Rook

The rook moves in a straight line along a horizontal row, called a rank, or a vertical column, called a file. It may travel any number of squares, but it cannot jump over another piece. A friendly piece stops it before that square; an enemy piece may be captured on that square, but the rook cannot continue beyond it.

Each player begins with two rooks in the four corners of the board. A rook is a major piece, the category containing rooks and queens, and is commonly valued at about five pawns. Its reach grows when rows or columns are clear, so a rook trapped behind its own pawns may have few useful moves even though its conventional value has not changed.

The rook also participates in castling, a special move involving a king and a rook that have not moved, provided the other legal conditions are satisfied. Outside castling, the rook keeps its ordinary movement and never jumps.