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
Sacrifice (chess) Sacrifice (chess) In chess, a sacrifice is a move giving up a piece with the objective of gaining tactical or positional compensation in other forms. A sacrifice could also be a deliberate exchange of a chess piece of higher value for an opponent's piece of lower value. Any chess piece except the king may be sacrificed. Because players usually try to hold on to their own pieces, offering a sacrifice can come as an unpleasant surprise to one's opponent, putting him off balance and causing much precious time to be wasted trying to calculate whether the sacrifice is sound or