Ploy is an abstract strategy board game for two or four players, played on a 9×9 board with a set of 15 pieces (2-handed) or 9 pieces (4-handed and partnership games) per player. Pieces have various horizontal, vertical or diagonal moves somewhat like chess pieces, except directions of movement are limited; pieces change directions of movement by “rotating”. Object of the game is to capture the opponent’s Commander (analogous to the king in chess), or all of his other pieces.
It was invented by Frank Thibault and commercially released by 3M Company in 1970, as part of the 3M bookshelf game series. The game is marketed as a “space-age strategy game”. It is also considered to be one of the “better” chess variations.