The board game in which players castle to protect their king and/or develop a rook is called Chess. To castle, the king and rook being castled can not have moved, the king may not be in check, there may not be a piece between the castling king and rook, and an opponent's piece may not be attacking the squares in which the king moves. To castle, the king moves two squares either towards the kingside rook or the queenside rook, and the rook is placed on the square the king passed through.
Castling takes one chess turn.
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