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
Madrasi chess on g2). In addition to Madrasi RI, another variant is Isardam ("Madrasi" spelled backwards), in which only moves that do not lead to a Madrasi paralysis are legal. Madrasi chess Madrasi chess is a chess variant invented in 1979 by Abdul Jabbar Karwatkar. The game uses the conventional rules of chess with the addition that when a piece is attacked by a piece of the same type but opposite colour (for example, a black queen attacking a white queen) it is paralysed and becomes unable to move, capture or give check. Most of the time, two like pieces attack each