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
Empress (chess) attacking archbishop two squares diagonally away), while the rook+knight compound cannot. Worse, the word empress suggests a piece stronger than the queen, while this piece is at best equal to and perhaps weaker than the queen, especially in the endgame. The empress was first used in Turkish Great Chess, a large medieval variant of chess, where it was called the "war machine" (dabbabah; not to be confused with the piece more commonly referred to as the dabbaba today, which is the (2,0) leaper). It was introduced in the West with Carrera's chess from 1617, where it was called a "champion",