The rook is a major piece in chess that moves any number of squares in a straight line — horizontally or vertically — and cannot jump over other pieces.
Easily recognised by its castle-like silhouette, the rook is one of the most powerful pieces on the board. It is conventionally valued at 5 pawns, placing it above the minor pieces (bishops and knights, each worth roughly 3 pawns). On an empty board, a rook always controls exactly 14 squares from any square it occupies (7 along its rank and 7 along its file), making its range of influence enormous.
In practice, the rook tends to be underused in the opening because it requires open space to become active. It reaches its full potential on open files (files with no pawns blocking them), half-open files, and especially in the endgame, where it excels at supporting passed pawns or chasing down the opponent’s king. Two rooks working together on the same file or rank form a powerful battery capable of seizing entire lines or delivering checkmate. One of the most important principles for rook play is to place it on an open file as early as possible — an opportunity that naturally arises after castling.