A typical Staunton-design set and clock ()

When the chess game is over, the pawn and the king go back to the same box
- Irish saying

Chess (the "Game of Kings") is a board game for two players, which requires 32 chesspieces (or chessmen) and a board demarcated by 64 squares. Gameplay does not involve random luck; it is based on tactics and strategy. Nevertheless, chess is so complex that even the best players can't consider all contingencies. The number of legal positions in chess is estimated to be between 1043 and 1050, and the game-tree complexity approximately 10123. Typically a position has thirty to forty possible moves, but there may be as few as zero (in the case of checkmate or stalemate) or as many as 218.

Chess is one of humanity's more popular games; it is has been described not only as a game, but also as both art and science. Chess is sometimes seen as an abstract wargame; as a "mental martial art". Chess is played both recreationally and competitively in clubs, tournaments, on-line, and by mail (correspondence chess). Many variants and relatives of chess are played throughout the world; amongst them, the most popular are Xiangqi (in China), Shogi (in Japan), and Buddhi Chal (in Nepal), all of which come from the same historical stem as chess.


Although many countries make claims to have invented it, the preponderance of evidence is that chess originated from the Indian game Chaturanga, about 1400 years ago. It reached Russia via Mongolia, where it was played at the beginning of the 7th century. From India it migrated to Persia, and spread throughout the Islamic world after the Muslim conquest of Persia. It was introduced into Spain by the Moors in the 10th century, where a famous games manuscript covering chess, backgammon, and dice named the Libro de los juegos, was written under the sponsorship of Alfonso X of Castile during the 13th century. Chess reached England in the 11th century, and evolved through various versions such as Courier.

By the end of the 15th century, the modern rules for the basic moves had been adopted from Italy: pawns gained the option of moving two squares on their first move and the en passant capture therewith; bishops could move arbitrarily far along an open diagonal (previously being limited to a move of exactly two squares diagonally) while losing the ability to jump over the intervening square, and the queen was allowed to move arbitrarily far in any direction, making it the most powerful piece. (Before, she could only move one square diagonally.) There were still variations in rules for castling and the outcome in the case of stalemate.

These changes collectively helped make chess more open to analysis and thereby develop a more devoted following. The game in Europe since that time has been almost the same as is played today. The current rules were finalized in the early 19th century, except for the exact conditions for a draw.

The most popular piece design, the "Staunton" set, was created by Nathaniel Cook in 1849, endorsed by a leading player of the time Howard Staunton, and officially adopted by FIDE in 1924.

Staunton styled himself the first World Champion of Chess in the 1850s; however he lost a short match to Adolf Anderssen and avoided playing Paul Morphy. The first player to stake a widely recognized claim to being World Champion was Wilhelm Steinitz in 1866, as Steinitz willingly played (and won) matches against all of his rivals.

The title "Grandmaster" was created by Russian Tsar Nicholas II who first awarded it in 1914 to five players after a tournament he had funded in Saint Petersburg.

The World Chess Federation (FIDE) was founded in 1924. When the reigning World Champion Alexandre Alekhine died in 1946, FIDE took over the function of organizing World Championship matches. Before that time, sitting champions had been somewhat capricious in determining against whom and on what terms they would accept a challenge match. FIDE also assumed the role of awarding the titles Grandmaster and International Master, as well as eventually assigning numerical ratings to players.

In 1993, in the middle of a cycle of matches to determine the World Champion, Garry Kasparov and Nigel Short broke with FIDE to organize their own match for the title. They complained of corruption and a lack of professionalism within FIDE, and formed a competing Professional Chess Association. Since then there have been two simultaneous World Champions and World Championships: one extending the Steinitzian lineage in which the current champion plays a challenger in match format (a series of many games); the other following FIDE's new format of a tennis-style elimination--or "Knockout"--tournament with dozens of players competing.

Once considered only a curiosity, computer chess programs have risen in ability to the point where they can seriously challenge human grandmasters.

Kasparov, then ranked number one in the world, played a six-game match against IBM's chess computer Deep Blue in 1996. Deep Blue shocked the world by winning the first game in Deep Blue - Kasparov, 1996, Game 1, but Kasparov convincingly won the match by winning 3 games and drawing 2. The six-game rematch in 1997 was won by the machine which was subsequently retired by IBM. In October, 2002, Vladimir Kramnik drew in an eight-game match with the computer program Deep Fritz. In 2003, Garry Kasparov drew both a six-game match with the computer program Deep Junior in February, and a four-game match against X3D Fritz in November.

In May 2002, several leaders in the chess world met in Prague and signed a unity agreement which intended to ensure the crowning of an undisputed world champion before the end of 2003, and restore the traditional cycle of qualifying matches by 2005. The semifinalists for the 2003 championship were to be Ruslan Ponomariov vs. Gary Kasparov, and Vladimir Kramnik vs. Peter Leko. The former match, organised by FIDE, had been scheduled to take place in Yalta beginning on September 18, 2003, but was called off on August 29 after Ponomariov refused to sign his contract for it. There is a proposal that Kasparov will instead play a match in 2004 against the winner of the next FIDE knock-out world championship. The Kramnik-Leko match was originally to be held in Budapest, but funding collapsed and it was called off. Therefore there is unlikely to be an undisputed World Champion any time soon.

At one time, chess games were recorded using Descriptive chess notation, a somewhat clumsy notation that takes more space, more time to say, and more time to explain than its replacement, algebraic chess notation. Portable Game Notation (PGN) is the most common standard computer-processable format for recording chess games, and is based on algebraic chess notation.

Subject overview

See also: Chess problems, ELO rating system

For secondary uses of the word "chess" see