order to
free the rook and get the king to a safer
place, black should at least play h7-h6, g7-
g6, Be7-d6, Kf8-g7, which is a whole lot
of tempos. In the meantime, white will
certainly have started mating the opponent.

Frequency: frequent

the black knight on c3 attacks the d1

Temporary prevention of castling square between the white king and rook,
temporarily preventing queenside castling
Definition: white king still uncastled
kingside, but having castling rights Value: penalty, -20cps, just for the mg
kingside, with any enemy piece attacking
the f1 or g1 squares, or, alternatively, on Additional information: the penalty is
the queen side, white king still uncastled due for the fact that this feature will
queenside, but having castling rights deprive the king of the possibility to
queenside, with any enemy piece attacking quickly castle on the relevant side, going
the d1 or c1 squares to a safer place. Although this is nominally
just a temporary situation that will fade
away with the removal of the enemy piece
thwarting castling or closing the line of

218
attack of a distant enemy slider by dint of Ability to immediately castle
interposition of a pawn or piece, it is still
usually extremely unwelcome. There is no Definition: king having kingside castling
guarantee the enemy piece preventing rights, with all squares between the king
castling will be destroyed, or its line of and the kingside rook free, or,
attack closed, and in case the king does not alternatively, on the queen side, king
have a good alternative sheltering option, having queenside castling rights, with all
that will mean the king will have to stay in squares between the king and the
the center of the board for a shorter or queenside rook free
longer while, which in the mg is frequently
disastrous.
Of course, this is a better situation in
comparison to entirely losing castling
rights due to a king or rook moves, but still
very negative and to be avoided whenever
possible.

the white king is currently able to

immediately castle both kingside and
queenside. In distinction, his black
counterpart is unable to immediately castle
either king- or queenside. This will
increase the options for the white king to
find a satisfactory shelter, the same not
this is from a famous game Nezhmetdinov being true for the black king, at least
vs Tal, with Nezhmetdinov playing white. currently.
Main reason why black is losing this is the
inability of the black king to find a safe Value: small bonus, 10cps, just for the
haven on one of the wings. Castling mg, for each immediately available
queenside is too dangerous, while kingside castling option
castling is thwarted by the attack of the
knight on h6 upon the g8 square, so the Additional information: the bonus is
black king has no other choice but to stay obviously due for the increased ability of
in the center. That will be baleful, of the king to quickly find safe cover in one
course. of the corners of the board.
Although many writers will consider
Frequency: infrequent having castling rights as more important,
no matter if own pieces currently block
such a possibility, I guess simply having
castling rights is not sufficient, as it might
take quite a bit of time, until the king goes

219
to safety, or even it might be better for the shelter, for the very obvious and simple
king to stay in the center. With immediate fact that this might lead to material gains.
castling possibility, most of above- Thus, attacks upon enemy pieces should be
mentioned concerns are solved. very properly assessed.
Engines usually see captures rather easily
Frequency: frequent due to their search, humans, on the other
hand, even the very very top, quite often
make, even severe, tactical mistakes,
because of underestimating a specific
threat factor, having to do either with
Chapter VII direct or x-ray enemy attacks.
Attacks upon pieces are intrinsically
associated with tactics, so that anyone
General piece activity and wishing to learn tactics well, should
concentrate their attention on existing
coordination board piece and pawn attacks, as well as
threats. That might not be easy at first, and
might even take a long practice until all
This chapter will include a wide range of concepts sink in, but will undoubtedly pay
evaluation features, pertaining to the realm off abundantly, as tactics are extremely
of piece activity and piece coordination, important in chess.
such as piece and pawn attacks and threats,
defence among pieces, positional Direct attacks upon enemy pawns and
occupation of vital board lines, specific pieces
piece constellations relating to increased
positional pressure, etc. Within our evaluation framework,
It is difficult to overestimate the different piece types directly attacking
importance of such terms. Many of them, specific enemy piece types get the
primarily attacks and different x-ray attack following bonus points:
features, have strong tactical connotations,
others, like placing rooks on open files, are pawn attacks queen: 150cps in the mg,
of a more positional nature, but all of them 100cps in the eg
have enormous influence on the game. pawn attacks rook: 80cps in the mg, 65cps
It really does not make sense to know by in the eg
heart all the relevant pawn features, and pawn attacks bishop: 60cps in the mg,
fail in appropriately assessing elements, 45cps in the eg
pertaining to general piece activity, simply pawn attacks knight: 60cps in the mg,
because all evaluation elements are part 45cps in the eg
and parcel of the same overarching chess
architecture. So, when learning about
certain features, do not forget about the
rest.

Attacks among pieces

Well, there is really nothing more

important than attacks upon enemy pieces,
apart from attacking the enemy king

220
the white pawn on c5 directly attacks the the white knight on b3 attacks the black
enemy queen on d6. The queen will have pawns on a5 and d4
to retreat, otherwise it will be lost.

the black knight on c3 attacks the white

the black pawn on c6 has just forked the rook on b1 and the white bishop on e2.
white rook on d5 and the white bishop on Another fork.
b5. Unless concrete tactics exist, one of
those will perish. Of course, forks are just bishop attacks queen: 100cps in the mg,
double attacks. 70cps in the eg
bishop attacks rook: 50cps in the mg,
knight attacks queen: 110cps in the mg, 35cps in the eg
75cps in the eg bishop attacks knight: 30cps in the mg,
knight attacks rook: 50cps in the mg, 20cps in the eg
35cps in the eg bishop attacks pawn: 10cps in the mg,
knight attacks bishop: 30cps in the mg, 7cps in the eg
20cps in the eg
knight attacks pawn: 10cps in the mg, 7cps
in the eg

221
the white bishop on e2 attacks the black the white rook on c5 attacks the black
pawns on a6 and h5 pawns on a5,c6 and d5

the black bishop on d6 attacks the white the black rook on d3 attacks the white
queen on a3 and the white knight on f4 queen on d1 and the white bishop on g3

rook attacks queen: 90cps in the mg, 60cps queen attacks rook: 50cps in the mg, 35cps
in the eg in the eg
rook attacks bishop: 30cps in the mg, queen attacks bishop: 30cps in the mg,
20cps in the eg 20cps in the eg
rook attacks knight: 30cps in the mg, queen attacks knight: 30cps in the mg,
20cps in the eg 20cps in the eg
rook attacks pawn: 10cps in the mg, 7cps queen attacks pawn: 10cps in the mg, 7cps
in the eg in the eg

222
the white queen on f4 attacks the black the white king on g1 attacks the enemy
rook on d2, the black bishop on f5, and the rook on f2 and bishop on g2 in the mg
black pawn on c7
The king attacking/capturing properties are
king attacks queen: 20cps in the mg, 30cps especially useful in the eg, where the king
in the eg enjoys less danger and more freedom in
king attacks rook: 50cps in the mg, 65cps movement. Attacking enemy pawns there,
in the eg passers or otherwise, is always a big plus.
king attacks bishop: 30cps in the mg,
40cps in the eg
king attacks knight: 30cps in the mg,
40cps in the eg
king attacks pawn: 5cps in the mg, 20cps
in the eg

Well, in spite of what some readers might

think, the king should also be very actively
involved in attacking and capturing enemy
objects. Quite frequently, this might decide
the outcome of the game.

the white king on c5 attacks the enemy

pawns on b5 and c6, as well as the enemy
bishop on d5 in the eg. Precisely because
of those abundant attacks, white is able to
capture with the knight both pawns.

Note: of course, it does not quite make

sense to consider attacks upon same type
pieces, for example rook attacking enemy

223
rook, or knight attacking enemy knight,
simply because the condition will be
mutual and self-scoring

In general, the attacking values more or

less follow the material value of the
attacked piece, which is just about natural.
As a rule, the mg numbers will be
somewhat higher, due to abundant tactics
in that stage of the game, though with the
king things stand opposite: the king
deserves bigger numbers in the eg, as it is
more active there.

Frequency: very frequent

there is certainly a distinction between the

Penalty for pieces attacking an enemy white bishop attacking the black h5 and b5
defended pawn pawns, and the same goes true for the
white rook attacking the enemy f4 and b5
Definition: any own piece attacking an pawns. Not pawn-defended pawns are
enemy pawn, defended by another enemy much more vulnerable, of course, the b5
pawn pawn, on the other hand, is almost not a
relevant target.
Value: small penalty, specific for the
different pieces:
-5cps in the mg, -4cps in the eg, for the
knight and bishop
-8cps in the mg, -6cps in the eg, for the
queen and rook

Additional information: those penalties

aim at subtracting some of the bonus value
given for a piece attacking an enemy
pawn, making distinction between pawn-
defended and not pawn-defended ones.
Of course, this is very reasonable, as
pawn-defended enemy pawns are a much
less vulnerable target, sometimes to the
point that it is even harmful to attack them.

similarly, d6 and f6 black pawns are quite

reasonable targets for the white queen and
knight, much less so the g5 and e5 pawns

Frequency: very frequent

224
 Forks specific pawn or piece might be easily
saved by moving it somewhere else.
Within our evaluation framework, forks
will not be considered separately, as a fork
in itself represents nothing more but a
double attack upon enemy pieces. As
double attacks are sufficiently well seen by
the respective bonus points for each attack,
the fork automatically receives its bonus.
I do not find any necessity to assign an
additional bonus for forks.

Hanging pawns and pieces

Definition: any own piece or pawn,

attacked by any enemy piece or pawn,
including the king, and not defended by
any other own piece or pawn
the black queen on a5 and the black knight
Value: over-penalty, above the already on b2 are both hanging, as attacked by the
existing one for direct piece/pawn attacks, white bishop and not defended by any own
valid with the following array: pawn or piece. The black rook on d4,
however, is not a hanging one, as, while
hanging queen: -30cps in the mg, -20cps in under enemy attack, it is still defended by
the eg the friendly pawn on c5.
hanging rook: -20cps, in the mg, -17cps in
the eg
hanging bishop: -10cps in the mg, -7cps in
the eg
hanging knight: -10cps in the mg, -7cps in
the eg
hanging pawn: -3cps in the mg, -2cps in
the eg

Additional information: the penalty is

given for the obvious fact that such an
enemy-attacked and undefended pawn or
piece will be easily capturable by the
opponent, gaining in material.
As it is not clear under the specific
conditions whose turn it is, the penalty is
just general and rather small. In case the
attacked object's side is not on the move, the black pawns on a5 and e3 are both
of course, the numbers might be much hanging, as attacked by the white knight
bigger, almost the size of the object's on c4 and not defended by any friendly
material value, as the object will be lost piece or pawn. The black pawn on d6, on
one way or another. With the side with the the other hand, is not a hanging one, as
attacked object on the move, however, the being defended by the black bishop on f8.

225
Frequency: frequent queen x-ray-attacking knight: 10cps in the
mg, 7cps in the eg
queen x-ray-attacking pawn: 3cps in the
X-ray attacks mg, 2cps in the eg

X-ray attacks are an extremely important

tactical element, widely used by engines
and somewhat difficult to grasp for
humans of any strength alike.

Definition: attacks of sliding pieces upon

enemy pawns and pieces along their ray of
action past the first object they encounter

Value: bonus is given with the following

array, making distinction between cases
when the intermediary object is an enemy
or an own piece:

1) enemy piece in between

bishop x-ray-attacking queen: 33cps in the the white bishop on f3 directly attacks the
mg, 23cps in the eg black knight on d5 and x-ray attacks the
bishop x-ray-attacking rook: 17cps in the black rook on a8
mg, 12cps in the eg
bishop x-ray-attacking enemy bishop:
10cps in the mg, 7cps in the eg
bishop x-ray-attacking knight: 10cps in the
mg, 7cps in the eg
bishop x-ray-attacking pawn: 3cps in the
mg, 2cps in the eg

rook x-ray-attacking queen: 30cps in the

mg, 20cps in the eg
rook x-ray-attacking enemy rook: 15cps in
the mg, 10cps in the eg
rook x-ray-attacking bishop: 10cps in the
mg, 7cps in the eg
rook x-ray-attacking knight: 10cps in the
mg, 7cps in the eg
rook x-ray-attacking pawn: 3cps in the mg,
2cps in the eg the white rook on c1 directly attacks the
black bishop on c3 and x-ray-attacks the
queen x-ray-attacking enemy queen: 25cps black knight on c7
in the mg, 18cps in the eg
queen x-ray-attacking rook: 17cps in the
mg, 12cps in the eg
queen x-ray-attacking bishop: 10cps in the
mg, 7cps in the eg

226
 queen x-ray-attacking knight: 6cps in the
mg, 4cps in the eg
queen x-ray-attacking pawn: 2cps in the
mg, 1cp in the eg

the black queen on a6 directly attacks the

white rook on c4 and x-ray-attacks the
white pawn on e2

2) own piece in between

the white bishop on g2 x-ray-attacks the
bishop x-ray-attacking queen: 20cps in the black rook on a8
mg, 14cps in the eg
bishop x-ray-attacking rook: 10cps in the
mg, 7cps in the eg
bishop x-ray-attacking enemy bishop: 6cps
in the mg, 4cps in the eg
bishop x-ray-attacking knight: 6cps in the
mg, 4cps in the eg
bishop x-ray-attacking pawn: 2cps in the
mg, 1cp in the eg

rook x-ray-attacking queen: 18cps in the

mg, 12cps in the eg
rook x-ray-attacking enemy rook: 9cps in
the mg, 6cps in the eg
rook x-ray-attacking bishop: 6cps in the
mg, 4cps in the eg
rook x-ray-attacking knight: 6cps in the
mg, 4cps in the eg the white rook on e6 x-ray-attacks the
rook x-ray-attacking pawn: 2cps in the mg, black bishop on a6
1cp in the eg

queen x-ray-attacking enemy queen: 16cps

in the mg, 10cps in the eg
queen x-ray-attacking rook: 10cps in the
mg, 7cps in the eg
queen x-ray-attacking bishop: 6cps in the
mg, 4cps in the eg

227
 X-ray attacks past the second
intermediary object

Of course, x-ray attacks also make sense in

the case of more distant attacks, when the
intermediary objects are more than one.
The attacks are still real, but much less
significant, for the simple fact that it takes
time until a couple of own or enemy pieces
are removed until the slider is able to
capture the distantly x-ray-attacked piece.
Thus, the bonus values will be very small
and in many cases not really matter. Still,
when the distantly x-ray-attacked object is
an enemy piece of sufficiently high power,
such as queen or rook, the x-ray attacks
the black queen on h6 x-ray-attacks the might be quite relevant.
white knight on c1
Value: about half of the average bonus for
Additional information: well, the bonus x-ray attacks with a single object in
is due, as the enemy objects under non- between, when the intermediary objects
direct attack past the first object are really are 2, no matter if own or enemy ones(it is
under attack, but not an immediate one. In really difficult to make a distinction here).
order for a capture to ensue, a move by Thus, an attacked enemy queen will score
one of the sides should be made around 15cps or so, an attacked enemy
beforehand. This takes time, sometimes is rook some 10cps, etc.
not feasible at all, and so the attacking With more than 2 intermediary objects, the
values are much smaller than with the bonus points fall very small, so hardly of
regular case of direct attacks. Still, the big significance, for example an x-ray-
attacks are completely real. attacked enemy queen with 3 objects in
It certainly makes sense to make a between will give only about 8cps or so,
distinction between x-ray attacks upon with the main scoring rule being dividing
enemy objects with own and enemy pieces by 2 the existing bonus for any further
in between, simply because the condition addition of interposed pieces.
with an enemy piece or pawn in between is On second thought, those are not such
much more severe. It offers the possibility small values, after all, 10cps is a pretty
to capture one of the attacked objects later, good factor with so many interposing
even if the other one is removed from the objects, bearing in mind other relevant
ray. With an own object in between along positional factors with similar values and
the attacking ray of action of the slider, the quite evident characteristics. So, it would
removal of the enemy piece under x-ray be nice to still consider also more distant
attack simply leaves no enemy pieces x-ray attacks, unless your head overboils
capturable. Thus, the first condition is or your engine crashes.
much more tactically relevant.

Frequency: very frequent

228
the bishop on g2 attacks the enemy rook the rook on b8 x-ray-attacks the white
on a8 with 2 objects in between, the pawn pawn on b2 with 2 objects in between, the
on d5 and the knight on c6 white knight on b4 and the black bishop on
b5

now, already the intermediary objects are

3, adding the black b7 pawn the black queen on h8 x-ray-attacks the
white knight on a1 with 3 objects in
between, the black pawn on e5, the white
pawn on c3, and the white bishop on b2.
The white bishop on b2, on the other hand,
x-ray-attacks the black queen on h8 with
just 2 intermediary objects, the white pawn
on c3, and the black pawn on e5.

229
 Safe checks

Value: bonus, specific for the different

checking pieces.

safe queen check: 60cps in the mg, 40cps

in the eg
safe rook check: 40cps in the mg, 30cps in
the eg
safe knight check: 30cps in the mg, 20cps
in the eg
safe bishop check: 15cps in the mg, 10cps
in the eg
safe pawn check: 10cps in the mg, 10cps
in the eg

the white rook on d1 x-ray-attacks the

black queen on d8 with 6(!) intermediary
objects. The same is true for the black d8
queen, attacking the white rook on d1.

Frequency: frequent

Checks

Checks are, of course, direct attacks by

pawns and pieces upon the enemy king.

Checks are indeed very important, as

checking the king certainly increases the
possibility to endanger the enemy king,
compromise its safety, and even deliver safe knight check
mate.
It is quite relevant to split the evaluating
conditions between safe and unsafe
checks, checks given on a square not
defended by any enemy pawn or piece,
apart from the king, and checks given on a
square defended by at least one enemy
pawn or piece apart from the king. The
reason for this is simple: safe checks leave
no other alternative to the king apart from
retreating or, with slider checks, possibly
interposing a defending piece, while
unsafe checks also offer the opportunity to
capture the checking piece. Going to a
square controlled by an enemy piece is
indeed significantly inferior.

230
 safe queen check

Frequency: frequent

Unsafe checks

Value: bonus, specific for the different

checking pieces.

unsafe queen check: 15cps in the mg,

10cps in the eg
unsafe rook check: 15cps in the mg, 10cps
in the eg
unsafe knight check: 20cps in the mg,
10cps in the eg
unsafe bishop check: 8cps in the mg, 6cps unsafe rook check
in the eg
unsafe pawn check: 5cps in the mg, 5cps
in the eg

unsafe pawn check

Frequency: frequent
unsafe knight check

Double checks

Double checks, the case when 2 own

pieces deliver check to the enemy king at
the same time, are very forceful, though a
rare guest on the board. They will
necessarily arise after a discovered
attack/check of a slider upon the enemy
king, with the intermediary own piece
revealing the check also delivering one.

231
Within our evaluation framework, double
checks will not necessitate any special
bonus, for the simple fact that both checks
will add up to reflect the mounting effect. I
do not see any special ad-hoc value over
this addition.

Potential checks

Definition: any possible, but not

delivered, check in a position

Value: small bonus, specific for the

different pieces.

potential queen check: 10cps in the mg, potential queen checks on g5 and c4,
5cps in the eg potential pawn check on f7
potential rook check: 8cps in the mg, 4cps
in the eg Additional information: well, this is still
potential knight check: 15cps in the mg, an important factor and quite tactically
7cps in the eg relevant, as potential check opportunities
potential bishop check: 8cps in the mg, will frequently lead to forced sequences,
2cps in the eg and forced lines are usually detrimental to
potential pawn check: 7cps in the mg, 5cps the potentially-checkable side
in the eg
Frequency: frequent

Potential discovered checks

Definition: a sliding attacker, bishop, rook

or queen, x-ray-attacking the enemy king,
with another own piece between the slider
and the king

Value: bonus, specific for the different

sliders

potential queen discovered checks: 120cps

in the mg, 60cps in the eg
potential rook discovered check: 60cps in
the mg, 30cps in the eg
potential rook check on e1, potential potential bishop discovered check: 30cps
bishop check on b5, potential knight in the mg, 15cps in the eg
checks on f6 and g7

232
potential queen discovered check; Ne7 potential bishop discovered check. One of
possible revealing will be double check, the possible knight moves, Nc7, threatens
too to win the black rook on a8.

potential rook discovered check. The potential discovered checks can also have
bishop on d6 threatens to reveal the own pawns as intermediary objects,
checking rook on b6 in a series of possible revealing the attacker. This time, the e6-e7
moves. discovered check threatens to win whole
queen!

Additional information: potential

discovered checks are considered in our
framework, because it otherwise does not
have standard general bonus for x-ray
attacks upon the enemy king with own
piece as an intermediary object.
Discovered checks are important in their
potentiality, and not in the mere fact of

233
revealing the check, which is a standard well as the piece at the other end of the
check by all means, already provided for. pin, to the opponent side.
With this specific condition, the turn is
very relevant. Basically, there are 2 main types of
important pins: absolute, king pins, and
As easily seen and imaginable on the relative, queen pins. Pins involving other
diagrams posted, almost any discovered pieces at the opposite end of the pin, like a
check is extremely dangerous in its nature, bishop pinner pinning an enemy knight
simply because the piece, revealing the with enemy rook at the far end of the pin,
sliding attacker, will have ample are mostly completely irrelevant and easily
opportunity to attack various enemy seen by the concrete values for direct and
objects. As, apart from the attack of the x-ray attack of the pinner.
revealing piece, the enemy king will also
be checked by the slider, it will have to do King pins
a forced move, or a move for interposition
or capturing of the slider should be made, Definition: a sliding attacker, bishop, rook
thus gaining tempo and giving chance to or queen, x-ray-attacking an enemy king,
the revealing attacker to capture on the with any other enemy piece not directly
very next move. Revealed attacks attacking the slider, or, if doing so, being
involving double checks are even more of higher value than the slider, as an
forceful, as in this case the enemy king intermediary object
will have as its sole option to try evading.
Queen checks are most dangerous in Value: bonus is dispensed in terms of the
nature, similarly to the high queen check different pinning pieces as follows:
values, as, apart from the good checking
property, this might lead to subsequent bishop king pins: 90cps in the mg, 45cps
queen checks, building a mating net, on in the eg
occasion with the support of the revealing rook king pins: 60cps in the mg, 30cps in
piece. the eg
The mg bonus is significantly larger, for queen king pins: 45cps in the mg, 22cps in
the very obvious reason that in the mg the eg
enemy king safety plays bigger role and
there are many more potentially capturable
enemy objects.

Frequency: infrequent

Pins

Pins are an extremely important evaluation

element, closely related to tactics. As a
matter of fact, pins represent a specific
kind of x-ray attacks, involving a single
intermediary object, the pinned piece,
when this object is of lower value than the
other own piece at the other end of the pin.
The pinner, the sliding attacker, pertains to
one side, and both the pinned piece, as a bishop king pin with enemy rook as an
intermediary object, the pinned piece

234
 In some instances, the enemy pinned piece
will also attack the pinner of lower power,
and still enjoy some mobility, but this will
hardly matter, as it will most probably be
lost.

a rook king pin with enemy bishop as an

intermediary object

well, the black queen can still move along

the a8-h1 diagonal, but that does not help a
lot

Frequency: frequent

Queen pins

Definition: a sliding attacker, bishop or

rook, x-ray-attacking enemy queen, with
any enemy piece not attacking the pinner
as an intermediary object.
a queen king pin with enemy knight as an That will exclude enemy bishops for
intermediary object, the pinned piece bishop queen pins, and enemy rooks for
rook queen pins.
As easily seen in all of above examples,
the enemy pinned piece completely lacks Value: bonus, specific for the different
in mobility, and the enemy king must sliders:
make at least a single move, until the pin is
gone, so the probability for the pinned bishop queen pin: 40cps in the mg, 20cps
piece to be lost is very high. That is what in the eg
the nice bonus is actually dispensed for: rook queen pin: 30cps in the mg, 15cps in
good tactical chances to win the pinned the eg
piece, as well as increased further tactical
possibilities due to its temporary zero
mobility.

235
 bishop queen pin rook queen pin, with enemy knight as the
pinned object

As easily recognised from above

examples, although the enemy pinned
piece between the sliding attacker and the
queen enjoys some mobility, this is rather
subjective, as executing a move will reveal
and probably lose the queen. In order to
get rid of the pin, the queen should make
at least a single move, and this takes time.
That is what the bonus is for: restricted
mobility of the pinned piece, with good
chances to win it or gain other relevant
advantages in the tactical scuffle. Of
course, a lot will depend on the side to
move.
In relation to absolute, king pins, queen
another form of bishop queen pin, with pins are a much milder form of pinning,
enemy pawn as the pinned object but still due a significant bonus.

Frequency: frequent

Skewers

Well, skewers are the case of an x-ray

attack, when a sliding attacker of relatively
low value, bishop or rook, directly attacks
an enemy piece and x-ray-attacks another
enemy piece of lower value than the
directly attacked piece. Kings are also
included in the enemy piece of higher
value. For example, one possible

236
constellation is bishop attacking enemy
rook and x-ray-attacking enemy knight,
another one is rook attacking enemy king
and x-ray-attacking enemy queen.
Within our evaluation framework, skewers
will not be dealt with separately, for the
simple reason that they represent a
standard case of x-ray attacks, and all due
bonus points are fully seen by the
respective direct and x-ray attacks of the
sliding attacker, or, alternatively, the
respective checks and x-ray attacks.

Pawn defence

Definition: any non-pawn piece defended the knight on d4 and the bishop on h3 are
by an own pawn under attack, but nothing to fear: they are
well-protected by friendly pawns
Value: bonus, specific for the different
pawn-defended pieces

pawn-defended knight: 15cps in the mg,

10cps in the eg
pawn-defended bishop: 10cps in the mg,
7cps in the eg
pawn-defended rook: 5cps in the mg, 3cps
in the eg
pawn-defended queen: 3cps in the mg,
2cps in the eg

Note: the bonus will be considered

excluding minor piece outposts, as pawn-
defended outposts get their separate value

Additional information: pawn defence is

an extremely important term, as tactically it is good for pieces of higher power to be
very relevant. The bonus is obviously due pawn-defended, too. This saves time in
for 2 reasons: defence and is tactically relevant.
- in case such a piece is under attack by an
enemy piece, it is already protected, so this Additional defence by 2 own pawns is
will save time even better, but difficult to measure
- even if it is not under enemy attack, such numerically for the different pieces with
an attack can come at a later stage, so no specific conditions attached.
defence is ensured preemptively, which
also might matter

Thus, contrary to what some people might

believe, pawn defence is always a good
thing, and to be encouraged.

237
 minor piece defence
minor piece defended by another minor:
15cps in the mg, 10cps in the eg
minor piece defended by rook: 10cps in
the mg, 7cps in the eg
minor piece defended by queen: 7cps in
the mg, 5cps in the eg

rook defence
rook defended by minor piece: 8cps in the
mg, 6cps in the eg
rook defended by queen: 5cps in the mg,
3cps in the eg

queen defence
queen defended by knight: 3cps in the mg,
that white knight seems invulnerable, no 2cps in the eg
matter the number of enemy attackers queen defended by rook: 2cps in the mg,
1cp in the eg
Frequency: very frequent

Piece defence

Defence among pieces is also quite

significant, contrary to what most
available engines would think. There are
few engines out there that would consider
it in their codes, emphasising piece attacks
instead, but it is close to impossible to
separate attacking enemy pieces from their
respective defence. Well-defended pieces
feel well even under strong attack, while
badly defended ones might suffer tactically
even if not immediately attacked.

So, having a good defensive evaluation is the bishop on e1 defends the knight on b4,
a must and more a matter of finding the so the enemy rook attack upon it is not so
right values. dangerous

Definition: any piece apart from the king

and pawns, defended by another own non-
pawn and non-king piece

Value: bonus, validated in terms of the

different defended pieces and the specific
defending ones with the following array:

238
 Defending pawns

Definition: any pawn defended by any

friendly piece apart from the king and
another friendly pawn

Value: small, but well-deserved bonus,

specified in terms of the different
defending pieces

pawn defended by minor piece: 5cps, both

for the mg and eg
pawn defended by rook: 3cps, both for the
mg and eg

Note: the bonus for pawn defended by

the enemy queen attack is not a threat to queen is obviously so small, that it might
the white rook on b6, as it is defended by be better not to consider it at all
the knight on c4. The white queen on h4
also does not have to bother, as another Additional information: some might
friendly knight, the one on g2, sufficiently think defending pawns is not that vital, as
supports it. they represent just a minuscule material,
but that is far from being the case. As
pawns are multiple, and the demise of a
single one of them without compensation
is certainly unwelcome, they should be
protected, whenever possible.

As with other kinds of defence, the bonus

is due for couple main reasons:
- tactically relevant
- pawns under enemy attack are safe
- even if not under immediate attack, a
similar possible attack in the future will
only save time

The numbers for the mg and eg are equal,

as it is difficult to make a real distinction.
It is true that attacks, and consequently
the white rook on e4 supports both the respective defences, are more important in
white bishop on b4 and the white knight the mg, but, on the other hand, in the eg
on f4, so the enemy challenge is quite many defended pawns will be passers,
bearable which further boosts their value.

Frequency: very frequent

239
 Minor piece defending passed pawn

Definition: passed pawn, on its 5th, 6th or

7th ranks, defended by a minor

the white pawns on a5 and g7 are safe,

although under attack by the black rook
and king, as defended by the friendly
bishop on c3.
It is meaningless to consider the knight
defence of the h5 pawn, as it is already the knight on d3 defends the c5 passed
very-well protected by the friendly pawn pawn, the bishop on f4 that on h6
on g4.
Value: bonus, 12cps, both for the mg and
eg

Additional information: the bonus is due,

because an advanced passed pawn is a
valuable asset, and supporting one's
valuable assets is always productive.

Even if not currently attacked, they might

soon be so.

Note: protected passed pawns might be

excluded from the bonus, as they already
enjoy the support of an own pawn

Frequency: frequent

rook protecting the undefended pawns on

a3 and g3 is a vital feature, both in the mg Central isolated pawn, defended by
and eg minor

Frequency: very frequent Definition: central d4 or e4 isolated pawn,

defended by a minor piece, knight or
bishop

240
 by the knight on f3, making the pawn
invulnerable.

A bishop instead of a knight will often also

do fine.

Frequency: very frequent

Undefended pieces

Definition: knight, bishop or rook, not

defended by any own pawn or piece,
including the king

Value: bonus, specific for the different

d4 is such a pawn undefended pieces

Value: bonus, 8cps, both for the mg and undefended minor piece(knight or bishop):
eg 15cps in the mg, 10cps in the eg
undefended rook: 10cps in the mg, 7cps in
Additional information: the bonus is due the eg
for the obvious fact, that this is not just a
random undefended pawn, but a very Additional information: the bonus is due
important one, under frequent enemy for the obvious reason that such pieces are
attacks, so protecting it is extremely vulnerable, tactically weak, and can fall
useful. Minor pieces, of course, will do prey to enemy attacks, especially queen
that best. forks, either immediately, or in a longer
forced series of moves.
Thus, it makes sense scoring them, even if
there is not a currently available threat.
The mg bonus is a bit larger, as in the mg
tactics and forks are much more frequent.

some humans/engines might think that

white has much worse, due to its isolated
central pawn, but, in actual fact, the
position is completely equal. The reason
for that is the excellent support, provided

241
white has 2 undefended pieces: the bishop Rook on a semi-open file, attacking an
on d3, and the rook on a2. Currently, enemy pawn-undefended pawn,
nothing is visible that might make those defended by a minor
pieces suffer, but, with the development of
the game, a similar condition might be
tactically relevant at any time.
For black, just the knight on h5 is
undefended, but, if white is to play, Ne5,
combining threats on the enemy queen and
knight, already wins the knight.

the rook on a8 gets the penalty. It is on the

semi-open a file, and attacks the white a4
pawn, which is not defended by another
pawn, but supported by the bishop on d1.

Value: small penalty, -5cps in the mg, -

2cps in the eg
in the eg, undefended pieces are also an
undisputed liability, especially vulnerable Additional information: the penalty is
to enemy queen checks and forks. Possible due for 2 main reasons:
Qg4 above threatens to win either the - waste of resources; the strong rook is
white rook or knight, actually, with the attacking a weak enemy pawn, that is still
specific board condition, both of them. invulnerable
- inability of the rook to easily penetrate
Frequency: frequent along the semi-open file

Obviously, this is not quite the place for

the rook.

242
black might think it has achieved a lot by bonus goes for the aligned d3 pawn. d3-d4
piling up pressure along the semi-open a is a safe pawn push threat upon the black
file, getting sufficient counterplay, with bishop.
the weak a3 pawn under heavy attack by
both black rooks, but in actual fact, black
does nothing. The a file is logically closed,
black should sacrifice the exchange in
order to penetrate, so both black rooks are
only wasting their time on the queen side.
Of course, white has substantial advantage.

Similar simulations of positional factors,

like closed files, are often completely
missed by engines.

Frequency: frequent

Threats

bonus goes for the c2 defending pawn. c2-

Safe pawn push threat c4 is a safe pawn push threat upon the
black queen.
Definition: aligned pawn, with the square
in front of it free, and any enemy piece Value: bonus, 15cps, both for the mg and
apart from pawn and king positioned 2 eg
ranks higher on adjacent file.
Only in the case of pawns on the 2nd rank, Additional information: the bonus is
defending pawn, with the squares on the very-well due for the following reasons:
3rd and 4th ranks in front of it free, and - there is a potential pawn threat upon an
any enemy piece apart from pawn and king enemy piece
positioned on the 5th rank on adjacent file. - the threat is tactically relevant

243
- if executed, the enemy piece will most bonus goes for the b5 pawn that is not
likely have to retreat, which gains a aligned. b5-b6 is an unsafe pawn push
valuable tempo threat upon the black knight.
- the pawn threat is pretty much
guaranteed to succeed, as the square where
the pawn will land is defended by another
own pawn, either a duo, or a defended one,
when the push-threatening pawn is on its
2nd rank

It is difficult to make a distinction between

mg and eg values, as, while in the mg
gaining tempos and threats might be
relatively more important, in the eg on the
other hand, such pawn push threats
frequently represent important passed
pawn advances.

Frequency: very frequent

bonus goes for the g2 pawn that is not

Unsafe pawn push threat defending. g2-g4 is an unsafe pawn push
threat upon the black rook.
Definition: pawn, that is not aligned, with
the square in front of it free, and any Value: bonus, 8cps, both for the mg and
enemy piece apart from pawn or king eg
positioned 2 ranks higher on adjacent file.
Only in the case of pawns on the 2nd rank, Additional information: the bonus is due
not defending pawn, with the squares in for the very same reasons as in the case of
front of it on the 3rd and 4th ranks free, a safe pawn push threat:
and any enemy piece apart from pawn or - threat is tactically relevant
king positioned on the 5th rank on adjacent - if executed, the attacked piece will likely
file. have to retreat, which gains precious
tempo

In distinction to safe pushes, however, the

certainty the push will be successful is
much smaller, all will depend on the
particular friendly and enemy piece and
pawn control of the square where the pawn
will land, hence the lower values.

Frequency: very frequent

Tactical levers

Definition: lever pawn, with enemy piece

on the rank behind the enemy lever pawn
on adjacent file

244
 usually gain tempos, this might certainly
change the course of the game in a range
of occasions, so it undoubtedly represents
an asset to be counted with.

Frequency: frequent

Tactical pawn threat

Definition: pawn, attacking an enemy

piece, with another enemy piece on the
rank behind it on adjacent file

d4 is a tactical lever for white. It is

levering the black e5 pawn, and, on the
rank behind the e5 pawn on adjacent file
there is an enemy piece, the d6 knight.

b5 is such a pawn. The knight on c6 is

attacked, but, apart from that, upon
capturing it, the pawn will already attack
another enemy piece, the rook on d7.

b3 is another tactical lever for white, this

time, the enemy piece behind the enemy
c4 lever pawn is a rook

Value: bonus, 11cps in the mg, 9cps in the

eg

Additional information: the bonus is due

for the obvious tactical ability of such
lever pawns. While both pawns are levers
and able to capture, the tactical lever has
the additional advantage of attacking an
enemy piece upon capturing. As threats

245
b2 is another such pawn. It attacks the the e4 pawn, together with the knight on
black bishop on c3, and, on the rank d6 and the pawn on f6 represents this
behind the bishop on adjacent file, there is condition
another enemy piece, the black queen on
b4.

Value: bonus, 20cps in the mg, 15cps in

the eg

Additional information: the very-well

deserved bonus is obviously for the fact,
that such a pawn in combination with the
enemy piece configuration is very much
tactically relevant. In both instances, upon
capturing the enemy piece, the pawn
already attacks a second enemy piece. This
will certainly be able to gain tempos on
many occasions. And gaining tempos, of
course, will help in attaining other
positional advantages, if not immediately
winning material. one more such condition, this time one
rank higher
Frequency: infrequent
Value: bonus, 12cps in the mg, 6cps in the
eg, for the side with the pawn on the 4th or
Tactical lever threat 5th ranks

Definition: pawn on the 4th or 5th ranks, Additional information: the advanced
with the square in front of it free, one pawn is, of course, very much tactically
enemy pawn 2 ranks higher on one dangerous.
adjacent file, and another enemy piece 2 The bonus is given for the following
ranks higher on another adjacent file reasons:
- when the pawn moves forward, it will
simultaneously attack 2 enemy objects,
and, if not captured, will be able to take
one of them
- even if the enemy pawn captures it,
another own piece can land on the capture
square, on an advanced position
- in case the pawn is pushed, and the
enemy pawn passes in capturing, under
certain conditions, it can advance even
further on the very next move

Such advanced pawns are especially

dangerous, when central or on the side,
where the enemy king is, in the mg. In this
case, they might greatly benefit opening
lines in the center or, alternatively,
breaking open the enemy king shelter.

246
 immediate destruction of the black pawn
shelter.

Frequency: frequent

Knight attack threat upon enemy queen

Definition: knight, attacking a square,

from where it will attack the enemy queen,
provided that the square is free and not
under attack by an enemy pawn

the white pawn on e4 constitutes a tactical

lever threat. Upon moving forward one
square, on e5, it will simultaneously attack
the black knight on f6 and the black pawn
on d6. At the same time, on e5, the pawn
already builds another tactical lever threat,
aiming at the d7 knight and the pawn on
f7. As the e5 push will forcefully evict the
black knight on f6, gaining tempo, the
pawn will be able to execute another pawn
push on the very next move, e5-e6, helping
to open lines in the center for attack.

the knight on b2 has an attack threat upon

the enemy queen, as upon landing on the
c4 square, that is free, and not under attack
by an enemy pawn, it will start attacking
the queen.
The black knight on f8, on the other hand,
although attacking a square, from where it
will threaten the white queen, g6, does not
get the bonus, as the g6 square is under
control of the white pawn on f5.

Value: small bonus, 8cps in the mg, 5cps

in the eg

Additional information: this feature is

similar to the pawn push threat, but less
tactical lever threats are even more salient.
dangerous, when existing on squares close The bonus is given for the possibility to
to the enemy king shelter. gain tempo by threatening the queen, that
g5 tactical lever threat above is extremely will almost certainly have to retreat
dangerous, with g5-g6 threatening an

247
somewhere, with tempos playing an
important role, especially in the mg.
This is a much more compelling condition
than for example, a bishop or rook
threatening to attack the enemy queen on
the next move, as, in distinction to those
attacks, knight attacks can not be avoided
by interposition of a piece.

the white rook on d1 takes the open d file

Value: bonus, 40cps in the mg, 25cps in

the eg

Additional information: this is a very

weighty term, no chess handbook will ever
miss to mention. The rook on open file
prevents enemy pieces from taking active
in the Scandinavian Defence, after 1.e4 d5 positions along that file and threatens to
2.ed5 Qd5, the black queen falls under the penetrate all the time deep into the enemy
potential attack of the white knight on b1 camp.
from the c3 square very early into the On the diagrammed position, with
opening. everything else being equal, the single
That gives white tempos for development, placement of the white rook on an open
and that is why the Scandinavian is not a file decides the game. After Rd1-d7,
good opening to start with. penetrating on the 7th rank, white will win.

Frequency: very frequent Frequency: very frequent

Rook on open file Queen on an open file

Definition: rook, with no own and enemy Definition: queen, with no own or enemy
pawns on the file, where it is pawns on the file where it is

248
well, this time, apart from the rook, the the black rook on b8 is placed on the semi-
white queen on d3 is also placed on an open b file. Although the black pawn
open file. Qd3-d7 will similarly decide the structure is severely compromised, the pair
game. of doubled isolated pawns on the a file is
more than compensated for by the strong
Value: small bonus, 10cps in the mg, 5cps influence of the black rook,
in the eg simultaneously attacking the b2 pawn.
Black enjoys the advantage.
Additional information: this term is far
less weightier than rook on an open file, Value: bonus, 25cps in the mg, 10cps in
one of the reasons being that it is the eg
frequently much less durable, with queen
easily oustable from the file by an enemy Additional information: another weighty
rook landing there term. Any evaluation lacking it is simply
incomplete and weak. The rook will
Note: it does not really make sense to frequently attack different enemy objects,
consider queen plus rook on an open file pawns or pieces, along the semi-open file,
as a separate feature, as, as easily seen on with penetration, deep into the enemy
the diagrammed position, the 2 separate camp, also being possible, like, for
bonuses add to one another in self- example, Rb8-b3 thrust on the
elevating the term diagrammed position. At the very least, the
possession of a semi-open file will mean
Frequency: frequent the opponent is on the defence.

Frequency: frequent
Rook on a semi-open file

Definition: rook, with at least one enemy Queen on a semi-open file

and no own pawns on the file, where it is
Definition: queen, with at least one enemy
pawn and no own pawns on the file, where
it is

249
apart from the rook, this time also the the white rook on c7 enjoys the privilege
black queen on b6 takes up the semi-open of occupying the 7th rank
b file, ratcheting up pressure
Value: bonus, with average value of 40cps
Value: small bonus, 7cps in the mg, 3cps in the mg, 25cps in the eg
in the eg
Note: within our framework, this is seen
Additional information: this is a by the rook psqt
significantly less important term than rook
on a semi-open file, but entirely failing to Additional information: well, an
consider it would be wrong. As seen on the extremely weighty term no handbook will
diagrammed position, the pressure from ever fail to pay attention to. Assets are
the black queen, though real, is somewhat obvious. On the diagrammed position, the
degraded by the ability of the d2 white c7 rook:
rook to effortlessly defend the b2 pawn, - has penetrated deep into the enemy camp
even without the support of the white - directly attacks the black b7 and g7
queen. The term also supposes possible pawns
penetration into the enemy camp, as with - x-ray-attacks the a7 and h7 pawns
the rook. - attacks the black king shelter
- restricts the black king to the 8th rank
Frequency: frequent
What else is needed for a term to be
influential?
Rook on the 7th rank
Frequency: frequent
Definition: rook on any square on the 7th
rank

250
 Queen on the 7th rank Doubled rook file control

Definition: 2 rooks, defending each other

on the same file, even if this file is not an
open one

Value: bonus, 15cps, only for the mg

Additional information: this feature is

always useful, and equally so in all
possible constellations. In case the rooks
take an open file, their cumulative value
will be more than double the value of a
single rook on an open file, for the simple
reason that it will be very difficult to
challenge the file upon which the rooks are
placed, unless by an enemy minor,
defended by a pawn. Penetration by the
well, similarly, queen on the 7th rank, as rooks will also be easier, as the more
c7 is, does deserve some bonus advanced rook is already supported.

Value: much smaller than for the rook,

however, this might be seen in terms of
non-redundancy by terms like attack upon
enemy pawns and pieces and attack of the
enemy king shelter. It is also possible to
bonise the queen in psqt.

Additional information: the bonus is

obviously due for the very active,
attacking position of the queen. On the
diagrammed position, the white queen:
- attacks the white rook on b8
- attacks the black king shelter
- attacks the b7 and g7 pawns
- x-ray-attacks other relevant objects and
squares
with everything else being more or less
Frequency: frequent equal, white enjoys decisive advantage,
due to the overwhelming control upon the
open d file by the self-defended pair of
Doubled rooks on the 7th rank rooks. No enemy piece can easily take a
place upon that file, the fight for the file
Note: within our evaluation framework, itself is very dreary-looking, for example,
this is not considered, as will be more or playing immediately Ra8-d8 to attempt
less tantamount to adding up the numbers wresting out control is simply impossible,
for the 2 separate rooks. I can't see no and not very easy to do, if at all, in the
distinction at all. longer term, and if so, will take some time,
and white even threatens to successfully
sac one rook on d7, gaining superior

251
position on the 7th rank, with a lot of - Ba6 pseudo-sac would not be quite
threats. feasible
In case the rooks were not doubled, most - black would be able to successfully
of the above would be not doable, for choose the freeing b7-b6 move
example, with just a single white rook - lining the queen along the b file to
upon the d open file, the Ra8-d8 challenge support a single rook in its assault would
by black would be feasible immediately, not really represent a major danger, and
and the bold Rd7 sally on the 7th rank just even the black position would not look that
a dream. much defensive, too

Placed on a semi-open file, the rooks Finally, the pair of self-defending rooks
represent quite an asset, too. are an excellent feature, even if only on a
closed file. Who would have thought so?
Outwardly, there is nothing to do for the
rooks on such a file. But, in reality, the
truth is quite the opposite, for:
- the rooks still do defend each other,
which on occasion matters
- most importantly, the pair constellation is
fit and ready for all of its feats, in case the
currently closed file do gets opened, or at
least transforms into a semi-open one. As
in chess things sometimes change very
quickly, and opening a file is frequently
quite realistic under many circumstances,
having a battery ready to attack is always
welcome.

the pair of self-defended white rooks along

the semi-open b file are a major asset:
- white threatens with Ba6 to immediately
restore the material balance
- a freeing move like b7-b6 is impossible
to play, because of the sufficient over-
control of the file, more specifically the b6
square
- on occasion, if necessary, white can
further increase the pressure along the b
file and the black b7 pawn, by switching
the queen to b2, or, alternatively, by
playing Rb1-b2, followed by Qb1
- very importantly, too, black is all the
time on the defence, which really does
matter currently, black is able to rather
successfully defend the vital e5 square. If,
In case just a single white rook was taking however, at some point it is compelled to
the semi-open b file, most of the above relinquish control of that square, under
would be impossible: specific tactical circumstances, after, for
example, e5-f4 g3-f4, white immediately

252
threatens with an e4-e5 central break, to the doubled white rooks and queen along
follow up a bit, after e4-e5 f6-e5 f4-e5 d6- the open c file, with the queen in between
e5 Nf3-e5 Nd7-e5 Nd3-e5 Bg7-e5 Re2-e5, both rooks, represent a tremendous asset
the rooks have already taken up the open e
file to great effect. And this mostly Value: bonus, 40cps, just for the mg
happened in a split-second action, after a
forced line. Additional information: the bonus is
Besides, the current placement of the rooks obviously due for the unchallenged control
on different ranks, by definition, does upon the open file.
allow them to form the very same self- On the diagrammed position, white is so
defending constellation on an alternative firmly in control of the open c file, that
file rather quickly, if necessary. For seemingly nothing can wrest it out, even in
example, on the diagrammed position, the longer term.
white can play Rf2 and Re1-f1, doubling Of course, all of the heavy pieces would
the rooks along the f file, in just 2 moves, get a separate bonus for taking the open
the similar manoeuvre, Rd2, followed by file, but that is an over-bonus for the
Re1-d1, is possible within the same time specific arrangement with the queen
limits, in case the rooks had not been between both rooks, highlighting
doubled, usually that would have taken preponderance.
significantly more time. Other possible constellations of the 3
pieces along the same open file would not
Thus, a pair of self-defended rooks is a be quite so good, for objective reasons. If
very positive feature on any file. the queen was first, on most advanced
rank, that would signify a probable
Frequency: frequent challenge by an enemy rook along the
open file, it would be sufficient for the
rook to be supported by any minor piece,
Royal battery or even by another rook. And in case the
queen was last in the arrangement, on least
Definition: pair of rooks and queen on an advanced rank going behind both rooks,
open file, in the order rook-queen-rook, in that would on many occasions be
terms of more advanced ranks tantamount to the inability of effective
penetration, as the rooks are a bit clumsy
in this specific order. Frequently, for a
successful outcome of the assault, you
need the queen to switch from the open
file to alternative advanced squares and
back, and that would not be feasible with
the queen so miserably placed on a back
rank.

Frequency: infrequent

253
 Continuous rook control Above-posted diagram represents a
continuous rook control upon 2 adjacent,
Definition: 2 rooks on the 1st rank next to currently closed, files, but of course, the
each other rooks will only feel quite happy on any
other possible combination of file
placement, for example on 2 open files,
one open and one semi-open file, or one
open and one closed file.

the white rooks on f1 and g1 represent

continuous rook control upon the f and g
files

Value: bonus, 15cps, just for the mg mainly thanks to both white rooks on the
semi-open d and e files, and the
Additional information: the bonus is due continuous rook control in the center,
for the fact that such rooks would wield a white exercises a significant pressure, so
significant direct and x-ray control upon a much so, that it is better even without a
series of continuous squares along both pawn
adjacent files where they are situated.
Continuity in control/attack means, that Frequency: frequent
there will be no loose ends, no weak points
in the attack/pressure along those files.
For example, on the diagram, white has a Rook on the same file as enemy queen
devastating position after f2-f4, and one of
the reasons for this is the excellent Definition: rook placed on the same file as
placement of both white rooks on adjacent enemy queen, no matter if the file is
files. In this way, different pushes, like f4- closed, open, otherwise, or the number of
f5, g3-g4-g5 are easily possible, with black own and enemy objects, pawns and pieces,
threatened by opening the king side all the between the rook and queen
time, enemy pieces will have hard time
finding postings along the continuous files,
and the attack overall will be much more
compelling, with the rooks supporting
possible activity of other own pieces
focusing on the king side and the above-
mentioned 2 files all the time.

254
 Value: bonus, 18cps in the mg, 7cps in the
eg

Additional information: this is a very

welcome constellation, indeed. The very-
well deserved bonus is due because:
- both pieces simultaneously defend each
other
- the configuration ensures thorough
control over the diagonal where both
pieces are placed. Any enemy piece or
pawn will have hard time landing there.
This is especially vital in case the battery
occupies some important diagonal of
bigger square length, emphatically more so
if this is one of the 2 longest board
the white rook on b1 is placed on the same diagonals, a1-h8 or h1-a8. Apart from not
file as the black queen on b8, and this allowing enemy pieces to land there, the
bodes nothing well for the queen, as well tandem also represents an important form
as the overall game development of square control, on occasion targeting the
enemy king shelter, too.
Value: bonus, 15cps, just for the mg - in the very specific case of queen
attacking a square of the enemy king
Additional information: the bonus is due shelter, also attacked by the enemy king,
for 2 main reasons: and the bishop x-ray-attacking it, this turns
- this will help the rook side with gaining into a major attacking formation,
positional advantages due to inherent threatening quite unpleasant check, and
tactical considerations because of the sometimes even mate, with great
queen-rook opposition efficiency attached to it
- on occasions, the queen might also fall
prey to elaborate tactics, because of the
very same opposition motif

For example, on the diagrammed position,

white can advantageously open the
position on the queen side, after a5, Nc5
and b5, unleashing the b1 white rook. In
case the black queen lingers a bit longer on
the b file, it might very well also suffer.
Please note, that the opposition is
effective, even though there are 4 own and
enemy objects between the queen and
rook, 2 pawns and 2 minor pieces.

Frequency: frequent

queen and bishop defend each other with

Queen and bishop battery little effort. Qc6-c1 is answered by Be3-
c1, while Re8-e3, in a real-life situation,
Definition: bishop attacking own queen could be answered by Qc1-e3, no need to

255
lose tempos on ensuring pieces are
supported.

even though both white attacking pieces

are very distantly placed from the enemy
king shelter, they do represent a
the black queen + bishop battery along the tremendous attacking asset. Qd3-h7 check,
a8-h1 diagonal is extremely powerful. The and a possible mate, depending on real-life
enemy king shelter is taken aim at, but, circumstances, is a mighty threat, and the
apart from that, and most importantly, no check is feasible, because the batteried
white piece can even think of touching that white bishop will support on an x-ray the
diagonal. Ne4 would lose a pawn, Nf3 is checking queen.
impossible, Bg2 is impossible too. If only Thus, the tandem guarantees big danger to
a single black piece occupied the long the enemy king, despite its remoteness.
diagonal instead, all of the above- This will allow great efficiency in
mentioned moves would not lose material. combining functions and enhanced tactical
Thus, the prevalence of control upon a relevance in the form of forking enemy
specific diagonal is what severely limits pieces and the king shelter.
opponent choices of piece placements,
yielding quite a nice positional plus. Overall, the term is extremely useful and
This feature is very similar to a queen + multi-functional.
rook battery on an open file.
Frequency: frequent

Minor outpost stopping enemy rook on

an open file

Definition: minor outpost on its 4th, 5th or

6th rank, supported by a pawn, with an
enemy rook on the same open file on more
advanced square(from the point of view of
the minor) attacking it

256
the outposted white bishop on c6, this is a big plus in the mg. While both
supported by the friendly b5 pawn, stops black rooks on their respective b and d
the enemy rook on the open c file open files are stopped from penetrating by
the white outposted minors on b5 and d4,
Value: bonus, 20cps in the mg, 10cps in strongly supported by pawns, the white
the eg rook on the open h file is very active and
pretty much unchallenged, with another
Additional information: the bonus is white rook and the queen able to soon join
given for the obvious ability of such an it.
outposted minor to prevent enemy rook
penetration deep into the own camp along
the open file.

On the diagrammed position, the most the

black rook can do on the open c file is
budge to c7, in case the white bishop was
not there, it could have penetrated on c3,c2
or c1.
Of course, the minor is able to do this,
because it is defended and strong.

in the eg, the bonus is also due, but less

important, as with lower number of pieces
in the eg, there are usually sufficient
alternative penetration thoroughfares

Frequency: frequent

257
 Minor piece attacking a square on the On the other hand, both white rooks can
8th rank on an open file, simultaneously immediately and without hindrance
attacked by an enemy rook occupy the open file via the c1 square.

Definition: minor piece, knight or bishop,

attacking a square on the 8th rank, that is
empty, part of an open file, and
simultaneously attacked by an enemy rook
on the same 8th rank(its relative 1st rank)

Value: nice bonus, 15cps, just for the mg

Additional information: the bonus is

dispensed for the obvious reason, that the
minor piece will cut access of the enemy
rook to the open file.
This is important, as the penalised side
will not be able to quickly take the open
file, a significant positional asset, which
will allow the opponent to make use of
that fact and mobilise one or 2 heavy this time, although not outposted and from
pieces there. At the very least, this gains afar, the black bishop on h6 does the very
some tempos to start developing a more same with the c1 square, currently
serious initiative. inaccessible for both white rooks.
The bonus is mg-only, as in the eg space White should try to get rid of that
advantage, closely related to the term, is unpleasant condition, by playing Bb2-c1,
far less important, and besides, in the eg or, alternatively, interposing a piece along
there are usually more thoroughfares rooks the bishop ray of action, possible after
can utilise to gain freedom. Na3-c2-e3, for example.

Frequency: infrequent

Minor piece attacking a square on the

1st or 2nd ranks on an open file,
simultaneously attacked by an enemy
rook

Definition: minor piece, knight or bishop,

attacking a square on the 1st or 2nd ranks
on an open file, simultaneously attacked
by an enemy rook on that very same file

Value: small bonus, 8cps, just for the mg

Additional information: the bonus is

the white outposted knight cuts the access given for the obvious fact, that such minor,
to the c8 square on the open c file of the by defending that square, will prevent
black rook on b8. penetration of the enemy rook on its
relative 7th or 8th rank.

258
The bonus is just mg, as in the eg, with the
significantly smaller number of pieces,
space advantage loses in importance, and
with it, possible penetration.

the rook on a1 supports the a6 passer from

behind

Value: bonus, 7cps in the mg, 10cps in the

eg
the white knight on f1 prevents possible
penetration of the black rook on d6 on d2, Additional information: the bonus is
a square on the 7th rank for the black rook, given for 3 main reasons:
the white bishop on f3 does the very same - the rook defends the pawn
with the d1 square. - the rook will support its advance
Apart from that, the white bishop might forward, if the pawn is free
help in wresting control of the d line out of - in all cases, as the pawn will be very
black's hands. much advanced, rank 5 and higher, the
rook itself is guaranteed to enjoy good
Frequency: frequent mobility along the file

The condition the pawn should be placed

Rook supporting a friendly pawn from on higher ranks is relevant, because
behind otherwise the rook would not enjoy
sufficient mobility and the pawn could
Definition: rook attacking an own pawn easily be blocked close to home, making it
on the same file, with the pawn placed on more vulnerable than an asset.
rank 5 and above
Of course, passed pawns will gain in force,
when supported in this way, as their
advance is even more important, but the
supporting rook could defend as well any
other pawn.

259
 f3 is another such pawn. It attacks the e4
and g4 squares, that are both free and
simultaneously attacked by the black
knight on f6.

Value: small bonus, 5cps, just for the mg

Additional information: the bonus is

given for the obvious function of such a
pawn of cutting access of enemy minor
pieces to the 4th rank, where they already
penetrate into the opponent half of the
board, becoming quite dangerous.

One might think this is a stupid rule, but,

in actual fact, it is difficult to overestimate
rook supporting the c5 white pawn from its importance. The rule is so frequent, and
behind. This might help with levering on penetration of enemy minor pieces on the
c6 and opening lines for attack. 5th rank in the mg is so counter-
productive, that such configurations should
Frequency: frequent be created whenever possible. This could
completely change whole systems of play.

Preventing enemy minor penetration

Definition: pawn on the 3rd rank,

attacking an empty square, also attacked
by an enemy minor piece

white has substantial development

advantage, but, as a matter of fact, only
black could be better. Reason? The already
developed white minor pieces have no
penetration points, so the development
lead is pretty much nullified. The h6 pawn
a3 is such a pawn. It attacks the b4 square controls the g5 square, where neither the
on the 4th rank, that is free, and bishop on f4, nor the knight on f3 can land.
simultaneously attacked by the enemy The a6 pawn controls the b5 square, where
bishop on e7. neither the knight on c3 can land, nor the
bishop on f1 deliver tempo-gaining check.

260
On the other hand, black already threatens
with a very nasty pin, after Bg4. That is
why h2-h3 for white could have been
extremely useful.
Such small details sometimes change the
whole game!

Frequency: very frequent

Stopping bishops on long diagonals

Definition: bishop on a long diagonal,

with 2 enemy pawns on the same diagonal,
with one of them defending the other.
Specifically, with white bishop on the h1-
a8 long diagonal, black pawns would be there is certainly big distinction between
found on the e4 and d5, d5 and c6, or c6 the power of the white g2 bishop and that
and b7 squares; with white bishop on the of the white b2 bishop. The white g2
a1-h8 diagonal, black pawns would take bishop develops a tremendous activity
the d4 and e5, e5 and f6, or f6 and g7 along the h1-a8 diagonal, with almost all
squares. possible x-ray attacks completely tactically
relevant, while his queenside counterpart
Value: -12cps, only for the mg is fully reined in by the mighty wall of the
e5-f6-g7 black pawns, facing it.
Additional information: the penalty is
due, simply because this is the best enemy The term would be relevant for both
pawn configuration at trying to severely kingside and queenside fianchettos.
restrict the activity of the bishop along the
diagonal. With pawns placed like that, the Theoretically, the feature no doubt
otherwise extremely efficient bishop x-ray deserves great attention, as a very wide
attacks upon enemy objects on the range of openings could be treated like
diagonal are almost completely nullified. that. It is not rare that even top humans
The long-range bishop power faces the will on occasion underestimate its
wall of the enemy pawn construction and relevance, while, even the top programs,
mostly stops there. are mostly completely unaware of it.

The relevant construction should be

chosen very early in the game, otherwise it
might already be too late.

Frequency: frequent

Raking bishops

Definition: pair of bishops on adjacent

squares on the same file or rank, provided
one of them is on a long diagonal, or a
diagonal at least 7 squares long

261
Bg2 and Bf2 are raking bishops. They are the bishops on b2 and c2 are a tremendous
on the same rank next to each other, and asset
one of them is on a long diagonal, Bg2.
Black Be7 and Bd7, on the other hand, Frequency: infrequent
although on adjacent squares on the same
rank, are not raking bishops, as none of
them is on a diagonal at least 7 squares King restricted on an edge line
long.
Definition: king on edge a or h file, with
Value: bonus, 10cps in the mg, 5cps in the enemy rook on adjacent file, or king on
eg edge 1st or 8th rank, with enemy rook on
adjacent rank, with the rook attacking all 3
Additional information: the bonus is squares the king also attacks(just 2, if the
given for the continuous control of squares king is in a corner), that are empty
along both diagonals of bigger length,
where the bishops are placed.
Continuous control of squares means
enemy objects, whether pieces or pawns,
will have hard time landing in the whole
portion of the board, under attack by the
bishops.
As easily seen on the diagrammed
position, the pair of white bishops control
the adjacent e4,d4,d5 and c5 squares,
where enemy pieces will have difficulty
appearing.

Such bishops are especially dangerous

when attacking the enemy king shelter.

the white king is on the edge 1st rank. The

black rook attacks all 3 squares the king

262
also attacks, f2,g2 and h2, that are all
empty.

Value: penalty, -15cps, both in the mg and

eg, for the king

Additional information: the penalty is

given for the obvious restricted state of the
king.
It is due for the following reasons:
- in the mg, the restricted state might lead
to mating situations, involving 2 enemy
heavy pieces
- in the eg, such a king will be very much
inactive, unable to join in the fight, at least
for the time the restriction is perpetuated
white has excellent winning chances,
precisely because of the extremely inactive
black king, due to its restriction on the
edge 8th rank.
If the black king was more active,
somewhere in the center, the game could
certainly have ended with a draw.

Frequency: frequent

Pawn support for rook on an open file

Definition: rook on an open file, attacking

a square, simultaneously attacked by an
own pawn, and not under attack by an
enemy pawn
although a rook and a piece down, with its
turn to move, white quickly mates the
black king, precisely because of its
restricted condition on the edge h file

263
Rb1 is such a rook. It is on the open b file,
and attacks the b6 and b3 squares,
simultaneously attacked by the own pawns
on a5 and a2 respectively. Its black
counterpart on b8, on the other hand, is not
such a rook, as the only square black
pawns attack on the open file, b5, is under
attack by the white pawn on c4.

Value: small bonus, 5cps in the mg, 2cps

in the eg

Additional information: the bonus is due

for the simple reason that such condition is
very helpful in fighting for the open file.
The squares simultaneously attacked by
the rook and the own pawn are frequently because of the white queen controlling the
excellent outpost squares, the rook can use e4 square, the white e pawn can go there.
them to penetrate into the enemy camp or, Otherwise, this would have been
alternatively, to straighten the friendly impossible.
pawn structure.
Frequency: frequent
Frequency: frequent

X-ray square control

Queen controlling the center
X-ray square control will refer to diagonal
Definition: queen attacking one of the 4 sliding pieces x-ray-attacking different
central-most board squares, e4,d4,e5 or d5 board squares, with an own pawn between
the attacker and the attacked square.
Value: minuscule bonus, 3cps, just for the
mg
Bishop x-ray-attacking the center
Additional information: such condition is
useful in 2 ways: Definition: bishop x-ray-attacking one of
- the queen can quickly transfer to a center the 4 central-most board squares, e4,d4,e5
square, and queens feel well on central or d5, with an own pawn between the
squares, unless immediately threatened bishop and the attacked square
- the queen can support on such square
another own piece taking central position, Value: bonus, 8cps for the mg, 4cps for
and especially pawn the eg

Additional information: the bonus is due,

as this helps in controlling the center.

264
the bishop on c2, x-ray-attacking the e4 This feature can have a big imprint on a
square, with the own d3 pawn between the range of opening systems.
bishop and the attacked square, stops the White can not push the freeing central d3-
black e5 pawn from further advancing to d4 break, because the black bishop on g7,
e4 x-ray-controlling the d4 square, provides
one more valuable, as well as the decisive
attack upon this square. In case the black
bishop did not control that point, white
would have played the mentioned break to
great effect.
Sometimes, such small details decide the
outcome of the fight.

Frequency: frequent

Queen x-ray-attacking the center

Definition: queen x-ray-attacking one of

the 4 central-most board squares, e4,d4,e5
or d5, with an own pawn between the
queen and the attacked square
controlling similar squares on the 5th rank
is even more important, as this prevents Value: small bonus, 3cps, just for the mg
enemy pawns from even reaching the
middle of the board, making them Additional information: the bonus is
backward. given for the further boost the queen
As such pawns would be central, the provides in this way to central control.
influence upon the whole game, especially
in the mg, will be significant.

265
the black queen on c7 x-ray-attacking the the bishop on e3 x-ray-controlling the b6
vital central e5 square allows black to square in front of the black b7 backward
immediately push e7-e5, with the black pawn, with the own c5 backwardmaker
pawn taking advantageous central position. pawn on the ray between the bishop and
In case the queen had not been doing that, the b6 square, highlights the backwardness
the e7-e5 thrust might have been tactically of the b7 pawn.
impossible, and in some cases white might In case the bishop was not attacking the b6
have pushed e4-e5 instead. square on an x-ray, with the support of the
black knight on d7, black might have
Frequency: frequent gotten rid of the backward pawn after the
b7-b6 push.

Bishop x-ray-attacking the square in

front of enemy backward pawn

Definition: bishop x-ray-attacking the

square in front of enemy backward pawn,
with the own backwardmaker between the
bishop and the attacked square

Value: bonus, 6cps, both for the mg and

eg

Additional information: the bonus is due

for the obvious restricting influence upon
the enemy backward pawn.
In a way, this makes it even more
backward, sometimes even permanently
backward, depending on circumstances. with opposite colour bishops, such feature
might make the enemy pawn permanently
backward, as b7 is above, because friendly
pieces capable of supporting a freeing
push might be lacking

266
Frequency: frequent Staying with a backward shelter pawn with
this condition is also not an option, as this
will give the opponent sufficient time to
Bishop x-ray-attacking the square in regroup pieces and start a powerful attack.
front of enemy shelter backward pawn
Frequency: infrequent
Definition: bishop x-ray-attacking the
square in front of enemy backward pawn,
part of the king shelter, on its 2nd rank, Scaling down of different positions and
with the own backwardmaker on the ray endings
between the bishop and the attacked
square
Scaling down of too closed positions
Value: bonus, 12cps, just for the mg
In case all 8 files are closed with pairs of
Additional information: the bonus is very blocked pawns or pairs of symmetrical
well due, as this not only highlights the twice backward pawns, the positional
weakness of the backward pawn, but, as score(the estimate of all positional
the pawn will constitute part of the enemy advantages) should be adjusted to
shelter, this has immediate consequences 0.0/draw, provided that the stronger side
upon the king safety, rendering the shelter leads by less than 200cps(so, if your top
as a whole more inflexible. engine shows +200cps advantage for one
side or lower in such a position, the actual
score is of course 0.0/complete draw).
The reason for the 200cps particular value
is the fact that, in order for the stronger
side attempting to break through, it needs
to sacrifice at least a piece for a single
enemy pawn.

the bishop on b2, x-ray-controlling the f6

square in front of the black f7 shelter
pawn, that is backward on its 2nd rank,
with the own e5 backwardmaker on the ray
between the bishop and the attacked
square, makes the black shelter even more
inflexible.
In order to defend, black will have well, one might be inclined to think black
sometimes to push f7-f6/f7-f5, and, after has substantial/winning advantage,
the capture of the backward pawn, this will because of its 6 advanced pawns into the
lead to the breakdown of the shelter. enemy half of the board, but no, this is a

267
simple draw(which top engines would still
fail to recognise)

still very difficult to break through

sometimes, even a piece more would not Horizontal pawn symmetry

be sufficient to win the game
In case all own pawns are opposed by an
enemy pawn, and positional score is lower
than 50cps, it should be adjusted by
halving it.
Horizontal symmetry of all available own
and enemy pawns is simply more drawish
than otherwise, as in such a case there are
no passers that could promote, no potential
passers to create danger, while efficient
breaks are made more difficult by the fact
that the position as a whole is easier to
close.
Reason for the particular 50cps score is an
objective estimate of drawing chances.

and one variation with a series of twice

backward pawns(still a draw)

In case not all 8, but only 7 files on the

board are closed by pairs of blocked pawns
or pairs of symmetrical twice backward
pawns, the positional score should be
adjusted to 0.0/draw, provided that its
value is less than 100cps.

268
horizontal pawn symmetry is much more well, this is an easy draw, even though
drawish than otherwise, of course; in case white is a pawn up
c5-c4 is played, white might avoid the
break by pushing b3-b4, while after f3-f4
break attempt, black could support the e5
pawn with f7-f6, still holding onto the
horizontal symmetry

Opposite colour bishops

In case one side has only one bishop, and

the other side also has a single bishop,
with both bishops placed on squares of
different colour, the positional score
should be adjusted, to one third of its value
in the mg, and one half of its value in the
eg, provided that the score is lower than
100cps.
The reason is obvious, and frequently more pieces in the eg basically change
easily recognisable by stronger humans, nothing: white does not have an easy time
while even top engines sometimes have to convert at all
significant difficulties to understand why
similar positions are much more drawish.
With values higher than 100cps advantage,
it is difficult to hold such positions in the
general case, though there are exceptions,
of course.

269
no matter one side might have a bit of an it is difficult to imagine one side could
advantage, it is pretty much nullified also win, so drawish are such endgames in a
in the mg with the presence of lots of pure setting
pieces

Pairs of bishops endgame

Definition: both sides having one pair of

bishops each in the endgame

Value: score could be scaled down by

some 20% or so, if lower than 100cps, as
such endgames are very drawish

Additional information: the scaling-

down of the endgame is necessary, as
similar endgames will frequently lead to
draws, unless one side has a substantial
advantage.
The reason is simple, although not many with more pieces added, such endgames
authors have noted it: in the 2 pairs of are still very equal
bishops you have in a way 2 separate pairs
of opposite colour bishops, and, as we all Frequency: infrequent
know very well, opposite colour bishops
tend to be very drawish in general.
Of course, above condition is not felt very General endgame scaling
strongly, as the pairs play in tandem, but
still, it is quite real. If total non-pawn material(the cumulative
value of all own plus all enemy non-pawn
pieces) on the board is less than 1/4 of the
initial non-pawn material(the material at
the start of the game), the positional score

270
should be halved, provided that it is lower Scaling with reduced number of pawns
than 80cps. in the eg
Well, that should see drawish positions
with very few pieces, and also some If one side has a single pawn, and the other
fortresses. The particular 80cps value is side has no pawns at all, the positional
due to the fact that 80cps is more or less score should be adjusted to 7/10 of its
the drawing margin in the eg. value, provided that it is lower than
150cps.
Obviously, such endings are very drawish
in view of the almost complete lack of
resources(with a single pawn, non-pawn
pieces will be few too), so one might scale
them down boldly.

well, it is difficult for black to win

that(engines would still show significant
black advantage)

well, this is an eye-scratching draw

pawns on both wings change nothing; still

pretty much a draw

and also this one, in spite of the bigger

number of non-pawn pieces

271
If one side has 2 pawns, and the other side straightforward draw too, though some top
one pawn, and there are no passers, or, if engines might still think black is winning
one side has 3 pawns, and the other side in terms of positional score
has 2 pawns, and there are no passers, the
positional score should be adjusted to half
of its value, provided that it is lower than Scaling of rook endgames
100cps.
Reason is obvious: too few material and Definition: single rook endgame, each
very difficult or impossible to create side having only one rook, if there are no
passers. Quite probably, the ratio of 3 to 2 passers, and the positional score is less
pawns will later get to a 2:1 ratio, and then than 80cps
to a single pawn vs no pawns ratio, so
drawing chances will always be big. Value: the assessment of the position, the
positional score, should be scaled down by
half

Additional information: single rook

endgames, with no passed pawns, and
relatively small score, tend to generally be
very drawish.
So, it would be nice to actually consider
them as such, instead of preferring them in
the place of other, objectively much better
lines.

very easy draw; sometimes, engines, even

top ones, would still think the stronger side
has good winning chances

black does not have a way of winning this,

in spite of its small positional advantage

272
 king of the queen side is not past its 5th
rank

nor white this one

the diagram reflects the required

conditions. There are no passers for the
queen side, the queen side pawn is an h
one, the rook is defended by a pawn on the
g file on its 2nd rank, adjacent to the king,
and the black king has not crossed the 5th
rank.

Value: under such circumstances, the

score is automatically adjusted to 0cps
advantage, draw by fortress

Additional information: well, those are

simply theoretically drawn endings.

this one is unwinnable by the stronger As easily seen on the diagrammed

side, too position, the stronger side can not win, as
nothing could be done to break the white
Frequency: very frequent positional fortress. The black pawn can not
pass beyond its 5th rank, as on h3 it will be
captured by the rook, with the support of
Rook vs queen fortress in the endgame the g2 pawn, the black king can not
penetrate beyond its 5th rank, for the very
Definition: one side having just one same reason, the white rook is controlling
queen, and at most a single pawn, with the the entire third row, and it is supported, the
other having just one rook, and at least one white king is in a corner, sheltered by the
pawn, if the queen side has no passers, the pawn and rook, while the black queen can
rook is protected by a pawn on the g or b not mate the king alone without the help of
files on its 2nd rank, the king of the rook the friendly king.
side is adjacent to that pawn, the pawn of So, white just shuffles around with the
the queen side is on files h,f,a or c, and the rook and king, until draw is achieved.

273
sometimes, more pawns for the stronger
side will also lead to draw, but the
conditions are too plentiful to enumerate
them all. Fortress recognition is a difficult
thing, on which thousands pages could be
written, so here we will just limit ourselves
to this one.

Frequency: infrequent

274
 Alphabetical index of terms

absolute pin(see king pin)

advanced lever

advanced pawn

aligned pawn

apex pawn(see twice defended pawn)

backward-fated pawn(see twice backward pawn)

backwardmaker

backward long chain pawn

backwardness

backward opposed pawn

backward pawn

backward shelter pawn

backward unopposed pawn

battery

bind

bishop mobility

bishop outpost

bishop pair

bishop psqt

blockade

blockader

blocked center

275
blocked chain

blocked doubled pawn

blocked file

blocked pawn

blocked pawn structure

blocked position

blocked storming pawn

blocker

blocking outpost

blocking pawn

break

caged piece

caging

candidate passer

castling

castling rights

center control

centipawn

central attack

central backwardmaker

central bind

central chain

central chain blockade

centralisation

276
central isolated pawns

central wedge

chain

chain backward pawn

chain pawn see defended pawn

check

clamp

closed center

closed file

closedness

closed position

closed side

closed structure

closure

colour deficiency

compact pawn structure

complementarity

connected passed pawn

connected passer

connected pawn

connecting pawn

continuous control

counter-break

counterplay

cramped position

277
cramping

defended aligned pawn

defended outer central lever

defended pawn

defending aligned pawn

direct attack

distant backward pawn

distant neighbour

double attack

double base pawn see double root pawn

double check

doubled isolated pawn

doubled pawn

doubled rooks

doubled shelter pawn

double pawn push

double root pawn

drawing margin

duo pawn see aligned pawn

durability

edge file

edge line

edge storming pawn

278
empty square

endgame scaling

enemy camp

en passant

evaluation factor

evaluation framework

exposed king

extended center

fianchettoed bishop

fixed isolated pawn

flexible pawn structure

focal center

fork

fortress

free pawn

free square

fully closed side

gambit

hanging pawn

hanging piece

heavy piece

hole see weak spot

279
horizontal symmetry

imbalance

immobile pawn

immobile piece

immobile shelter pawn

immobilisation

immobility

inchoative pointed chain

inflexibility

inflexible pawn

inflexible shelter

intermediary object

interposition

isolated opposed pawn

isolated pawn

isolated shelter pawn

isolated unopposed pawn

king attack

king cover

king mobility

king pin

king position

280
king psqt

king safety

king shelter

king side

kingside attack

kingside castling

kingside fianchetto

kingside presence of pieces

king walk

king wing

knight attack threat

knight mobility

knight outpost

knight psqt

kicking

lever

levering

lever pawn

lever push

lone queen

long chain

long chain pawn

long diagonal

low mobility

281
M

mainstay

manoeuvering

mate

material

material imbalance

medium pawn(see long chain pawn)

minor

minor outpost

minor piece

minor piece shelter

minor piece shelter defence

mobile square

mobility

non-pawn material

no-pawn-defended bishop outpost

no-pawn-defended knight outpost

no-pawn-defended outpost

no pawn shelter

opener

open file

open position

opposed pawn

282
opposing pawn

opposite castling

opposite colour bishops

outer central lever

outpost

outposted minor

outposted rook

outpost square

overextended pawn(see vertically isolated pawn)

own camp

pair of bishops

pair of blocked pawns

pair of knights

pair of rooks

pairs of bishops

passed pawn

passer

passer-maker

pawn advance

pawn break

pawn chain

pawn cover

pawn defence

pawn mobility

283
pawn psqt

pawn push

pawn shelter

pawn span

pawn storm

pawns on both wings

pawn tension

pawn thrust

penetration

penetration point

permanently backward pawn

permanently trapped piece

permanent outpost

piece activity

piece attack

piece coordination

piece defence

piece value

pin

pinned piece

pinner

pointed chain

positional scaling-down

potential check

potential discovered check

284
potential passer

prevention of castling

promotion

protected passed pawn

protected passer

psqt

psqtise

push

queen mobility

queen pair

queen pin

queen psqt

queen side

queenside castling

queenside fianchetto

queen wing

raking bishop

redundancy

relative pin(see queen pin)

restricted mobility

restricting activity

restricting passer

retreat

285
rollercoaster

rook mobility

rook outpost

rook psqt

root pawn

royal battery

sac

sacrifice

safe check

safe pawn push threat

same colour pawns

self-trapped bishop

semibackward pawn

semi-backward shelter pawn

semi-central file

semi-central pawn

semi-closed file

semi-open file

semi-outpost

sentinel pawn

shelter attack

shelter pawn

shelter weak spot

side to move

286
simultaneous attack

single-pawn-defended bishop outpost

single-pawn-defended knight outpost

single-pawn-defended outpost

skewer

slider

sliding piece

space advantage

spearhead

spearhead connected passer

square control

squeeze

squeezed pawn

standard backward pawn

stormer

storming pawn

strong pawn

symmetrical aligned pawn

symmetrical doubled pawn

symmetrical twice backward pawn

tactical lever

tactical lever threat

tactical pawn threat

tempo

287
threat

trappable piece

trapped minor

trapped piece

trapped rook

tripled pawn

triplet

turn

twice aligned pawn

twice backward feature

twice backward opposed pawn

twice backward pawn

twice backward unopposed pawn

twice backward shelter pawn

twice-defended bishop outpost

twice defended knight

twice-defended knight outpost

twice-defended outpost

twice defended pawn

twice defended rook

twice defended storming pawn

unadvanced pawn

unattackable object

unbackwarded pawn

288
unblocked storming pawn

undefended minor piece

undefended pawn

undefended piece

undefended rook

undoubling

unlocking

unopposed backward-maker

unopposed lever

unopposed pawn

unretreatable outpost

unsafe check

unsafe pawn push threat

unstoppable passed pawn

untripling

useless outpost

vertically isolated pawn

very distant neighbour

very long chain pawn

weak pawn

weak spot

weak spot defence

289
X

x-ray attack

x-ray control

x-ray shelter attack

zero mobility

zugzwang

290