| a | b | c | |||
| 3 |  |  | | 3 | |
| 2 |  |  | | 2 | |
| 1 |  |  | | 1 | |
| a | b | c |
Hexapawn is a deterministic two-player game invented by Martin Gardner. It is played on a rectangular board of variable size, for example on a 3×3 board or on a regular chessboard. On a board of size n×m, each player begins with m pawns, one for each square in the row closest to them. The goal of each player is to either advance a pawn to the opposite end of the board or leave the other player with no legal moves, either by stalemate or by having all of their pieces captured.
Hexapawn on the 3×3 board is a solved game; with perfect play, White will always lose in 3 moves (1.b2 axb2 2.cxb2 c2 3.a2 c1#). Indeed, Gardner specifically constructed it as a game with a small game tree in order to demonstrate how it could be played by a heuristic AI implemented by a mechanical computer based on Donald Michie's Matchbox Educable Noughts and Crosses Engine (MENACE).
A variant of this game is octopawn, which is played on a 4×4 board with 4 pawns on each side. It is a forced win for White.
Only 24 matchboxes are required for a hexapawn version of Matchbox Educable Noughts and Crosses Engine.