Rook (Chess)

The rook (also called a castle) is one of the pieces in chess. Each player begins with two rooks, placed on the two corners of the back rank. The rook is a powerful piece that moves along straight lines, and is considered high in value when compared to the knight and bishop.

The conventional depiction of a rook is a tower or battlement. The Somali name daar derives from the appearance of a building, while other languages use terms such as 'tour' (French) or 'kale' (Turkish, meaning castle).

Movement

A rook can move any number of squares along a rank (horizontal line) or file (vertical line). It cannot move past another piece; if a piece belonging to the same side stands in its path, the rook must stop before it, or if it is an opposing piece, the rook may capture it. Capture occurs on the square where the opponent's piece stands.

Castling

The rook participates in a special move called castling, the only move in which two pieces move simultaneously. The king moves two squares toward the rook, and the rook moves to the square the king has crossed. Castling requires that both the king and rook have not yet moved, that the squares between them are empty, and that the king is not in check, is not moving through check, or moving into check.

Value and use

In the standard point system used in chess, a rook is valued at five points (pawns), whereas the knight and bishop are valued at approximately three. Therefore, trading a rook for a knight or bishop is called winning the exchange. The rook's power increases when the board is open, especially with clear files, and when two rooks are connected or placed on the seventh rank of the opponent's side.

Endgames

A king and rook alone can checkmate a lone king by driving it to the edge or back rank. Rook and pawn endgames are the most common type arising from tournament games, and there are established principles such as the Philidor defense and the Lucena technique.