Pin (chess) Pin (chess) In chess, a pin is a situation brought on by an attacking piece in which a defending piece cannot move without exposing a more valuable defending piece on its other side to capture by the attacking piece. Moving the attacking piece to bring on the pin is called pinning; the defending piece so restricted is described as pinned. Only pieces that can move an indefinite number of squares in a horizontal, vertical, or diagonal line (i.e. bishops, rooks, and queens) can pin. Kings, knights, and pawns cannot pin. Any piece can be pinned except the king, since the
Pocket Mutation Chess Pocket Mutation Chess Pocket Mutation Chess is a chess variant invented by Mike Nelson in 2003. In this game a player can take a piece from the board and put it into a "pocket". The piece in the pocket can be put back on the board later. When placing the piece into the pocket the player can "mutate" the piece, i.e. change it to a different piece. The game is one of the "Recognized Chess Variants" at "The Chess Variant Pages". The starting position in this game is the same as in standard chess. Players make moves as in standard