rooks

Rooks are a chess piece used by both players. Each side begins with two rooks on the a1 and h1 squares for White and a8 and h8 for Black. A rook moves any number of unoccupied squares along a rank or file and cannot jump over other pieces. It is valued at five points and is especially powerful in open files and endgames, where it coordinates with the king to control lines. Castling is a special move that develops a rook while safeguarding the king: the king moves two squares toward a rook, and the rook lands on the square the king passed over. Castling is allowed only if neither piece has moved, the squares between are unoccupied, the king is not in check, and the king does not pass through a square attacked by an opponent. Rooks are particularly strong when paired on a file, forming a rook battery. In many sets the rook is depicted as a castle turret; the name derives from early chess roots in India and Persia.

The rook, Corvus frugilegus, is a crow found across Europe. Adults are largely black with a pale bare face at the base of the bill and a bluish gloss on the wings. They are highly social and form large communal roosts. Diet is omnivorous, including invertebrates, seeds, grain, and scraps. Nests are built high in trees, and clutches typically contain three to five eggs. Foraging occurs in fields and pastures near farmland; rooks can be crop pests but also contribute to pest control and seed dispersal. Rooks are widespread and not currently threatened.