What is King?

The King is one of the most crucial pieces on the game board. It can move in any direction but only one square at a time. The objective of the game is to checkmate the opponent's King, which means the King is in position to be captured (in check) and there is no way to remove the threat of capture on the next move. If a player's King is threatened with capture, they must remove that threat immediately on their turn. The game is lost if it is not possible to remove the threat of capture to the King.

See Moving the king.