When a player moves a piece to a position where it directly threatens the opponent's king, that king is said to be in check. The player putting the opponent's king in check must announce, "Check." The player with a king in check must respond by escaping. There are three ways to escape:
• capture the checking piece
• block the checking piece
• move the king out of check
In this example, a rook moves from a3 to c1, putting the white king in check. The black rook is too close to the white king to be blocked. White can escape check by capturing the checking rook with the white rook, or White can move the king out of check to d2.