Monochromatic chess d2 and f2, the white king can move from e1 only with castling and then g1–h2–g3–... so the pawn on g3 cannot be white. In Bichromatic chess, the opposite restrictions apply. A piece on a white square must move to a black square and vice versa. Hence pawns cannot capture (or advance two squares) and bishops cannot move. Also, castling and "en passant" are impossible, and queens behave like rooks. Monochromatic chess Monochromatic chess is a chess variant with unknown origin. The initial board position and all rules are the same as in regular chess, except that pieces that begin
Touch-move rule Touch-move rule The touch-move rule in chess specifies that, if a player deliberately touches a piece on the board when it is his turn to move, then he must move or capture that piece if it is legal to do so. If it is the player's piece that was touched, it must be moved if he has a legal move. If the opponent's piece was touched, it must be captured if it can be captured with a legal move. This is a rule of chess that is enforced in all games played in formal competitions. The player claiming a touch-move