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Chess is a board game for two players, played on a square chessboard consisting of 64 squares arranged in an 8×8 grid. The players, referred to as "White" and "Black", each control sixteen Chess piece: one king, one queen, two rooks, two bishops, two knights, and eight pawns, with each piece type having a different pattern of movement. An enemy piece may be captured (removed from the board) by moving one's own piece onto the square it occupies. The object of the game is to "checkmate" (threaten with inescapable capture) the enemy king. There are also several ways a game can end in a draw.
The recorded history of chess dates back to the emergence of chaturanga in 7th-century India. Chaturanga is also thought to be an ancestor of Chess variant like , , and . After its introduction to Persia, it spread to the Arab world and then to Europe. The modern rules of chess emerged in Europe at the end of the 15th century, becoming standardized and gaining universal acceptance by the end of the 19th century. Today, chess is one of the world's most popular games, with millions of players worldwide.
Organized chess arose in the 19th century. International chess competitions today are governed by the International Chess Federation FIDE ( Fédération Internationale des Échecs). The first universally recognized World Chess Champion, Wilhelm Steinitz, claimed his title in 1886; Gukesh Dommaraju is the current World Champion, having won the title in 2024.
A large body of chess theory has developed since the game's inception. Aspects of art are found in chess composition, and chess has in turn influenced Western culture and the arts, and has relevance to other fields such as mathematics, computer science, and psychology. One of the goals of early computer scientists was to create a chess-playing machine. In 1997, Deep Blue became the first computer to win a match with a reigning World Champion when it defeated Garry Kasparov. The of today are significantly stronger than the best human players and have greatly influenced the development of chess theory. Chess, however, is solving chess.
The game is played on a square Chessboard of eight rows (called ) and eight columns (called ). Although it does not affect gameplay, by convention the 64 squares alternate in color and are referred to as and squares.
To start the game, White's pieces are placed on the first rank in the following order, from left to right: rook, knight, bishop, queen, king, bishop, knight, rook. Pawns are placed on each square of the second rank. Black's position mirrors White's, with equivalent pieces on every file. The board is oriented so that the right-hand corner nearest each player is a light square; as a result the white queen always starts on a light square, while the black queen starts on a dark square. This may be remembered by the phrases "white on the right" and "queen on her color".
In informal games, colors may be decided either by mutual agreement, or by lot. The rules of chess do not prescribe any particular method for deciding colors by lot, but a common traditional method is to conceal a white pawn in one hand and a black pawn in the other and have the opponent choose.
In competitions, the piece colors are normally allocated to players by the organizers, but occasionally are decided by lot, for example in the first round of a player vs. player match or a team vs team match. In this case, the organizers are free to use any method they wish to decide the colors, from a simple coin toss or card draw, to more creative methods. For example at the U.S. China Chess Summit, a friendly match between the two countries played in Seattle in 2001, the first round colors were decided by a game of Jenga, won by the Chinese.
The object of the game is to checkmate the opponent; this occurs when the opponent's king is in check, and there is no legal way to get it out of check. In casual games, it is common to announce "check" when putting the opponent's king in check, but this is not required by the rules of chess and is usually not done in tournaments.United States Chess Federation. (2026). 9780812935592, Random House Puzzles and Games. ISBN 9780812935592
Castling is possible only if the following conditions are met:
Castling is still permitted if the rook is under attack, or if the rook crosses an attacked square. It is also still permitted if the king had been in check earlier in the game, provided that the check was resolved without moving the king.
Time is controlled using a chess clock with two displays, one for each player's remaining time. Analog chess clocks have been largely replaced by digital clocks, which allow for time controls with increments.
There are some aspects unique to online chess. A premove allows a player to submit a move on the opponent's turn, which gets played automatically if possible using little to no time. Premoves, alongside the relative ease of digital inputs, make ultrabullet feasible online.
Time controls are also enforced in correspondence chess competitions. A typical time control is 50 days for every 10 moves. Time is usually allotted per move in online correspondence chess.
For example, Qg5 means "queen moves to g5". Pawns have no letter initials; e4 simply means "pawn moves to e4". When multiple moves could be rendered the same way, the file or rank from which the piece moved is added to resolve ambiguity (e.g. Ngf3 means "knight from the g-file moves to the square f3"; R1e2 means "rook on the first rank moves to e2"). If a move may be disambiguated by rank or file, it is done by file, and in the rare case that both are needed, squares are listed normally (e.g. Qh4xe1).
If the move is a capture, "x" is usually inserted before the destination square, thus Bxf3 means "bishop captures on f3". When a pawn makes a capture, the file from which the pawn departed is often listed even when no disambiguation is necessary; for example, exd5 ("pawn on the e-file captures on d5").
If a pawn moves to its last rank, achieving promotion, the piece chosen is indicated after the move (for example, e1=Q or e1Q). Castling is indicated by the special notations 0-0 for castling and 0-0-0 for castling. A move that places the opponent's king in check usually has the notation "+" suffixed. Checkmate can be indicated by suffixing "#". At the end of the game, "1–0" means White won, "0–1" means Black won, and "½–½" indicates a draw. Chess moves can be annotated with punctuation marks and other symbols. For example: "!" indicates a good move; "!!" an excellent move; "?" a mistake; "??" a blunder; "!?" an interesting move that may not be best; or "?!" a dubious move not easily refuted.
Moves are written as White/Black pairs, preceded by the move number and a period. Individual moves by White are also recorded this way, while moves by Black are written with an ellipsis after the move number. For example, one variation of a simple trap known as the Scholar's mate (see animated diagram) can be recorded:
The move 3...Nf6?? is recorded as a blunder, as it allows 4.Qxf7 checkmate.
Games or sequences may be recorded in Portable Game Notation (PGN), a text-based file format with support for annotative symbols, commentary, and background information, such as player names. It is based on short form English algebraic notation incorporating markup language. PGN transcripts, stored digitally as PGN (.pgn) files can be processed by most chess software and are easily readable by humans.
Variants of algebraic notation include long algebraic, in which both the departure and destination square are indicated; abbreviated algebraic, in which capture signs, check signs, and ranks of pawn captures may be omitted; and figurine algebraic notation, used in chess books and magazines, which uses graphic symbols instead of initials to indicate pieces for readability regardless of language.
Until about 1980, the majority of English language chess publications used descriptive notation, in which files are identified by the initial letter of the piece that occupies the first rank at the beginning of the game. In descriptive notation, the common opening move 1.e4 is rendered as "1.P-K4" ("pawn to king four"). Another system, ICCF numeric notation, is recognized by the International Correspondence Chess Federation.
In tournament games, players are normally required to keep a (written record of the game). This is a requirement in all FIDE-sanctioned games played at classical time controls. For this purpose, only algebraic notation is recognized by FIDE, though variants such as long algebraic are acceptable; game scores recorded in a different notation system may not be used as evidence in the event of a dispute.
| + Example of underlying pawn structure |
Chess strategy is concerned with the evaluation of chess positions and with setting up goals and long-term plans for future play. During the evaluation, players must take into account numerous factors such as the value of the pieces on the board, control of the center and centralization, the pawn structure, king safety, and the control of or groups of squares (for example, diagonals, open files, and dark or light squares).
The most basic step in evaluating a position is to count the total value of pieces of both sides. The point values used for this purpose are based on experience; usually, pawns are considered worth one point, knights and bishops about three points each, rooks about five points (the value difference between a rook and a bishop or knight being known as the exchange), and queens about nine points. The king is more valuable than all of the other pieces combined, since its checkmate loses the game, but is still capable as a fighting piece; in the endgame, the king is generally more powerful than a bishop or knight but less powerful than a rook. These basic values are then modified by other factors like position of the piece (e.g. advanced pawns are usually more valuable than those on their initial squares), coordination between pieces (e.g. a pair of bishops usually coordinate better than a bishop and a knight), or the type of position (e.g. knights are generally better in with many pawns while bishops are more powerful in ).
Another important factor in the evaluation of chess positions is pawn structure (sometimes known as the pawn skeleton): the configuration of pawns on the chessboard. Since pawns are the least mobile of the pieces, pawn structure is relatively static and largely determines the strategic nature of the position. Weaknesses in pawn structure include Isolated pawn, Doubled pawns, or and ; once created, they are often permanent. Care must therefore be taken to avoid these weaknesses unless they are compensated by another valuable asset (for example, by the possibility of developing an attack).
Theoreticians describe many elementary tactical methods and typical maneuvers, for example: pins, forks, skewers, batteries, discovered attacks (especially discovered checks), , deflections, decoys, sacrifices, underminings, overloadings, and interferences. Simple one-move or two-move tactical actions—threats, exchanges of , and double attacks—can be combined into longer sequences of tactical maneuvers that are often forced from the point of view of one or both players. A forced variation that involves a sacrifice and usually results in a tangible gain is called a combination. Brilliant combinations, such as those in the Immortal Game, are considered beautiful and are admired by chess lovers.
A common type of chess exercise, aimed at developing players' tactical skills, is a position where a combination is available and the challenge is to find it. Such positions are usually handcrafted, taken from actual games or from analysis of actual games. Solutions usually result in checkmate, decisive advantage, or successful defense. Tactical exercises are commonly found in instructional books, chess magazines, newspaper chess columns, and internet chess sites.
Sequences of opening moves are referred to as openings and are catalogued in reference works, such as the Encyclopaedia of Chess Openings. There are thousands of openings, though only a small fraction of them are commonly played; variations of openings may also be given names. Openings vary widely in character from quiet (for example, the Réti Opening) to aggressive play (like the Latvian Gambit). In some opening lines, the exact sequence considered best for both sides has been worked out to more than 30 moves.
The fundamental strategic aims of most openings are similar:
Most players and Chess theory consider that White, by virtue of the initiative granted from moving first, begins the game with a small advantage. Black usually strives to neutralize White's advantage and achieve , or to develop in an unbalanced position.
Specific plans or strategic themes will often arise from particular groups of openings that result in a specific type of pawn structure. An example is the minority attack, which is the attack of queenside pawns against an opponent who has more pawns on the queenside. The study of openings is therefore connected to the preparation of plans that are typical of the resulting middlegames.
Another important strategic question in the middlegame is whether and how to reduce material and transition into an endgame (i.e. ). Minor material advantages can generally be transformed into victory only in an endgame, and therefore the stronger side must choose an appropriate way to achieve an ending. Not every reduction of material is good for this purpose; for example, if one side keeps a light-squared bishop and the opponent has a dark-squared one, the transformation into a bishops and pawns ending is usually advantageous for the weaker side only, because an endgame with bishops on opposite colors is likely to be a draw, even with an advantage of a pawn, or sometimes even with a two-pawn advantage.
Endgames can be classified according to the type of pieces remaining on the board. Basic checkmates are positions in which one side has only a king and the other side has one or two pieces and can checkmate the opposing king, with the pieces working together with their king. For example, king and pawn endgames involve only kings and pawns on one or both sides, and the task of the stronger side is to promote one of the pawns. Other more complicated endings are classified according to pieces on the board other than kings, such as "rook and pawn versus rook" endgames.
These are commonly referred to as "two-movers", "three-movers", or "more-movers". "Many-movers" (also known as "long-range problems") of over 100 moves have been composed, the current record standing at over 200; these usually require repetitions of the same manoeuvre in order to produce a repeated zugzwang and force detrimental pawn advances.
Directmates usually consist of positions unlikely to occur in an actual game, and are intended to illustrate a particular , usually requiring a surprising or counterintuitive move. Themes associated with chess problems occasionally appear in actual games, when they are referred to as "problem-like" moves.
Other common types of problems include:
The above type of problems are usually considered orthodox, in the sense that the standard rules of chess are observed.
Fairy chess problems, also called heterodox problems, involve altered rules, such as the use of unconventional pieces or boards, or stipulations that contradict the standard rules of chess such as or .
Endgame study are usually considered distinct from problems, although there is some overlap. In a study, the stipulation is that White to play must win or draw, without specifying any particular number of moves. The majority of studies are Chess endgame positions, with varying degrees of realism or practical application.
Tournaments for composition and solving of chess problems and studies are organized by the World Federation for Chess Composition (WFCC), which works cooperatively with but independent of FIDE. The WFCC awards titles for composing and solving chess problems.
The term "match" refers not to an individual game, but to either a series of games between two players, or a team competition in which each player of one team plays one game against a player of the other team.
FIDE's most visible activity is organizing the World Chess Championship, a role it assumed in 1948. The current World Champion is Gukesh Dommaraju of India. The reigning Women's World Champion is Ju Wenjun from China.
Other competitions for individuals include the World Junior Chess Championship, the European Individual Chess Championship, the tournaments for the World Championship qualification cycle, and the various national championships. Invitation-only tournaments regularly attract the world's strongest players. Examples include Spain's Linares event, Monte Carlo's Melody Amber tournament, the Dortmund Sparkassen meeting, Sofia's M-tel Masters, and Wijk aan Zee's Tata Steel tournament.
Regular team chess events include the Chess Olympiad and the European Team Chess Championship.
The World Chess Solving Championship and World Correspondence Chess Championship include both team and individual events. These are held independently of FIDE by, respectively, the World Federation for Chess Composition (WFCC) and the International Correspondence Chess Federation (ICCF).
Players may be awarded lifetime titles by FIDE:
The above titles are known as "open" titles, obtainable by both men and women. There are also separate women-only titles: Woman Grandmaster (WGM), Woman International Master (WIM), Woman FIDE Master (WFM) and Woman Candidate Master (WCM). These require a performance level approximately 200 rating points below their respective open titles. The continued existence of women-only titles has been debated; critics, including former world championship challenger Judit Polgár, have argued that separate titles are unnecessary and reinforce gender distinctions rather than competitive standards. Beginning with Nona Gaprindashvili in 1978, a number of women have earned the open GM title: 40 .Current FIDE lists of top players with their titles are online at
FIDE also awards titles for arbiters and trainers. International titles are also awarded to composers and solvers of chess problems and to correspondence chess players (by the International Correspondence Chess Federation). National chess organizations may also award titles.
The oldest known chess manual was in Arabic and dates to about 840, written by al-Adli ar-Rumi (800–870), a renowned Arab chess player, titled Kitab ash-shatranj (The Book of Chess). This is a lost manuscript, but is referenced in later works. Here also, al-Adli attributes the origins of Persian chess to India, along with the eighth-century collection of fables Kalīla wa-Dimna. By the 20th century, a substantial consensus developed regarding chess's origins in northwest India in the early seventh century. More recently, this consensus has been the subject of further scrutiny.
The early forms of chess in India were known as chaturaṅga (), literally "four divisions" ofinfantry, cavalry, war elephant, and by pieces that would later evolve into the modern pawn, knight, bishop, and rook, respectively. Chaturanga was played on an 8×8 uncheckered board, called ashtāpada. Thence it spread eastward and westward along the Silk Road. The earliest evidence of chess is found in nearby Sasanian Persia around 600 A.D., where the game came to be known by the name chatrang (). Chatrang was taken up by the Muslim world after the Islamic conquest of Persia (633–51), where it was then named shatranj (; ), with the pieces largely retaining their Persian names. In Spanish, "shatranj" was rendered as ajedrez ("al-shatranj"), in Portuguese as xadrez, and in Greek language as ζατρίκιον ( zatrikion, which comes directly from the Persian chatrang), but in the rest of Europe it was replaced by versions of the Persian shāh ("king"), from which the English words "check" and "chess" descend. The word "checkmate" is derived from the Persian shāh māt ("the king is dead").
Xiangqi is the form of chess best known in China. The eastern migration of chess, into China and Southeast Asia, has even less documentation than its migration west, making it largely conjectured. The word xiàngqí (象棋) was used in China to refer to a game from 569 A.D. at the latest, but it has not been proven that this game was directly related to chess.Peter Banaschak, Facts on the origin of Chinese chess (Xiangqi), 4th Symposium of the Initiative Gruppe Königstein, Wiesbaden, August 1997
The first reference to Chinese chess appears in a book entitled Xuánguaì Lù (玄怪錄; "Record of the Mysterious and Strange"), dating to about 800. A minority view holds that Western chess arose from xiàngqí or one of its predecessors. Chess historians Jean-Louis Cazaux and Rick Knowlton contend that xiangqi's intrinsic characteristics make it easier to construct an evolutionary path from China to India/Persia than the opposite direction. (2026). 9780786494279, McFarland. ISBN 9780786494279
The oldest archaeological chess artifactsivory pieceswere excavated in ancient Afrasiab, today's Samarkand, in Uzbekistan, Central Asia, and date to about 760, with some of them possibly being older. Remarkably, almost all findings of the oldest pieces come from along the Silk Road, from the former regions of the Tarim Basin (today's Xinjiang in China), Transoxiana, Sogdiana, Bactria, Gandhara, to Iran on one end and to India through Kashmir on the other.
The game reached Western Europe and Russia via at least three routes, the earliest being in the ninth century. By the year 1000, it had spread throughout both the Al Andalus and Latin Europe. A Latin poem called Versus de scachis ("Verses on Chess") dated to the late 10th century, has been preserved at Einsiedeln Abbey in Switzerland.
Around 1200, the rules of shatranj started to be modified in Europe, culminating, several major changes later, in the emergence of modern chess practically as it is known today. A major change was the modern piece movement rules, which began to appear in intellectual circles in Valencia, Spain, around 1475, which established the foundations and brought it very close to current chess. These new rules then were quickly adopted in Italy and Southern France before diffusing into the rest of Europe. Pawns gained the ability to advance two squares on their first move, while bishops and queens acquired their modern movement powers. The queen replaced the earlier vizier chess piece toward the end of the 10th century and by the 15th century had become the most powerful piece; in light of that, modern chess was often referred to at the time as "Queen's Chess" or "Mad Queen Chess". Castling, derived from the "king's leap", usually in combination with a pawn or rook move to bring the king to safety, was introduced. These new rules quickly spread throughout Western Europe.
Writings about chess theory began to appear in the late 15th century. An anonymous treatise on chess of 1490 with the first part containing some openings and the second 30 endgames is deposited in the library of the University of Göttingen. The book El Libro dels jochs partitis dels schachs en nombre de 100 was written by Francesc Vicent in Segorbe in 1495, but no copy of this work has survived. The Repetición de Amores y Arte de Ajedrez ( Repetition of Love and the Art of Playing Chess) by Spanish people churchman Luis Ramírez de Lucena was published in Salamanca in 1497. Lucena and later masters like Portuguese Pedro Damiano, Italians Giovanni Leonardo Di Bona, Giulio Cesare Polerio and Gioachino Greco, and Spanish bishop Ruy López de Segura developed elements of opening theory and started to analyze simple endgames.
At the same time, the Romanticism intellectual movement had had a far-reaching impact on chess, with aesthetics and tactical beauty being held in higher regard than objective soundness and strategic planning. As a result, virtually all games began with the Open Game, and it was considered unsportsmanlike to decline gambits that invited tactical play such as the King's Gambit and the Evans Gambit. This chess philosophy is known as Romantic chess, and its sharp, tactical style of play was predominant until the late 19th century.
The rules concerning stalemate were finalized in the early 19th century. Also in the 19th century, the convention that White moves first was established (formerly either White or Black could move first). Finally, the rules around castling and en passant captures were standardized—variations in these rules persisted in Italy until the late 19th century. The resulting standard game is sometimes referred to as Western chess or international chess, particularly in Asia where other games of the chess family such as xiangqi are prevalent. Since the 19th century, the only rule changes, such as the establishment of the correct procedure for claiming a draw by repetition, have been technical in nature.
As the 19th century progressed, chess organization developed quickly. Many , chess books, and chess journals appeared. There were correspondence matches between cities; for example, the London Chess Club played against the Edinburgh Chess Club in 1824. Chess problems became a regular part of 19th-century newspapers; Bernhard Horwitz, Josef Kling, and Samuel Loyd composed some of the most influential problems. In 1843, von der Lasa published his and Bilguer's Handbuch des Schachspiels ( Handbook of Chess), the first comprehensive manual of chess theory.
The first modern chess tournament was organized by Howard Staunton, a leading English chess player, and was held in London in 1851. It was won by the German Adolf Anderssen, who was hailed as the leading chess master. His energetic attacking style was Romantic chess. Sparkling games like Anderssen's Immortal Game and Evergreen Game or Paul Morphy "Opera Game" were regarded as the highest possible summit of the art of chess. Deeper insight into the nature of chess came with the American Paul Morphy, an extraordinary chess prodigy. Morphy won against all important competitors (except Staunton, who refused to play), including Anderssen, during his short chess career between 1857 and 1863.
After the end of the 19th century, the number of master tournaments and matches held annually quickly grew. The first Chess Olympiad was held in Paris in 1924, and FIDE was founded initially for the purpose of organizing that event. In 1927, the Women's World Chess Championship was established; the first to hold the title was Czech-English master Vera Menchik.
A prodigy from Cuba, José Raúl Capablanca, known for his skill in endgames, won the World Championship from Lasker in 1921. Capablanca was undefeated in tournament play for eight years, from 1916 to 1924. His successor (1927) was the Russian-French Alexander Alekhine, a strong attacking player who died as the world champion in 1946. Alekhine briefly lost the title to Dutch player Max Euwe in 1935 and regained it two years later.
In the interwar period, chess was revolutionized by the new theoretical school of so-called hypermodernists like Aron Nimzowitsch and Richard Réti. They advocated controlling the of the board with distant pieces rather than with pawns, thus inviting opponents to occupy the center with pawns, which become objects of attack. Among the innovations popularized by hypermodernists was the fianchetto: the development of bishops away from, rather than towards, the center, onto the b- and g-files.
Botvinnik started an era of Soviet Union dominance in the chess world, which mainly through the Soviet government's politically inspired efforts to demonstrate intellectual superiority over the West stood almost uninterrupted for more than a half-century. Until the dissolution of the Soviet Union, there was only one non-Soviet champion, American Bobby Fischer (champion 1972–1975). Botvinnik also revolutionized opening theory. Previously, Black strove for equality, attempting to neutralize White's first-move advantage. As Black, Botvinnik strove for the initiative from the beginning. In the previous informal system of World Championships, the current champion decided which challenger he would play for the title and the challenger was forced to seek sponsors for the match. FIDE set up a new system of qualifying tournaments and matches. The world's strongest players were seeded into Interzonal tournaments, where they were joined by players who had qualified from Zonal tournaments (often national or regional championships). The leading finishers in these Interzonals would go through the "Candidates" stage, which was initially a tournament, and later a series of knockout matches. The winner of the Candidates would then play the reigning champion for the title. A champion defeated in a match had a right to play a rematch a year later. This system operated on a three-year cycle. Botvinnik participated in championship matches over a period of fifteen years. He won the world championship tournament in 1948 and retained the title in tied matches in 1951 and 1954. In 1957, he lost to Vasily Smyslov, but regained the title in a rematch in 1958. In 1960, he lost the title to the 23-year-old Latvian prodigy Mikhail Tal, an accomplished Chess tactics and attacking player who is widely regarded as one of the most creative players ever, hence his nickname "the magician from Riga". Botvinnik again regained the title in a rematch in 1961.
Following the 1961 event, FIDE abolished the automatic right of a deposed champion to a rematch, and the next champion, Armenian Tigran Petrosian, a player renowned for his defensive and positional skills, held the title for two cycles, 1963–1969. His successor, Boris Spassky from Russia (champion 1969–1972), won games in both positional and sharp tactical style.; The next championship, the so-called Match of the Century, saw the first non-Soviet challenger since World War II, American Bobby Fischer. Fischer defeated his opponents in the Candidates matches by unheard-of margins, and convincingly defeated Spassky for the world championship. The match was followed closely by news media of the day, leading to a surge in popularity for chess; it also held significant political importance at the height of the Cold War, with the match being seen by both sides as a microcosm of the conflict between East and West. In 1975, however, Fischer refused to defend his title against Soviet Anatoly Karpov when he was unable to reach agreement on conditions with FIDE, and Karpov obtained the title by default. Fischer modernized many aspects of chess, especially by extensively preparing openings.
Karpov defended his title twice against Viktor Korchnoi and dominated the 1970s and early 1980s with a string of tournament successes.; In the 1984 World Chess Championship, Karpov faced his toughest challenge to date, the young Garry Kasparov from Baku, Soviet Azerbaijan. The match was aborted in controversial circumstances after 5 months and 48 games with Karpov leading by 5 wins to 3, but evidently exhausted; many commentators believed Kasparov, who had won the last two games, would have won the match had it continued. Kasparov won the 1985 rematch. Kasparov and Karpov contested three further closely fought matches in 1986, 1987 and 1990, Kasparov winning them all. Kasparov became the dominant figure of world chess from the mid-1980s until his retirement from competition in 2005.
The first endgame tablebases, which provided perfect play for relatively simple endgames such as king and rook versus king and bishop, appeared in the late 1970s. This set a precedent to the complete six- and seven-piece tablebases that became available in the 2000s and 2010s respectively.
Some of the earliest , which are collections of chess games searchable by move and position, include Ken Thompson and Joe Condon's king-queen versus king-rook chess database. They were used for testing early chess engines like Belle. It won the ACM North American Computer Chess Championship five times and the 1980 World Computer Chess Championship. The first commercial chess database was introduced by the German company ChessBase in 1987. Databases containing millions of chess games have since had a profound effect on opening theory and other areas of chess research.
Digital chess clocks were invented in 1973, though they did not become commonplace until the 1990s. Digital clocks allow for time controls involving increments and delays.
Computer chess has also seen major advances. By the 1990s, chess engines could consistently defeat most amateurs, and in 1997 Deep Blue defeated World Champion Garry Kasparov in a six-game match, starting an era of computer dominance at the highest level of chess. In the 2010s, engines significantly stronger than even the best human players became accessible for free on a number of PC and Mobile phone platforms, and free engine analysis became a commonplace feature on internet chess servers. An adverse effect of the easy availability of engine analysis on hand-held devices and personal computers has been the rise of Chess cheating, which has grown to be a major concern in both over-the-board and online chess. In 2017, AlphaZero—a neural network also capable of playing shogi and Go—was introduced. Since then, many chess engines based on neural network evaluation have been written, the best of which have surpassed the traditional "brute-force" engines. AlphaZero also introduced many novel ideas and ways of playing the game, which affected the style of play at the top level.
As endgame tablebases developed, they began to provide perfect play in endgame positions in which the Game theory outcome was previously unknown, such as positions with king, queen and pawn against king and queen. In 1991, Lewis Stiller published a tablebase for select six-piece endgames,See also: and by 2005, following the publication of Eugene Nalimov tablebases, all six-piece endgame positions were solved. In 2012, Lomonosov tablebases were published which solved all seven-piece endgame positions. Use of tablebases enhances the performance of chess engines by providing definitive results in some branches of analysis.
Previously, preparation at the professional level required an extensive chess library and several subscriptions to publications such as Chess Informant to keep up with opening developments and study opponents' games. Today, preparation at the professional level involves the use of databases containing millions of games, and engines to analyze different opening variations and prepare novelties. A number of online learning resources are also available for players of all levels, such as online courses, tactics trainers, and video lessons.
Since the late 1990s, it has been possible to follow major international chess events online, the players' moves being relayed in real time. Sensory boards have been developed to enable automatic transmission of moves. Chess players will frequently run engines while watching these games, allowing them to quickly identify mistakes by the players and spot tactical opportunities. While in the past the moves have been relayed live, today chess organizers will often impose a half-hour delay as an anti-cheating measure. Technological progress made in the 1990s and the 21st century has influenced the way that chess is studied at all levels, as well as the state of chess as a spectator sport. In the mid-to-late 2010s, and especially following the 2020 online boom, it became commonplace for supergrandmasters, such as Hikaru Nakamura and Magnus Carlsen, to livestream chess content on platforms such as Twitch. Also following the boom, online chess started being viewed as an esport, with esport teams signing chess players for the first time in 2020. In 2025, the number of esport teams signing chess players rose considerably, after chess was added to Saudi Arabia's Esports World Cup.
Organized chess even for young children has become common. FIDE holds world championships for age levels down to 8 years old. The largest tournaments, in number of players, are those held for children.
The World Chess Championship 2006, in which Kramnik beat the FIDE World Champion Veselin Topalov, reunified the titles and made Kramnik the undisputed World Chess Champion. In September 2007, he lost the title to Viswanathan Anand of India. Anand defended his title in the revenge match of 2008, 2010 and 2012. Magnus Carlsen defeated Anand in 2013, defending his title in 2014, 2016, 2018, and 2021, whereafter he announced that he would not defend his title a fifth time. The 2023 championship was played between the winner and runner-up of the Candidates Tournament 2022: Ian Nepomniachtchi of Russia and Ding Liren of China. Ding beat Nepomniachtchi, making him the world champion. In 2024, Gukesh Dommaraju of India beat Ding. Carlsen has however remained the world's highest-rated player.
Some of the elaborate chess sets used by the aristocracy at least partially survive, such as the Lewis chessmen.
Chess was often used as a basis of sermons on morality. An example is Liber de moribus hominum et officiis nobilium sive super ludo scacchorum ('Book of the customs of men and the duties of nobles or the Book of Chess'), written by an Italian Dominican friar Jacobus de Cessolis . This book was one of the most popular of the Middle Ages. The work was translated into many other languages (the first printed edition was published at Utrecht in 1473) and was the basis for William Caxton's The Game and Playe of the Chesse (1474), one of the first books printed in English. Different chess pieces were used as metaphors for different classes of people, and human duties were derived from the rules of the game or from visual properties of the chess pieces:
Known in the circles of clerics, students, and merchants, chess entered into the popular culture of the Middle Ages. An example is the 209th song of Carmina Burana from the 13th century, which starts with the names of chess pieces, Roch, pedites, regina... The game of chess, at times, has been discouraged by various religious authorities in Middle Ages: Jewish, Catholic and Orthodox. Some Muslim authorities prohibited it even recently, for example Ruhollah Khomeini in 1979 and Abdul-Aziz ash-Sheikh even later.
During the Age of Enlightenment, chess was viewed as a means of self-improvement. Benjamin Franklin, in his article "The Morals of Chess" (1786), wrote:
Chess was occasionally criticized in the 19th century as a waste of time.
Chess is taught to children in schools around the world today. Many schools host chess clubs, and there are many scholastic tournaments specifically for children. Tournaments are held regularly in many countries, hosted by organizations such as the United States Chess Federation and the National Scholastic Chess Foundation.
Chess is many times depicted in the arts; significant works where chess plays a key role range from Thomas Middleton's A Game at Chess to Through the Looking-Glass by Lewis Carroll, to Vladimir Nabokov's The Defense, to The Royal Game by Stefan Zweig. Chess has also featured in film classics such as Ingmar Bergman's The Seventh Seal, Satyajit Ray's The Chess Players, and Powell and Pressburger's A Matter of Life and Death.
Chess is also present in contemporary popular culture. For example, the characters in Star Trek play a futuristic version of the game called "Federation Tri-Dimensional Chess", and "Wizard's Chess" is played in J.K. Rowling's Harry Potter.
The number of legal positions in chess is estimated to be with a 95% confidence level, with a game-tree complexity of approximately 10123. The game-tree complexity of chess was first calculated by Claude Shannon as 10120, a number known as the Shannon number. An average position typically has thirty to forty possible moves, but there may be as few as zero (in the case of checkmate or stalemate) or (in a constructed position) as many as 218.
In 1913, Ernst Zermelo used chess as a basis for his theory of game strategies, which is considered one of the predecessors of game theory.Zermelo, Ernst (1913), Uber eine Anwendung der Mengenlehre auf die Theorie des Schachspiels, Proceedings of the Fifth International Congress of Mathematicians 2, 501–04. Cited from Eichhorn, Christoph: Der Beginn der Formalen Spieltheorie: Zermelo (1913), Uni-Muenchen.de . Retrieved 23 March 2007. Zermelo's theorem states that it is possible to Solving chess, i.e. to determine with certainty the outcome of a perfectly played game (either White can force a win, or Black can force a win, or both sides can force at least a draw). With 1043 legal positions in chess, however, it will take an impossibly long time to compute a perfect strategy with any feasible technology. (1977). 9780824722586, CRC Press. ISBN 9780824722586
Correspondence chess has been historically suspected of being a potential steganographic medium. Melville Davisson Post documented a chess problem that was used to create a pictorial cipher during World War I. During World War II, extensive postal censorship was imposed on military personnel from the United States and Canada that made playing correspondence chess impossible, arising from suspicion that chess could be used to send secret messages to the enemies.
More recent research has focused on chess as mental training; the respective roles of knowledge and look-ahead search; brain imaging studies of chess masters and novices; blindfold chess; the role of personality and intelligence in chess skill; gender differences; and computational models of chess expertise. The role of practice and talent in the development of chess and other domains of expertise has led to much empirical investigation. Ericsson and colleagues have argued that deliberate practice is sufficient for reaching high levels of expertise in chess. Recent research, however, fails to replicate their results and indicates that factors other than practice are also important.Gobet, F. & Chassy, P. (in press). Journal of Biosocial Science.
Gobet, F. & Campitelli, G. (2007). Developmental Psychology, 43, 159–72. Both retrieved 2007-07-15.
For example, Fernand Gobet and colleagues have shown that stronger players started playing chess at a young age and that experts born in the Northern Hemisphere are more likely to have been born in late winter and early spring. Compared to the general population, chess players are more likely to be non-right-handed, though they found no correlation between handedness and skill.
A relationship between chess skill and intelligence has long been discussed in scientific literature as well as in popular culture. Academic studies that investigate the relationship date back at least to 1927.Djakow, I. N., Petrowski, N. W., & Rudik, P. A. (1927).
Psychologie des schachspiels.
The Association for Computing Machinery (ACM) held the first major chess tournament for computers, the North American Computer Chess Championship, in September 1970. CHESS 3.0, a chess program from Northwestern University, won the championship. The first World Computer Chess Championship, held in 1974, was won by the Soviet program Kaissa. At first considered only a curiosity, the best chess engine have become extremely strong. In 1997, a computer won a chess match using classical time controls against a reigning World Champion for the first time: IBM Deep Blue beat Garry Kasparov 3½–2½ (it scored two wins, one loss, and three draws). Deep Blue – Kasparov Match . . Retrieved 30 November 2006. There was some controversy over the match, and human–computer matches were relatively close over the next few years, until convincing computer victories in 2005 and in 2006.
In 2009, a mobile phone won a category 6 tournament with a performance rating of 2898: chess engine Hiarcs 13 running on the mobile phone HTC Touch HD won the Copa Mercosur tournament with nine wins and one draw. The best chess programs are now able to consistently beat the strongest human players, to the extent that human–computer matches no longer attract interest from chess players or the media. While the World Computer Chess Championship still exists, the Top Chess Engine Championship (TCEC) is widely regarded as the unofficial world championship for chess chess engine. The current champion is Stockfish.
With huge databases of past games and high analytical ability, computers can help players to learn chess and prepare for matches. Internet Chess Servers allow people to find and play opponents worldwide. The presence of computers and modern communication tools have raised concerns regarding cheating during games.
They include modern variations employing different rules (e.g. losing chess and Chess960), different armies (e.g. Dunsany's chess), Fairy piece (e.g. Knighted chess and Falcon–hunter chess), and different board geometries (e.g. hexagonal chess and infinite chess). In the context of chess variants, chess is commonly referred to as orthodox chess, orthochess, and classic chess.
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