This is a film about a ninja called Kamui who decides he doesn't want to be a ninja anymore, problem is, you're not allowed to leave. So death in all it's forms is going to come for Kamui throughout this film. This spawns the familiar trope of the hero who stays alive but gets everyone around him, including his loved ones, killed (like the hardboiled American cop who goes through a fistful of partners as if they were dimes for the telephone). Kamui reminds me of a deciduous tree, the trunk of which remains strong and constant, but whose leaves eventually wilt and abscice. The bounteous autumnal melange of colours preceding the winter barrenness.
It's chambara here all the way, and as it's very ambitious, it's often CGId - wire work can only take you so far in the arena of awesome stunts. The fighters here have really pretty much supernatural skills that make Crouching Tiger look positively undercooked. There's some fun stuff that Kamui fights with, including a knuckleduster with triangular ridges, that can be used for parrying sword blows (though you'd better be pretty accurate with those parries...)
As Kamui (Ken'ichi Matsuyama) is a really rather sullen character, who has appeal more as a heartthrob to potential androphile members of the audience, much of the ready humour in the film is delegated to supporting actors including Kaoru Kobayashi (as Hanbei the fisherman), and Hideaki Ito (as Lord Fudoh, the incredibly appealing and roguish pirate captain).
There's a side story in the movie about a gaily apparelled and brutally petulant daimyo lord. The stories do crossover, but I think the daimyo strand is more there for contrast, the kind of easy god-like existence of the highly undeserving daimyo, with the bleak struggle to survive of Kamui. After all the main threat for Kamui is the ninja fraternity, he's not even a speck on the daimyo's radar.
There's this thing in Japanese movies where they like to confront characters with a personal hell (one of the few Japanese words I regularly recognise in Japanese movies is jigoku - hell). There's a quite effective example of that in this movie.
All in all I would tend to say this movie overdoes the CGI, you can see stuff like waves that leave no filmy coating on surfaces after they recede, and you think hang on why are they using CGI for ... water. It is however highly enjoyable.
One last note is that someone behind the movie should learn a little bit more about shark behaviour maybe, the scenes with them in are funny, but they behave so stupidly and atypically here that it is a little bewildering, even within the encapsulated cinematic world of reduced realism.
