This webpage documents a minimal weak solution to Connect 4. The graph shown is an entire weak solution, which can be memorized in order to guarantee perfect play as player 1.
See the graph here, and some explanation here.
Steady-state diagrams that shrink the graph are welcome; see CONTRIBUTING.md. New diagrams are exhaustively verified automatically, and the representations are rendered from solution/steady_states.json and solution/branches.json after merge.