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
Fork (chess) Fork (chess) In chess, a fork is a tactic whereby a single piece makes two or more direct attacks simultaneously. Most commonly two pieces are threatened, which is also sometimes called a "". The attacker usually aims to gain by one of the opponent's pieces. The defender often finds it difficult to counter two or more threats in a single move. The attacking piece is called the "forking" piece; the pieces attacked are said to be "forked". A piece that is defended can still be said to be forked if the forking piece has a lower value. Besides attacking pieces,