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 David Parlett used a notation to describe fairy piece movements. The move is specified in the form m={"expression"}, where "m" stands for "move", and the "expression" is composed from the following elements: The following can be added to Parlett's to make it more complete: The format (not including grouping) is: <conditions> <move type> <distance> <direction> <other> On this basis, the traditional chess moves (excluding castling and "en passant" capture) are: Ralph Betza created a classification scheme for fairy chess pieces (including standard chess pieces) in terms of the moves of basic pieces with modifiers. Capital letters stand for basic leap