Rook (chess)


The rook is a piece in the game of chess resembling a castle. Formerly the piece was called the tower, marquess, rector, and comes. The term castle is considered to be informal, incorrect, or old-fashioned.
Each player starts the game with two rooks, one on each of the corner squares on their own side of the board.

Placement and movement

The white rooks start on squares a1 and h1, while the black rooks start on a8 and h8. The rook moves horizontally or vertically, through any number of unoccupied squares. As with captures by other pieces, the rook captures by occupying the square on which the enemy piece sits. The rook also participates, with the king, in a special move called castling.

Strategy

Relative value

In general, rooks are stronger than bishops or knights and are considered greater in value than either of those pieces by nearly two pawns but less valuable than two minor pieces by approximately a pawn. Two rooks are generally considered to be worth slightly more than a queen. Winning a rook for a bishop or knight is referred to as winning the exchange. Rooks and queens are called heavy pieces or , as opposed to bishops and knights, the minor pieces.

Development

In the opening, the rooks are blocked in by other pieces and cannot immediately participate in the game, so it is usually desirable to connect one's rooks on the first by castling and then clearing all pieces except the king and rooks from the first rank. In that position, the rooks support each other and can more easily move to occupy and control the most favorable.
A common strategic goal is to a rook on the first rank of an open file or a half-open file. From this position, the rook is relatively unexposed to risk but can exert control on every square on the file. If one file is particularly important, a player might advance one rook on it, then position the other rook behind—doubling the rooks.
A rook on the seventh rank is typically very powerful, as it threatens the opponent's unadvanced pawns and hems in the enemy king. A rook on the seventh rank is often considered sufficient compensation for a pawn. In the diagrammed position from a game between Lev Polugaevsky and Larry Evans, the rook on the seventh rank enables White to draw, despite being a pawn down.
Two rooks on the seventh rank are often enough to force victory, or at least a draw by perpetual check.

Endgame

Rooks are most powerful towards the end of a game, when they can move unobstructed by pawns and control large numbers of squares. They are somewhat clumsy at restraining enemy pawns from advancing towards promotion, unless they can occupy the file behind the advancing pawn. As well, a rook best supports a friendly pawn towards promotion from behind it on the same file.
In a position with a rook and one or two minor pieces versus two rooks, generally in addition to pawns, and possibly other pieces – Lev Alburt advises that the player with the single rook should avoid exchanging the rook for one of his opponent's rooks.
The rook is a very powerful piece to deliver checkmate. Below are a few examples of rook checkmates that are easy to force.

History

In the medieval shatranj, the rook symbolized a chariot. The Persian word rukh means chariot, and the corresponding piece in the original Indian version chaturanga has the name ratha. In modern times it is mostly known as हाथी to Hindi-speaking players, while east Asian chess games such as xiangqi and shogi have names also meaning chariot for the same piece.
Persian war chariots were heavily armored, carrying a driver and at least one ranged-weapon bearer, such as an archer. The sides of the chariot were built to resemble fortified stone work, giving the impression of small, mobile buildings, causing terror on the battlefield.
In Europe the castle or tower appears for the first time in the 16th century in Vida’s Ludus Scacchia, and then as a tower on the back of an elephant. In time, the elephant disappeared and only the tower was used as a rook.
In the West, the rook is almost universally represented as a crenellated turret. The piece is called torre in Italian, Portuguese, and Spanish; tour in French; toren in Dutch; Turm in German; torn in Swedish; and torni in Finnish. In Hungarian it is bástya and in Hebrew language it is called צריח. In the British Museum's collection of the medieval Lewis chess pieces the rooks appear as stern warders, or wild-eyed Berserker warriors.
Rooks usually are similar in appearance to small castles, and as a result a rook is sometimes called a "castle".
In modern chess literature this term is rarely, if ever, used.
In some languages the rook is called a ship: Thai เรือ, Armenian Նավակ, Russian ладья, Javanese ꦥꦫꦄꦲꦸ. This may be because of the use of an Arabic style V-shaped rook piece, which some may have mistaken for a ship. It is possible that the rendition comes from Sanskrit roka, but this was challenged by the fact that no chaturanga pieces ever called a roka. Murray argued that the Javanese could not visualize a chariot moving through the jungles in sweeping fashion as the rook. The only vehicle that moved in straight fashion was ship, thus they replaced it with prahu. Murray, however, did not give explanation about why the Russians called it a ship.
In Bulgarian, it is called the cannon.
In Kannada, it is known as ಆನೆ, meaning "elephant". This is unusual, as the term "elephant" is in many other languages applied to the bishop.

Heraldry

Chess rooks frequently occur as heraldic charges. Heraldic rooks are usually shown as they looked in medieval chess-sets, with the usual battlements replaced by two outward-curving horns. They occur in arms from around the 13th century onwards.
In Canadian heraldry, the chess rook is the cadency mark of a fifth daughter.

Unicode

defines two codepoints for rook:
♖ U+2656 White Chess Rook
♜ U+265C Black Chess Rook