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
Fairy chess piece Pieces invented for use in chess variants rather than problems sometimes instead have special icons designed for them, but with some exceptions (the princess, empress, and occasionally amazon), many of these are not used beyond the individual games they were invented for. Today's chess exists because of variations someone made to the rules of an earlier version of the game. For example, the queen we use today was once able to move only a single square in a diagonal direction, a "ferz". Today, this piece still starts next to the king, but has gained new movement and became today's queen.