Editing Computer chess (section)

== History ==
=== Pre-computer age ===
[[File:Ajedrecista primero1.JPG|thumb|[[El Ajedrecista]]]]
The idea of creating a chess-playing machine dates back to the eighteenth century.  Around 1769, the chess playing [[automaton]] called [[Mechanical Turk|The Turk]], created by [[Kingdom of Hungary|Hungarian]] inventor [[Wolfgang von Kempelen|Farkas Kempelen]], became famous before being exposed as a hoax. Before the development of [[digital computing]], serious trials based on automata such as [[El Ajedrecista]] of 1912, built by Spanish engineer [[Leonardo Torres Quevedo]], which played a king and rook versus king ending, were too complex and limited to be useful for playing full games of chess. The field of mechanical chess research languished until the advent of the digital computer in the 1950s.

=== Early software age: selective search and Botvinnik ===
Since then, chess enthusiasts and [[computer engineer]]s have built, with increasing degrees of seriousness and success, chess-playing machines and computer programs. One of the few chess grandmasters to devote himself seriously to computer chess was former [[World Chess Champion]] [[Mikhail Botvinnik]], who wrote several works on the subject. Botvinnik's interest in Computer Chess started in the 50s, favouring chess algorithms based on Shannon's selective type B strategy, as discussed along with Max Euwe 1958 in Dutch Television. Working with relatively primitive hardware available in the [[Soviet Union]] in the early 1960s, Botvinnik had no choice but to investigate software move selection techniques; at the time only the most powerful computers could achieve much beyond a three-ply full-width search, and Botvinnik had no such machines.  In 1965 Botvinnik was a consultant to the ITEP team in a US-Soviet computer chess match which won a correspondence chess match against the Kotok-McCarthy-Program led by John McCarthy in 1967.(see [[Kotok-McCarthy]]). Later he advised the team that created the chess program Kaissa at Moscow's Institute of Control Sciences. Botvinnik had his own ideas to model a Chess Master's Mind. After publishing and discussing his early ideas on attack maps and trajectories at Moscow Central Chess Clubin 1966, he found Vladimir Butenko as supporter and collaborator. Butenko first implemented the 15x15 vector attacks board representation on a M-20 computer, determining trajectories. After Botvinnik introduced the concept of Zones in 1970, Butenko refused further cooperation and began to write his own program, dubbed Eureka. In the 70s and 80s, leading a team around Boris Stilman, Alexander Yudin, Alexander Reznitskiy, Michael Tsfasman and Mikhail Chudakov, Botvinnik worked on his own project 'Pioneer' - which was an Artificial Intelligence based chess project. In the 90s, Botvinnik already in his 80s, he worked on the new project 'CC Sapiens'.

=== Later software age: full-width search ===
One developmental milestone occurred when the team from [[Northwestern University]], which was responsible for the [[Chess (Northwestern University)|Chess]] series of programs and won the first three [[Association for Computing Machinery|ACM]] [[World Computer Chess Championship#ACM|Computer Chess Championships]] (1970–72), abandoned type B searching in 1973. The resulting program, Chess 4.0, won that year's championship and its successors went on to come in second in both the 1974 ACM Championship and that year's inaugural [[World Computer Chess Championship]], before winning the ACM Championship again in 1975, 1976 and 1977.  The type A implementation turned out to be just as fast: in the time it used to take to decide which moves were worthy of being searched, it was possible just to search all of them. In fact, Chess 4.0 set the paradigm that was and still is followed essentially by all modern Chess programs today, and that had been successfully started by the Russian ITEP in 1965.

=== Rise of chess machines ===
In 1978, an early rendition of Ken Thompson's hardware chess machine [[Belle (chess machine)|Belle]], entered and won the North American Computer Chess Championship over the dominant Northwestern University Chess 4.7.

=== Microcomputer revolution ===
Technological advances by orders of magnitude in processing power have made the brute force approach far more incisive than was the case in the early years.  The result is that a very solid, tactical AI player aided by some limited positional knowledge built in by the evaluation function and pruning/extension rules began to match the best players in the world. It turned out to produce excellent results, at least in the field of chess, to let computers do what they do best (calculate) rather than coax them into imitating human thought processes and knowledge.  In 1997 [[IBM Deep Blue|Deep Blue]], a brute-force machine capable of examining 500&nbsp;million nodes per second, defeated World Champion Garry Kasparov, marking the first time a computer has defeated a reigning world chess champion in standard time control.

=== Super-human chess ===
In 2016, [[NPR]] asked experts to characterize the playing style of computer chess engines. [[Murray Campbell]] of IBM stated that "Computers don't have any sense of aesthetics... They play what they think is the objectively best move in any position, even if it looks absurd, and they can play any move no matter how ugly it is." Grandmasters Andrew Soltis and [[Susan Polgar]] stated that computers are more likely to retreat than humans are.<ref name="npr 20 years"/>

=== Neural network revolution ===
While [[Artificial neural network|neural networks]] have been used in the [[evaluation function]]s of chess engines since the late 1980s, with programs such as NeuroChess, Morph, Blondie25, Giraffe, [[AlphaZero]], and [[MuZero]],<ref>{{citation|title=Learning to Play the Game of Chess|last=Thurn|first=Sebastian|year=1995|publisher=MIT Press|url=https://proceedings.neurips.cc/paper/1994/file/d7322ed717dedf1eb4e6e52a37ea7bcd-Paper.pdf|access-date=12 December 2021}}</ref><ref>{{citation|title=A Self-Learning, Pattern-Oriented Chess Program|last=Levinson|first=Robert|year=1989|publisher=ICCA Journal|volume=12|issue=4}}</ref><ref name="Giraffe">{{citation|title=Giraffe: Using Deep Reinforcement Learning to Play Chess|last=Lai|first=Matthew|date=4 September 2015|arxiv=1509.01549v1}}</ref><ref>{{Cite arXiv|eprint = 1712.01815|last1 = Silver|first1 = David|last2 = Hubert|first2 = Thomas|last3 = Schrittwieser|first3 = Julian|last4 = Antonoglou|first4 = Ioannis|last5 = Lai|first5 = Matthew|last6 = Guez|first6 = Arthur|last7 = Lanctot|first7 = Marc|last8 = Sifre|first8 = Laurent|last9 = Kumaran|first9 = Dharshan|last10 = Graepel|first10 = Thore|last11 = Lillicrap|first11 = Timothy|last12 = Simonyan|first12 = Karen|last13 = Hassabis|first13 = Demis|title = Mastering Chess and Shogi by Self-Play with a General Reinforcement Learning Algorithm|year = 2017|class = cs.AI}}</ref><ref name="MuZero">{{cite journal|arxiv=1911.08265|first1=Julian|last1=Schrittwieser|first2=Ioannis|last2=Antonoglou|title=Mastering Atari, Go, chess and shogi by planning with a learned model|last3=Hubert|last9=Hassabis|first11=Timothy|last11=Lillicrap|first10=Thore|last10=Graepel|first9=Demis|first8=Edward|first3=Thomas|last8=Lockhart|last7=Guez|first6=Simon|last6=Schmitt|first5=Laurent|last5=Sifre|first4=Karen|last4=Simonyan|first7=Arthur|journal=Nature|year=2020|volume=588|issue=7839|pages=604–609|doi=10.1038/s41586-020-03051-4|pmid=33361790|bibcode=2020Natur.588..604S|s2cid=208158225}}</ref> neural networks did not become widely adopted by chess engines until the arrival of [[efficiently updatable neural network]]s in the summer of 2020. Efficiently updatable neural networks were originally developed in [[computer shogi]] in 2018 by Yu Nasu,<ref name="Nasu">{{cite web|title=Efficiently Updatable Neural-Network-based Evaluation Function for computer Shogi|author=Yu Nasu|url=https://www.apply.computer-shogi.org/wcsc28/appeal/the_end_of_genesis_T.N.K.evolution_turbo_type_D/nnue.pdf|date=April 28, 2018|language=Japanese}}</ref><ref name="Nasu2">{{cite web|title=Efficiently Updatable Neural-Network-based Evaluation Function for computer Shogi (Unofficial English Translation)|author=Yu Nasu|website=[[GitHub]]|url=https://github.com/asdfjkl/nnue/blob/main/nnue_en.pdf|date=April 28, 2018|language=English}}</ref> and had to be first ported to a derivative of Stockfish called Stockfish NNUE on 31 May 2020,<ref>{{cite web|url=https://github.com/nodchip/Stockfish/releases/tag/stockfish-nnue-2020-05-30|title=Release stockfish-nnue-2020-05-30|website=Github|last=Noda|first=Hisayori|date=30 May 2020|access-date=12 December 2021}}</ref> and integrated into the official Stockfish engine on 6 August 2020,<ref name="Introducing NNUE Evaluation">{{cite web|title=Introducing NNUE Evaluation|url=https://blog.stockfishchess.org/post/625828091343896577/introducing-nnue-evaluation|date=6 August 2020}}</ref><ref name="Joost VandeVondele">{{cite web|title= official-stockfish / Stockfish, NNUE merge|url=https://github.com/official-stockfish/Stockfish/issues/2823#issue-665540175|author=Joost VandeVondele|website=[[GitHub]]|date=July 25, 2020}}</ref> before other chess programmers began to adopt neural networks into their engines.

Some people, such as the [[Royal Society]]'s [[Venki Ramakrishnan]], believe that [[AlphaZero]] led to the widespread adoption of neural networks in chess engines.<ref>{{cite book |title=[[Possible Minds: Twenty-five Ways of Looking at AI]] |date=2019 |publisher=Penguin Press |isbn=978-0525557999 |edition=Kindle| page=174| chapter=[[Venki Ramakrishnan]]: Will Computers Become Our Overlords?}}</ref> However, AlphaZero influenced very few engines to begin using neural networks, and those tended to be new experimental engines such as [[Leela Chess Zero]], which began specifically to replicate the AlphaZero paper. The [[deep neural network]]s used in AlphaZero's evaluation function required expensive [[graphics processing units]], which were not compatible with existing chess engines. The vast majority of chess engines only use [[central processing units]], and computing and processing information on the GPUs require special [[Library (computing)|libraries]] in the backend such as [[Nvidia]]'s [[CUDA]], which none of the engines had access to. Thus the vast majority of chess engines such as [[Komodo (chess)|Komodo]] and [[Stockfish (chess)|Stockfish]] continued to use handcrafted evaluation functions until [[efficiently updatable neural network]]s were ported to computer chess from [[computer shogi]] in 2020, which did not require either the use of GPUs or libraries like CUDA at all. Even then, the neural networks used in computer chess are fairly shallow, and the [[deep reinforcement learning]] methods pioneered by AlphaZero are still extremely rare in computer chess.

=== Timeline ===
* 1769 – [[Wolfgang von Kempelen]] builds [[Mechanical Turk|the Turk]]. Presented as a chess-playing automaton, it is secretly operated by a human player hidden inside the machine.
* 1868 – Charles Hooper presents the [[Ajeeb]] automaton{{snd}} which also has a human chess player hidden inside.
* 1912 – [[Leonardo Torres y Quevedo]] builds [[El Ajedrecista]], a machine that could play [[wikibooks:Chess/The Endgame/King and Rook vs. King|King and Rook versus King endgames]].
* 1941 – Predating comparable work by at least a decade, [[Konrad Zuse]] develops computer chess algorithms in his [[Plankalkül]] programming formalism. Because of the circumstances of the Second World War, however, they were not published, and did not come to light, until the 1970s.
* 1948 – [[Norbert Wiener]]'s book ''Cybernetics'' describes how a chess program could be developed using a depth-limited minimax search with an [[evaluation function]].
* 1950 – [[Claude Shannon]] publishes "Programming a Computer for Playing Chess", one of the first papers on the algorithmic methods of computer chess.
* 1951 – [[Alan Turing]] is first to publish a program, developed on paper, that was capable of playing a full game of chess (dubbed [[Turochamp]]).<ref>Chess, a subsection of chapter 25, Digital Computers Applied to Games, of Faster than Thought, ed. B. V. Bowden, Pitman, London (1953). [https://web.archive.org/web/20031124134110/http://www.turingarchive.org/browse.php/B/7 Online].</ref><ref>[http://www.chessgames.com/perl/chessgame?gid=1356927 A game played by Turing's chess algorithm]</ref>
* 1952 – [[Dietrich Prinz]] develops a program that solves chess problems.
{{Chess diagram 6x6
| tright
|
|rd|nd|qd|kd|nd|rd
|pd|pd|pd|pd|pd|pd
|  |  |  |  |  |
|  |  |  |  |  |
|pl|pl|pl|pl|pl|pl
|rl|nl|ql|kl|nl|rl
| '''[[Los Alamos chess]]'''. This simplified version of chess was played in 1956 by the [[MANIAC I]] computer.
}}
* 1956 – [[Los Alamos chess]] is the first program to play a chess-like game, developed by Paul Stein and Mark Wells for the [[MANIAC I]] computer.
* 1956 – [[John McCarthy (computer scientist)|John McCarthy]] invents the [[alpha–beta pruning|alpha–beta]] search algorithm.
* 1957 – The first programs that can play a full game of chess are developed, one by Alex Bernstein<ref>{{cite web|url=http://www.chessville.com/BillWall/EarlyComputerChessPrograms.htm |title=Chessville – Early Computer Chess Programs – by Bill Wall – Bill Wall's Wonderful World of Chess |publisher=Archive.is |access-date=1 December 2014 |url-status=usurped |archive-url=https://archive.today/20120721202324/http://www.chessville.com/BillWall/EarlyComputerChessPrograms.htm |archive-date=21 July 2012}}</ref> and one by [[Russia]]n programmers using a [[BESM]].
* 1958 – NSS becomes the first chess program to use the alpha–beta search algorithm.
* 1962 – The first program to play credibly, [[Kotok-McCarthy]], is published at [[Massachusetts Institute of Technology|MIT]].
* 1963 – Grandmaster [[David Bronstein]] defeats an [[Minsk family of computers|M-20]] running an early chess program.<ref>[http://www.chessgames.com/perl/chessgame?gid=1238081 David Bronstein v M-20, replay at Chessgames.com]</ref>
* 1966–67 – The first chess match between computer programs is played. [[Moscow]] [[Institute for Theoretical and Experimental Physics]] (ITEP) defeats Kotok-McCarthy at [[Stanford University]] by telegraph over nine months.
* 1967 – [[MacHack (chess)|Mac Hack VI]], by [[Richard Greenblatt (programmer)|Richard Greenblatt]] et al. introduces [[transposition table]]s and employs dozens of carefully tuned move selection heuristics; it becomes the first program to defeat a person in tournament play.  Mac Hack VI played about C class level.
* 1968 – Scottish chess champion [[David Levy (chess player)|David Levy]] makes a 500 [[pound (monetary unit)|pound]] bet with AI pioneers [[John McCarthy (computer scientist)|John McCarthy]] and [[Donald Michie]] that no computer program would win a chess match against him within 10 years.
* 1970 – [[Monty Newborn]] and the [[Association for Computing Machinery]] organize the first [[North American Computer Chess Championship]]s in New York.
* 1971 – [[Ken Thompson]], an American Computer scientist at Bell Labs and creator of the Unix operating system, writes his first chess-playing program called "chess" for the earliest version of [[Unix]].<ref name="ritchie01">{{cite journal |journal=ICGA Journal |volume=24 |issue=2 |date=June 2001 |url=https://www.bell-labs.com/usr/dmr/www/ken-games.html|title=Ken, Unix and Games |author=[[Dennis Ritchie]]}}</ref>
* 1974 – [[David Levy (chess player)|David Levy]], Ben Mittman and [[Monty Newborn]] organize the first [[World Computer Chess Championship]] which is won by the Russian program [[Kaissa]].
* 1975 – After nearly a decade of only marginal progress since the high-water mark of Greenblatt's MacHack VI in 1967, Northwestern University Chess 4.5 is introduced featuring full-width search, and innovations of bitboards and iterative deepening. It also reinstated a transposition table as first seen in Greenblatt's program. It was thus the first program with an integrated modern structure and became the model for all future development. Chess 4.5 played strong B-class and won the 3rd World Computer Chess Championship the next year.<ref>{{cite web|url=https://link.springer.com/content/pdf/bbm%3A978-1-4612-5515-4%2F1.pdf|title=Appendix CHESS 4.5: Competition in 1976}}</ref> Northwestern University Chess and its descendants dominated computer chess until the era of hardware chess machines in the early 1980s.
* 1976 – In December, Canadian programmer [[Peter R. Jennings]] releases [[Microchess]], the first game for microcomputers to be sold.<ref>{{cite web|url=https://www.computerhistory.org/chess/orl-4334404555680/|title=Oral History of Peter Jennings &#124; Mastering the Game &#124; Computer History Museum}}</ref>
[[File:BorisChess.jpg|thumb|Released in 1977, Boris was one of the first chess computers to be widely marketed. It ran on a Fairchild F8 8-bit microprocessor with only 2.5 KiB ROM and 256 byte RAM.]]
* 1977 – In March, Fidelity Electronics releases [[Chess Challenger]], the first dedicated chess computer to be sold. The [[International Computer Chess Association]] is founded by chess programmers to organize computer chess championships and report on research and advancements on computer chess in their journal. Also that year, Applied Concepts released [[Boris (chess computer)|Boris]], a dedicated chess computer in a wooden box with plastic chess pieces and a folding board.
* 1978 – [[David Levy (chess player)|David Levy]] wins the bet made 10 years earlier, defeating [[Chess (Northwestern University)|Chess 4.7]] in a six-game match by a score of 4½–1½. The computer's victory in game four is the first defeat of a human master in a tournament.<ref name="douglas197812" />
* 1979 – [[Frederic Friedel]] organizes a match between IM [[David Levy (chess player)|David Levy]] and [[Chess (Northwestern University)|Chess 4.8]], which is broadcast on German television. Levy and Chess 4.8, running on a CDC Cyber 176, the most powerful computer in the world, fought a grueling 89 move draw.
* 1980 – Fidelity computers win the World Microcomputer Championships each year from 1980 through 1984. In Germany, Hegener & Glaser release their first [[Mephisto (chess computer)|Mephisto]] dedicated chess computer. The USCF prohibits computers from competing in human tournaments except when represented by the chess systems' creators.<ref name="byte198101">{{cite news |url=https://archive.org/stream/byte-magazine-1981-01/1981_01_BYTE_06-01_Hand-held_Computers#page/n293/mode/2up |title=New Restrictions |work=BYTE |date=January 1981 |access-date=18 October 2013 |page=292}}</ref> The Fredkin Prize, offering $100,000 to the creator of the first chess machine to defeat the world chess champion, is established.
* 1981 – [[Cray Blitz]] wins the Mississippi State Championship with a perfect 5–0 score and a performance rating of 2258. In round 4 it defeats Joe Sentef (2262) to become the first computer to beat a master in tournament play and the first computer to gain a master rating.
* 1984 –  The German Company Hegener & Glaser's ''[[Mephisto (chess computer)|Mephisto]]'' line of dedicated chess computers begins a long streak of victories (1984–1990) in the World Microcomputer Championship using dedicated computers running programs [[ChessGenius]] and [[REBEL (chess)|Rebel]].
* 1986 – Software Country (see [[Software Toolworks]]) released ''[[Chessmaster]] 2000'' based on an engine by David Kittinger, the first edition of what was to become the world's best selling line of chess programs.
* 1987 – [[Frederic Friedel]] and physicist Matthias Wüllenweber found [[Chessbase]], releasing the first chess database program.  Stuart Cracraft releases [[GNU Chess]], one of the first '[[chess engine]]s' to be bundled with a separate [[graphical user interface]] (GUI), {{proper name|chesstool}}.<ref>{{cite web|url=https://web.cecs.pdx.edu/~trent/gnu/bull/02/nb.html#SEC6|title = GNU's Bulletin, vol. 1 no. 2}}</ref>
* 1988 – [[HiTech]], developed by [[Hans Berliner]] and [[Carl Ebeling]], wins a match against grandmaster [[Arnold Denker]] 3½–½. [[Deep Thought (chess computer)|Deep Thought]] shares first place with [[Tony Miles]] in the Software Toolworks Championship, ahead of former world champion [[Mikhail Tal]] and several grandmasters including [[Samuel Reshevsky]], [[Walter Browne]] and [[Mikhail Gurevich (chess player)|Mikhail Gurevich]]. It also defeats grandmaster [[Bent Larsen]], making it the first computer to beat a GM in a tournament. Its [[Elo rating system|rating]] for performance in this tournament of 2745 (USCF scale) was the highest obtained by a computer player.<ref>Hsu (2002) p. 292</ref><ref>Newborn (1997) p. 159</ref>
* 1989 – Deep Thought demolishes David Levy in a 4-game match 0–4, bringing to an end his famous series of wagers starting in 1968.
* 1990 – On April 25, former world champion [[Anatoly Karpov]] lost in a simul to Hegener & Glaser's Mephisto Portorose M68030 chess computer.<ref>Selective Search. June 1990</ref>
* 1991 – The [[ChessMachine]] based on Ed Schröder's [[REBEL (chess)|Rebel]] wins the World Microcomputer Chess Championship
* 1992 – [[ChessMachine]] wins the 7th [[World Computer Chess Championship]], the first time a microcomputer beat [[mainframe computer|mainframes]]. GM [[John Nunn]] releases ''Secrets of Rook Endings'', the first book based on endgame tablebases developed by [[Ken Thompson]].
* 1993 – Deep Thought-2 loses a four-game match against [[Bent Larsen]]. Chess programs running on personal computers surpass Mephisto's dedicated chess computers to win the Microcomputer Championship, marking a shift from dedicated chess hardware to software on multipurpose personal computers.
* 1995 – [[Fritz (chess)|Fritz 3]], running on a 90&nbsp;Mhz Pentium PC, beats Deep Thought-2 dedicated chess machine, and programs running on several super-computers, to win the 8th [[World Computer Chess Championship]]s in Hong Kong. This marks the first time a chess program running on commodity hardware defeats specialized chess machines and massive super-computers, indicating a shift in emphasis from brute computational power to algorithmic improvements in the evolution of chess engines.
* 1996 – IBM's [[Deep Blue (chess computer)|Deep Blue]] loses a six-game match against [[Garry Kasparov]], 2–4.
* 1997 – [[Deep Blue (chess computer)|Deep(er) Blue]], a highly modified version of the original, wins a six-game match against [[Garry Kasparov]], 3.5–2.5.
* 2000 – [[Stefan Meyer-Kahlen]] and Rudolf Huber draft the [[Universal Chess Interface]], a protocol for GUIs to talk to engines that would gradually become the main form new engines would take.
* 2002 – [[Vladimir Kramnik]] ties an eight-game match against [[Deep Fritz]].
* 2003 – Kasparov draws a six-game match against [[Junior (chess program)|Deep Junior]] and draws a four-game match against [[X3D Fritz]].
* 2004 – a team of computers ([[Hydra (chess)|Hydra]], [[Junior (chess program)|Deep Junior]] and [[Fritz (chess)|Fritz]]) wins 8½–3½ against a strong human team formed by [[Veselin Topalov]], [[Ruslan Ponomariov]] and [[Sergey Karjakin]], who had an average [[Elo rating system|Elo]] rating of 2681. Fabien Letouzey releases the source code for Fruit 2.1, an engine quite competitive with the top closed-source engines of the time.  This leads many authors to revise their code, incorporating the new ideas.
* 2005 – [[Rybka]] wins the [[International Paderborn Computer Chess Championship|IPCCC]] tournament and very quickly afterwards becomes the strongest engine.<ref>[http://www.rybkachess.com/docs/PADERBORNCOMPUTER.htm International Paderborn Computer Chess Championship 2005]</ref>
* 2006 – The world champion, [[Vladimir Kramnik]], is defeated 4–2 by [[Deep Fritz]].
* 2009 – [[Pocket Fritz]]. 4 running on a smartphone, wins Copa Mercosur, an International Master level tournament, scoring 9½/10 and earning a performance rating of 2900.<ref name=PF4GM /> A group of pseudonymous Russian programmers release the source code of Ippolit, an engine seemingly stronger than [[Rybka]]. This becomes the basis for the engines Robbolito and Ivanhoe, and many engine authors adopt ideas from it.
* 2010 – Before the [[World Chess Championship 2010]], Topalov prepares by sparring against the supercomputer Blue Gene with 8,192 processors capable of 500&nbsp;trillion (5 × 10<sup>14</sup>) floating-point operations per second.<ref>{{cite web|url=http://www.chessbase.com/newsdetail.asp?newsid=6361 |title=Challenger uses supercomputer at the world chess championship|date=25 May 2010|publisher=Chessbase}}</ref> Rybka developer, [[Vasik Rajlich]], accuses Ippolit of being a clone of Rybka.
* 2011 – The ICGA strips Rybka of its WCCC titles.<ref>{{cite web |url=http://www.chessvibes.com/reports/rybka-disqualified-and-banned-from-world-computer-chess-championships/ |title= Rybka disqualified and banned from World Computer Chess Championships &#124; ChessVibes|website=www.chessvibes.com |archive-url=https://web.archive.org/web/20140330145657/http://www.chessvibes.com/reports/rybka-disqualified-and-banned-from-world-computer-chess-championships/ |archive-date=30 March 2014}}</ref><ref name=AGMoJiCCpo>{{cite news|last=Riis|first=Dr. Søren|title=A Gross Miscarriage of Justice in Computer Chess (part one)|url=http://www.chessbase.com/newsdetail.asp?newsid=7791|access-date=19 February 2012|newspaper=Chessbase News|date=2 January 2012}}</ref>
* 2017 – [[AlphaZero]], a neural net-based digital automaton, beats [[Stockfish (chess)|Stockfish]] 28–0, with 72 draws, in a 100-game match.
* 2018 – [[Efficiently updatable neural network]] (NNUE) evaluation is invented for [[computer shogi]].<ref>[[Yu Nasu]] (2018). ''ƎUИИ Efficiently Updatable Neural-Network based Evaluation Functions for Computer Shogi''. Ziosoft Computer Shogi Club, [https://github.com/ynasu87/nnue/blob/master/docs/nnue.pdf pdf] (Japanese with English abstract)</ref>
* 2019 – [[Leela Chess Zero]] (LCZero v0.21.1-nT40.T8.610), a chess engine based on AlphaZero, defeats [[Stockfish (chess)|Stockfish]] 19050918 in a 100-game match with the final score 53.5 to 46.5 to win [[Top Chess Engine Championship|TCEC]] season 15.<ref>https://cd.tcecbeta.club/archive.html?season=15&div=sf&game=1 TCEC season 15</ref>
* 2020 – NNUE is added to [[Stockfish (chess)|Stockfish]] evaluation, noticeably increasing its strength.<ref name="Introducing NNUE Evaluation" /><ref name="Joost VandeVondele" />