Computer chess includes both hardware (dedicated computers) and software capable of playing chess . Computer chess provides opportunities for players to practice even in the absence of human opponents, and also provides opportunities for analysis, entertainment and training. Computer chess applications that play at the level of a chess grandmaster or higher are available on hardware from supercomputers to smart phones . Standalone chess-playing machines are also available. Stockfish , Leela Chess Zero , GNU Chess , Fruit , and other free open source applications are available for various platforms.
95-478: The Blind Chess Olympiad is an international chess competition for the blind in which teams from all over the world compete against each other. The event takes place every four years, and is sponsored by the International Braille Chess Association . The Blind Chess Olympiad is the largest sporting event in the international field of chess for the visually impaired. The forerunner to
190-566: A command-line interface which calculates which moves are strongest in a position) or a graphical user interface (GUI) which provides the player with a chessboard they can see, and pieces that can be moved. Engines communicate their moves to the GUI using a protocol such as the Chess Engine Communication Protocol (CECP) or Universal Chess Interface (UCI). By dividing chess programs into these two pieces, developers can write only
285-541: A parallel search algorithm as calculations on the GPU are inherently parallel. The minimax and alpha-beta pruning algorithms used in computer chess are inherently serial algorithms, so would not work well with batching on the GPU. On the other hand, MCTS is a good alternative, because the random sampling used in Monte Carlo tree search lends itself well to parallel computing, and is why nearly all engines which support calculations on
380-465: A built in mechanism for reducing the Elo rating of the engine (via UCI's uci_limitstrength and uci_elo parameters). Some versions of Fritz have a Handicap and Fun mode for limiting the current engine or changing the percentage of mistakes it makes or changing its style. Fritz also has a Friend Mode where during the game it tries to match the level of the player. Chess databases allow users to search through
475-435: A certain maximum search depth or the program determines that a final "leaf" position has been reached (e.g. checkmate). One particular type of search algorithm used in computer chess are minimax search algorithms, where at each ply the "best" move by the player is selected; one player is trying to maximize the score, the other to minimize it. By this alternating process, one particular terminal node whose evaluation represents
570-606: A chess engine connected to a GUI, such as Winboard or Chessbase . Playing strength, time controls, and other performance-related settings are adjustable from the GUI. Most GUIs also allow the player to set up and to edit positions, to reverse moves, to offer and to accept draws (and resign), to request and to receive move recommendations, and to show the engine's analysis as the game progresses. There are thousands of chess engines such as Sargon , IPPOLIT , Stockfish , Crafty , Fruit , Leela Chess Zero and GNU Chess which can be downloaded (or source code otherwise obtained) from
665-587: A chess-playing computer system must decide on a number of fundamental implementation issues. These include: Adriaan de Groot interviewed a number of chess players of varying strengths, and concluded that both masters and beginners look at around forty to fifty positions before deciding which move to play. What makes the former much better players is that they use pattern recognition skills built from experience. This enables them to examine some lines in much greater depth than others by simply not considering moves they can assume to be poor. More evidence for this being
760-419: A computer must examine a quadrillion possibilities to look ahead ten plies (five full moves); one that could examine a million positions a second would require more than 30 years. The earliest attempts at procedural representations of playing chess predated the digital electronic age, but it was the stored program digital computer that gave scope to calculating such complexity. Claude Shannon, in 1949, laid out
855-530: A current computer program could ever win a single game against a master player would be for the master, perhaps in a drunken stupor while playing 50 games simultaneously, to commit some once-in-a-year blunder". In the late 1970s chess programs suddenly began defeating highly skilled human players. The year of Hearst's statement, Northwestern University 's Chess 4.5 at the Paul Masson American Chess Championship's Class B level became
950-408: A dark square. This may be remembered by the phrases "light on the right" and "queen on her own color". In formal competition, the piece colors for every matchup are allocated to players by the organizers. In informal games, colors are decided either by mutual agreement, or randomly, for example by a coin toss, or by one player concealing a white pawn in one hand and a black pawn in the other and having
1045-568: A game can end in a draw . The recorded history of chess goes back at least to the emergence of a similar game, chaturanga , in seventh-century India . After its introduction in Persia , it spread to the Arab world and then to Europe. The rules of chess as they are known today emerged in Europe at the end of the 15th century, with standardization and universal acceptance by the end of the 19th century. Today, chess
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#17330849079971140-499: A large library of historical games, analyze them, check statistics, and formulate an opening repertoire. Chessbase (for PC) is a common program for these purposes amongst professional players, but there are alternatives such as Shane's Chess Information Database (Scid) for Windows, Mac or Linux, Chess Assistant for PC, Gerhard Kalab's Chess PGN Master for Android or Giordano Vicoli's Chess-Studio for iOS. Programs such as Playchess allow players to play against one another over
1235-441: A large number of training apps such as CT-ART and its Chess King line based on tutorials by GM Alexander Kalinin and Maxim Blokh. There is also software for handling chess problems . After discovering refutation screening—the application of alpha–beta pruning to optimizing move evaluation—in 1957, a team at Carnegie Mellon University predicted that a computer would defeat the world human champion by 1967. It did not anticipate
1330-420: A list ("piece list"), collections of bit-sets for piece locations (" bitboards "), and huffman coded positions for compact long-term storage. Computer chess programs consider chess moves as a game tree . In theory, they examine all moves, then all counter-moves to those moves, then all moves countering them, and so on, where each individual move by one player is called a " ply ". This evaluation continues until
1425-470: A long-term advantage the computer is not able to see in its game tree search. Fritz, however, won game 5 after a severe blunder by Kramnik. Game 6 was described by the tournament commentators as "spectacular". Kramnik, in a better position in the early middlegame , tried a piece sacrifice to achieve a strong tactical attack, a strategy known to be highly risky against computers who are at their strongest defending against such attacks. True to form, Fritz found
1520-607: A match when it defeated Garry Kasparov . Today's chess engines are significantly stronger than the best human players and have deeply influenced the development of chess theory; however, chess is not a solved game . The rules of chess are published by FIDE (Fédération Internationale des Échecs; "International Chess Federation"), chess's world governing body, in its Handbook . Rules published by national governing bodies , or by unaffiliated chess organizations, commercial publishers, etc., may differ in some details. FIDE's rules were most recently revised in 2023. Chess sets come in
1615-399: A mate in one ), and drew the next four. In the final game, in an attempt to draw the match, Kramnik played the more aggressive Sicilian Defence and was crushed. There was speculation that interest in human–computer chess competition would plummet as a result of the 2006 Kramnik-Deep Fritz match. According to Newborn, for example, "the science is done". Human–computer chess matches showed
1710-409: A microprocessor running a software chess program, but sometimes as a specialized hardware machine), software programs running on standard PCs, web sites, and apps for mobile devices. Programs run on everything from super-computers to smartphones. Hardware requirements for programs are minimal; the apps are no larger than a few megabytes on disk, use a few megabytes of memory (but can use much more, if it
1805-462: A number of common de facto standards. Nearly all of today's programs can read and write game moves as Portable Game Notation (PGN), and can read and write individual positions as Forsyth–Edwards Notation (FEN). Older chess programs often only understood long algebraic notation , but today users expect chess programs to understand standard algebraic chess notation . Starting in the late 1990s, programmers began to develop separately engines (with
1900-540: A player's rating is determined – the advantage was not so clear. In the early 2000s, commercially available programs such as Junior and Fritz were able to draw matches against former world champion Garry Kasparov and classical world champion Vladimir Kramnik . In October 2002, Vladimir Kramnik and Deep Fritz competed in the eight-game Brains in Bahrain match, which ended in a draw. Kramnik won games 2 and 3 by "conventional" anti-computer tactics – play conservatively for
1995-537: A return match. A documentary mainly about the confrontation was made in 2003, titled Game Over: Kasparov and the Machine . With increasing processing power and improved evaluation functions, chess programs running on commercially available workstations began to rival top-flight players. In 1998, Rebel 10 defeated Viswanathan Anand , who at the time was ranked second in the world, by a score of 5–3. However, most of those games were not played at normal time controls. Out of
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#17330849079972090-644: A role it assumed in 1948. The current World Champion is Ding Liren of China. 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
2185-511: 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. Chess's international governing body is usually known by its French acronym FIDE (pronounced FEE-day) ( French : Fédération internationale des échecs), or International Chess Federation. FIDE's membership consists of the national chess organizations of over 180 countries; there are also several associate members, including various supra-national organizations,
2280-505: A simple trap known as the Scholar's mate (see animated diagram) can be recorded: 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 publications for universal readability regardless of language. Portable Game Notation (PGN)
2375-418: A six-game match (though Adams' preparation was far less thorough than Kramnik's for the 2002 series). In November–December 2006, World Champion Vladimir Kramnik played Deep Fritz. This time the computer won; the match ended 2–4. Kramnik was able to view the computer's opening book. In the first five games Kramnik steered the game into a typical "anti-computer" positional contest. He lost one game ( overlooking
2470-647: A system of defining upper and lower bounds on possible search results and searching until the bounds coincided, is typically used to reduce the search space of the program. In addition, various selective search heuristics, such as quiescence search , forward pruning, search extensions and search reductions, are also used as well. These heuristics are triggered based on certain conditions in an attempt to weed out obviously bad moves (history moves) or to investigate interesting nodes (e.g. check extensions, passed pawns on seventh rank , etc.). These selective search heuristics have to be used very carefully however. Over extend and
2565-462: A watertight defense and Kramnik's attack petered out leaving him in a bad position. Kramnik resigned the game, believing the position lost. However, post-game human and computer analysis has shown that the Fritz program was unlikely to have been able to force a win and Kramnik effectively sacrificed a drawn position. The final two games were draws. Given the circumstances, most commentators still rate Kramnik
2660-476: A wide variety of styles. The Staunton pattern is the most common, and is usually required for competition. Chess pieces are divided into two sets, usually light and dark colored, referred to as white and black , regardless of the actual color or design. The players of the sets are referred to as White and Black , respectively. Each set consists of sixteen pieces: one king , one queen , two rooks , two bishops , two knights , and eight pawns . The game
2755-399: Is a text-based file format for recording chess games, based on short form English algebraic notation with a small amount of markup . PGN files (suffix .pgn) can be processed by most chess software, as well as being easily readable by humans. Until about 1980, the majority of English language chess publications used descriptive notation , in which files are identified by the initial letter of
2850-588: Is available), and any processor 300 Mhz or faster is sufficient. Performance will vary modestly with processor speed, but sufficient memory to hold a large transposition table (up to several gigabytes or more) is more important to playing strength than processor speed. Most available commercial chess programs and machines can play at super-grandmaster strength (Elo 2700 or more), and take advantage of multi-core and hyperthreaded computer CPU architectures. Top programs such as Stockfish have surpassed even world champion caliber players. Most chess programs comprise
2945-415: Is compulsory; a player may not skip a turn, even when having to move is detrimental . Each piece has its own way of moving. In the diagrams, crosses mark the squares to which the piece can move if there are no intervening piece(s) of either color (except the knight, which leaps over any intervening pieces). All pieces except the pawn can capture an enemy piece if it is on a square to which they could move if
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3040-423: Is controlled using a chess clock that has 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 . Time controls are also enforced in correspondence chess competitions. A typical time control is 50 days for every 10 moves. Historically, many different notation systems have been used to record chess moves;
3135-732: Is in contrast to supercomputers such as Deep Blue that searched 200 million positions per second. Advanced Chess is a form of chess developed in 1998 by Kasparov where a human plays against another human, and both have access to computers to enhance their strength. The resulting "advanced" player was argued by Kasparov to be stronger than a human or computer alone. This has been proven in numerous occasions, such as at Freestyle Chess events. Players today are inclined to treat chess engines as analysis tools rather than opponents. Chess grandmaster Andrew Soltis stated in 2016 "The computers are just much too good" and that world champion Magnus Carlsen won't play computer chess because "he just loses all
3230-470: Is likely to refute another). The drawback is that transposition tables at deep ply depths can get quite large – tens to hundreds of millions of entries. IBM's Deep Blue transposition table in 1996, for example was 500 million entries. Transposition tables that are too small can result in spending more time searching for non-existent entries due to threshing than the time saved by entries found. Many chess engines use pondering , searching to deeper levels on
3325-399: Is not a permissible response to a check. 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. It is never legal for a player to make a move that puts or leaves the player's own king in check. In casual games, it is common to announce "check" when putting the opponent's king in check, but this
3420-435: Is not currently possible for modern computers due to the game's extremely large number of possible variations . Computer chess was once considered the " Drosophila of AI", the edge of knowledge engineering . The field is now considered a scientifically completed paradigm, and playing chess is a mundane computing activity. Chess machines/programs are available in several different forms: stand-alone chess machines (usually
3515-411: Is not required by the rules of chess and is usually not done in tournaments. Once per game, each king can make a move known as castling . Castling consists of moving the king two squares toward a rook of the same color on the same rank, and then placing the rook on the square that the king crossed. Castling is permissible if the following conditions are met: Castling is still permitted if
3610-536: Is one of the world's most popular games, with millions of players worldwide. Organized chess arose in the 19th century. Chess competition today is governed internationally by FIDE ( Fédération Internationale des Échecs ; the International Chess Federation). The first universally recognized World Chess Champion , Wilhelm Steinitz , claimed his title in 1886; Ding Liren is the current World Champion. A huge body of chess theory has developed since
3705-430: Is played on a chessboard with 64 squares arranged in an 8×8 grid. The players, referred to generically as "White" and "Black" , each control sixteen pieces : one king , one queen , two rooks , two bishops , two knights , and eight pawns . White moves first, followed by Black; then moves alternate. The object of the game is to checkmate (threaten with inescapable capture) the enemy king. There are also several ways
3800-422: Is played on a square board of eight rows (called ranks ) and eight columns (called files ). Although it does not affect game play, by convention the 64 squares alternate in color and are referred to as light and dark squares. Common colors for wooden chessboards are light and dark brown, while vinyl chessboards are commonly buff and green. To start the game, White's pieces are placed on
3895-484: Is recognized in FIDE-sanctioned events; game scores recorded in a different notation system may not be used as evidence in the event of a dispute. Chess is often played casually in public spaces such as parks and town squares. Contemporary chess is an organized sport with structured international and national leagues, tournaments, and congresses . Thousands of chess tournaments, matches, and festivals are held around
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3990-526: Is usually calculated as 1 point for each game won and one-half point for each game drawn. Variations such as "football scoring" (3 points for a win, 1 point for a draw) may be used by tournament organizers, but ratings are always calculated on the basis of standard scoring. A player's score may be reported as total score out of games played (e.g. 5½/8), points for versus points against (e.g. 5½–2½), or by number of wins, losses and draws (e.g. +4−1=3). The term "match" refers not to an individual game, but to either
4085-736: The International Braille Chess Association (IBCA), International Committee of Chess for the Deaf (ICCD), and the International Physically Disabled Chess Association (IPCA). FIDE is recognized as a sports governing body by the International Olympic Committee , but chess has never been part of the Olympic Games . FIDE's most visible activity is organizing the World Chess Championship ,
4180-521: The Internet free of charge. Perhaps the most common type of chess software are programs that simply play chess. A human player makes a move on the board, the AI calculates and plays a subsequent move, and the human and AI alternate turns until the game ends. The chess engine , which calculates the moves, and the graphical user interface (GUI) are sometimes separate programs. Different engines can be connected to
4275-743: The Swedish Chess Computer Association rated computer program Komodo at 3361. Chess engines continue to improve. In 2009, chess engines running on slower hardware have reached the grandmaster level. A mobile phone won a category 6 tournament with a performance rating 2898: chess engine Hiarcs 13 running inside Pocket Fritz 4 on the mobile phone HTC Touch HD won the Copa Mercosur tournament in Buenos Aires , Argentina with 9 wins and 1 draw on August 4–14, 2009. Pocket Fritz 4 searches fewer than 20,000 positions per second. This
4370-491: The vacuum-tube computer age (1950s). The early programs played so poorly that even a beginner could defeat them. Within 40 years, in 1997, chess engines running on super-computers or specialized hardware were capable of defeating even the best human players . By 2006, programs running on desktop PCs had attained the same capability. In 2006, Monty Newborn , Professor of Computer Science at McGill University , declared: "the science has been done". Nevertheless, solving chess
4465-529: The Blind Chess Olympiad the most significant sporting event in the international field of chess for the blind to date. Chess Chess is a board game for two players. It is sometimes called international chess or Western chess to distinguish it from related games such as xiangqi (Chinese chess) and shogi (Japanese chess). Chess is an abstract strategy game that involves no hidden information and no elements of chance . It
4560-667: The Blind Chess Olympiads was a blind chess tournament held in Rheinbreitbach , Germany, in 1958. The winner of the event was Reginald Walter Bonham , who would found the International Braille Chess Association. The first official Blind Chess Olympiad was held in 1961 in Meschede , Germany. Eight teams competed to play 122 games in round-robin format with Team Yugoslavia as the resulting winner. For
4655-428: The GPU use MCTS instead of alpha-beta. Many other optimizations can be used to make chess-playing programs stronger. For example, transposition tables are used to record positions that have been previously evaluated, to save recalculation of them. Refutation tables record key moves that "refute" what appears to be a good move; these are typically tried first in variant positions (since a move that refutes one position
4750-453: The GUI, permitting play against different styles of opponent. Engines often have a simple text command-line interface , while GUIs may offer a variety of piece sets, board styles, or even 3D or animated pieces. Because recent engines are so capable, engines or GUIs may offer some way of handicapping the engine's ability, to improve the odds for a win by the human player. Universal Chess Interface (UCI) engines such Fritz or Rybka may have
4845-499: The Spracklens predicted 15; Ken Thompson predicted more than 20; and others predicted that it would never happen. The most widely held opinion, however, stated that it would occur around the year 2000. In 1989, Levy was defeated by Deep Thought in an exhibition match. Deep Thought, however, was still considerably below World Championship level, as the reigning world champion, Garry Kasparov , demonstrated in two strong wins in 1989. It
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#17330849079974940-487: The average human player". The magazine described SPOC as a "state-of-the-art chess program" for the IBM PC with a "surprisingly high" level of play, and estimated its USCF rating as 1700 (Class B). At the 1982 North American Computer Chess Championship , Monroe Newborn predicted that a chess program could become world champion within five years; tournament director and International Master Michael Valvo predicted ten years;
5035-606: The best computer systems overtaking human chess champions in the late 1990s. For the 40 years prior to that, the trend had been that the best machines gained about 40 points per year in the Elo rating while the best humans only gained roughly 2 points per year. The highest rating obtained by a computer in human competition was Deep Thought's USCF rating of 2551 in 1988 and FIDE no longer accepts human–computer results in their rating lists. Specialized machine-only Elo pools have been created for rating machines, but such numbers, while similar in appearance, are not directly compared. In 2016,
5130-419: The case is the way that good human players find it much easier to recall positions from genuine chess games, breaking them down into a small number of recognizable sub-positions, rather than completely random arrangements of the same pieces. In contrast, poor players have the same level of recall for both. The equivalent of this in computer chess are evaluation functions for leaf evaluation, which correspond to
5225-555: The current position and attempt to execute the best such sequence during play. Such trees are typically quite large, thousands to millions of nodes. The computational speed of modern computers, capable of processing tens of thousands to hundreds of thousands of nodes or more per second, along with extension and reduction heuristics that narrow the tree to mostly relevant nodes, make such an approach effective. The first chess machines capable of playing chess or reduced chess-like games were software programs running on digital computers early in
5320-589: The difficulty of determining the right order to evaluate moves. Researchers worked to improve programs' ability to identify killer heuristics , unusually high-scoring moves to reexamine when evaluating other branches, but into the 1970s most top chess players believed that computers would not soon be able to play at a Master level. In 1968, International Master David Levy made a famous bet that no chess computer would be able to beat him within ten years, and in 1976 Senior Master and professor of psychology Eliot Hearst of Indiana University wrote that "the only way
5415-451: The eight games, four were blitz games (five minutes plus five seconds Fischer delay for each move); these Rebel won 3–1. Two were semi-blitz games (fifteen minutes for each side) that Rebel won as well (1½–½). Finally, two games were played as regular tournament games (forty moves in two hours, one hour sudden death); here it was Anand who won ½–1½. In fast games, computers played better than humans, but at classical time controls – at which
5510-404: 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. For example, one variation of
5605-448: The enemy pawn's two-square advance; otherwise, the right to do so is forfeited. For example, in the animated diagram, the black pawn advances two squares from g7 to g5, and the white pawn on f5 can take it en passant on g6 (but only immediately after the black pawn's advance). When a pawn advances to its eighth rank , as part of the move, it is promoted and must be exchanged for the player's choice of queen, rook, bishop, or knight of
5700-400: The first move by each player, about 200,000 after two moves each, and nearly 120 million after just 3 moves each. So a limited lookahead (search) to some depth, followed by using domain-specific knowledge to evaluate the resulting terminal positions was proposed. A kind of middle-ground position, given good moves by both sides, would result, and its evaluation would inform the player about
5795-423: 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
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#17330849079975890-407: The first rank moves to e2"). For pawns, no letter initial is used; so e4 means "pawn moves to the square e4". If the piece makes 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 used to identify the pawn making the capture, for example, exd5 (pawn on the e-file captures
5985-401: The first to win a human tournament. Levy won his bet in 1978 by beating Chess 4.7 , but it achieved the first computer victory against a Master-class player at the tournament level by winning one of the six games. In 1980, Belle began often defeating Masters. By 1982 two programs played at Master level and three were slightly weaker. The sudden improvement without a theoretical breakthrough
6080-436: The g-file, 5th rank" (that is, to the square g5). Different initials may be used for other languages. In chess literature, figurine algebraic notation (FAN) is frequently used to aid understanding independent of language. To resolve ambiguities, an additional letter or number is added to indicate the file or rank from which the piece moved (e.g. Ngf3 means "knight from the g-file moves to the square f3"; R1e2 means "rook on
6175-533: The game of chess (and other games like checkers): Using "ends-and-means" heuristics a human chess player can intuitively determine optimal outcomes and how to achieve them regardless of the number of moves necessary, but a computer must be systematic in its analysis. Most players agree that looking at least five moves ahead (ten plies ) when necessary is required to play well. Normal tournament rules give each player an average of three minutes per move. On average there are more than 30 legal moves per chess position, so
6270-442: The game of chess, because of its daunting complexity, became the " Drosophila of artificial intelligence (AI)". The procedural resolution of complexity became synonymous with thinking, and early computers, even before the chess automaton era, were popularly referred to as "electronic brains". Several different schema were devised starting in the latter half of the 20th century to represent knowledge and thinking, as applied to playing
6365-409: The game's inception. Aspects of art are found in chess composition , and chess in its turn influenced Western culture and the arts , and has connections with 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 beat a reigning World Champion in
6460-466: The goodness or badness of the moves chosen. Searching and comparing operations on the tree were well suited to computer calculation; the representation of subtle chess knowledge in the evaluation function was not. The early chess programs suffered in both areas: searching the vast tree required computational resources far beyond those available, and what chess knowledge was useful and how it was to be encoded would take decades to discover. The developers of
6555-419: The human players' pattern recognition skills, and the use of machine learning techniques in training them, such as Texel tuning, stochastic gradient descent , and reinforcement learning , which corresponds to building experience in human players. This allows modern programs to examine some lines in much greater depth than others by using forwards pruning and other selective heuristics to simply not consider moves
6650-497: The internet. Chess training programs teach chess. Chessmaster had playthrough tutorials by IM Josh Waitzkin and GM Larry Christiansen . Stefan Meyer-Kahlen offers Shredder Chess Tutor based on the Step coursebooks of Rob Brunia and Cor Van Wijgerden. Former World Champion Magnus Carlsen 's Play Magnus company released a Magnus Trainer app for Android and iOS. Chessbase has Fritz and Chesster for children. Convekta provides
6745-435: The like" much more often than they realized; "in short, computers win primarily through their ability to find and exploit miscalculations in human initiatives". By 1982, microcomputer chess programs could evaluate up to 1,500 moves a second and were as strong as mainframe chess programs of five years earlier, able to defeat a majority of amateur players. While only able to look ahead one or two plies more than at their debut in
6840-469: The mid-1970s, doing so improved their play more than experts expected; seemingly minor improvements "appear to have allowed the crossing of a psychological threshold, after which a rich harvest of human error becomes accessible", New Scientist wrote. While reviewing SPOC in 1984, BYTE wrote that "Computers—mainframes, minis, and micros—tend to play ugly, inelegant chess", but noted Robert Byrne 's statement that "tactically they are freer from error than
6935-414: The opponent choose. White moves first, after which players alternate turns, moving one piece per turn (except for castling , when two pieces are moved). A piece is moved to either an unoccupied square or one occupied by an opponent's piece, which is captured and removed from play. With the sole exception of en passant , all pieces capture by moving to the square that the opponent's piece occupies. Moving
7030-442: The opponent has enough pieces left to deliver checkmate). The duration of a game ranges from long (or "classical") games, which can take up to seven hours (even longer if adjournments are permitted), to bullet chess (under 3 minutes per player for the entire game). Intermediate between these are rapid chess games, lasting between one and two hours per game, a popular time control in amateur weekend tournaments. Time
7125-442: The opponent's time, similar to human beings, to increase their playing strength. Of course, faster hardware and additional memory can improve chess program playing strength. Hyperthreaded architectures can improve performance modestly if the program is running on a single core or a small number of cores. Most modern programs are designed to take advantage of multiple cores to do parallel search. Other programs are designed to run on
7220-427: The piece chosen is indicated after the move (for example, e1=Q or e1Q ). Castling is indicated by the special notations 0-0 (or O-O ) for kingside castling and 0-0-0 (or O-O-O ) for queenside castling. A move that places the opponent's king in check usually has the notation " + " added. There are no specific notations for discovered check or double check . Checkmate can be indicated by " # ". At
7315-443: The piece on d5). Ranks may be omitted if unambiguous, for example, exd (pawn on the e-file captures a piece somewhere on the d-file). A minority of publications use " : " to indicate a capture, and some omit the capture symbol altogether. In its most abbreviated form, exd5 may be rendered simply as ed . An en passant capture may optionally be marked with the notation " e.p. " If a pawn moves to its last rank, achieving promotion,
7410-538: 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 is ICCF numeric notation , recognized by the International Correspondence Chess Federation though its use is in decline. In tournament games, players are normally required to keep a score (record of the game). For this purpose, only algebraic notation
7505-606: The principles of algorithmic solution of chess. In that paper, the game is represented by a "tree", or digital data structure of choices (branches) corresponding to moves. The nodes of the tree were positions on the board resulting from the choices of move. The impossibility of representing an entire game of chess by constructing a tree from first move to last was immediately apparent: there are an average of 36 moves per position in chess and an average game lasts about 35 moves to resignation (60-80 moves if played to checkmate, stalemate, or other draw). There are 400 positions possible after
7600-434: The program assume to be poor through their evaluation function, in the same way that human players do. The only fundamental difference between a computer program and a human in this sense is that a computer program can search much deeper than a human player could, allowing it to search more nodes and bypass the horizon effect to a much greater extent than is possible with human players. Computer chess programs usually support
7695-663: The program wastes too much time looking at uninteresting positions. If too much is pruned or reduced, there is a risk cutting out interesting nodes. Monte Carlo tree search (MCTS) is a heuristic search algorithm which expands the search tree based on random sampling of the search space. A version of Monte Carlo tree search commonly used in computer chess is PUCT, Predictor and Upper Confidence bounds applied to Trees. DeepMind's AlphaZero and Leela Chess Zero uses MCTS instead of minimax. Such engines use batching on graphics processing units in order to calculate their evaluation functions and policy (move selection), and therefore require
7790-429: The required piece is not available (e.g. a second queen) an inverted rook is sometimes used as a substitute, but this is not recognized in FIDE-sanctioned games. A game can be won in the following ways: There are several ways a game can end in a draw : In competition, chess games are played with a time control . If a player's time runs out before the game is completed, the game is automatically lost (provided
7885-402: The rook is under attack, or if the rook crosses an attacked square. When a pawn makes a two-step advance from its starting position and there is an opponent's pawn on a square next to the destination square on an adjacent file, then the opponent's pawn can capture it en passant ("in passing"), moving to the square the pawn passed over. This can be done only on the turn immediately following
7980-407: The same color. Usually, the pawn is chosen to be promoted to a queen, but in some cases, another piece is chosen; this is called underpromotion . In the animated diagram , the pawn on c7 can be advanced to the eighth rank and be promoted. There is no restriction on the piece promoted to, so it is possible to have more pieces of the same type than at the start of the game (e.g., two or more queens). If
8075-420: The searched value of the position will be arrived at. Its value is backed up to the root, and that evaluation becomes the valuation of the position on the board. This search process is called minimax. A naive implementation of the minimax algorithm can only search to a small depth in a practical amount of time, so various methods have been devised to greatly speed the search for good moves. Alpha–beta pruning ,
8170-415: The square were unoccupied. Pieces are generally not permitted to move through squares occupied by pieces of either color, except for the knight and during castling. When a king is under immediate attack, it is said to be in check . A move in response to a check is legal only if it results in a position where the king is no longer in check. There are three ways to counter a check: Castling
8265-452: The standard system today is short-form algebraic notation . In this system, each square is uniquely identified by a set of coordinates, a – h for the files followed by 1 – 8 for the ranks. The usual format is The pieces are identified by their initials. In English, these are K (king), Q (queen), R (rook), B (bishop), and N (knight; N is used to avoid confusion with king). For example, Qg5 means "queen moves to
8360-464: The stronger player in the match. In January 2003, Kasparov played Junior , another chess computer program, in New York City. The match ended 3–3. In November 2003, Kasparov played X3D Fritz . The match ended 2–2. In 2005, Hydra , a dedicated chess computer with custom hardware and sixty-four processors and also winner of the 14th IPCCC in 2005, defeated seventh-ranked Michael Adams 5½–½ in
8455-517: The third Blind Chess Olympiad in 1968, held in Weymouth , England, 20 teams competed. Russia won the event with Yugoslavia in second place. The Polish team arrived by train in the early hours of the morning bringing with them the body of their sighted translator who had died en route (Reference: Organizer, John Graham). By the 2008 13th Blind Chess Olympiad in Heraklion , Crete , 34 teams participated, making
8550-404: The time and there's nothing more depressing than losing without even being in the game." Since the era of mechanical machines that played rook and king endings and electrical machines that played other games like hex in the early years of the 20th century, scientists and theoreticians have sought to develop a procedural representation of how humans learn, remember, think and apply knowledge, and
8645-474: The user interface, or only the engine, without needing to write both parts of the program. (See also chess engine .) Developers have to decide whether to connect the engine to an opening book and/or endgame tablebases or leave this to the GUI. The data structure used to represent each chess position is key to the performance of move generation and position evaluation . Methods include pieces stored in an array ("mailbox" and "0x88"), piece positions stored in
8740-459: The world every year catering to players of all levels. Tournaments with a small number of players may use the round-robin format, in which every player plays one game against every other player. For a large number of players, the Swiss system may be used, in which each player is paired against an opponent who has the same (or as similar as possible) score in each round. In either case, a player's score
8835-947: 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 Championships include both team and individual events; these are held independently of FIDE. Chess-playing machine Computer chess applications, whether implemented in hardware or software, use different strategies than humans to choose their moves: they use heuristic methods to build, search and evaluate trees representing sequences of moves from
8930-539: Was not until a 1996 match with IBM's Deep Blue that Kasparov lost his first game to a computer at tournament time controls in Deep Blue versus Kasparov, 1996, game 1 . This game was, in fact, the first time a reigning world champion had lost to a computer using regular time controls. However, Kasparov regrouped to win three and draw two of the remaining five games of the match, for a convincing victory. In May 1997, an updated version of Deep Blue defeated Kasparov 3½–2½ in
9025-582: Was unexpected, as many did not expect that Belle's ability to examine 100,000 positions a second—about eight plies—would be sufficient. The Spracklens, creators of the successful microcomputer program Sargon , estimated that 90% of the improvement came from faster evaluation speed and only 10% from improved evaluations. New Scientist stated in 1982 that computers "play terrible chess ... clumsy, inefficient, diffuse, and just plain ugly", but humans lost to them by making "horrible blunders, astonishing lapses, incomprehensible oversights, gross miscalculations, and
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