Cylinder chess

Cylinder chess is a chess variant played on a board whose left and right edges are treated as joined together, so that a piece moving off one side of the board reappears on the opposite side as though the board were wrapped into a cylinder. All standard chess pieces and the ordinary rules of check, checkmate, and stalemate carry over unchanged from orthodox chess; only the geometry of the board itself is altered. The variant is closely associated with the tradition of fairy chess problems, in which composers devise unconventional boards and rule changes to produce puzzles impossible on a standard flat board, and the cylindrical board remains a recognized device within that problem-composing tradition. The wraparound geometry has a substantial effect on piece strength, most notably making bishops considerably more powerful than in orthodox chess, since a bishop's diagonal can continue around the cylinder and reach squares that would be completely unreachable on a flat board, creating tactical possibilities that do not exist in the standard game.