Exchange (chess) to as a "recapture". Commonly, the word "exchange" is used when the pieces exchanged are of the same type or of about equal value, which is an "even exchange". According to chess tactics, a bishop and a knight are usually of about equal value. If the values of the pieces exchanged are not equal, then the player who captures the higher value of piece(s) can be said to be "up the exchange" or "wins the exchange", while the opponent who captures the lower value of piece(s) is "down the exchange" or "loses the exchange". Exchanges occur very frequently in chess,
Chess is under attack, or a stalemate (a draw) if the king is not. Each chess piece has its own way of moving. In the diagrams, the dots mark the squares where the piece can move if there are no intervening piece(s) of either color. Once in every game, each king is allowed to make a special move, known as "castling". Castling consists of moving the king two squares along the first rank toward a rook (which is on the player's first rank) and then placing the rook on the last square that the king has just crossed. Castling is permissible