Chess king

The king (♔, ♚) is the most important piece in chess. He can move to any adjacent square; he can also perform a move known as castling. If a player's king is threatened with capture, it is said to be in check and the player must remove the threat of capture on the next move. If this cannot be done, the king is said to be in checkmate, resulting in a loss for that player. A player cannot make any move that puts his own king in check. Despite this, the king can become a strong offensive piece in the late game or, rarely, in the mid game.