In
computer chess
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 analysi ...
, a chess engine is a
computer program
A computer program is a sequence or set of instructions in a programming language for a computer to Execution (computing), execute. It is one component of software, which also includes software documentation, documentation and other intangibl ...
that analyzes
chess
Chess is a board game for two players. It is an abstract strategy game that involves Perfect information, no hidden information and no elements of game of chance, chance. It is played on a square chessboard, board consisting of 64 squares arran ...
or
chess variant
A chess variant is a game related to, derived from, or inspired by chess. Such variants can differ from chess in many different ways.
"International" or "Western" chess itself is one of a family of games which have related origins and could be co ...
positions, and generates a move or list of moves that it regards as strongest.
A chess
engine
An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy.
Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...
is usually a
back end with a
command-line interface
A command-line interface (CLI) is a means of interacting with software via command (computing), commands each formatted as a line of text. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user ...
with no graphics or
windowing. Engines are usually used with a front end, a windowed
graphical user interface
A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such ...
such as
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
or
WinBoard
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
that the user can interact with via a keyboard, mouse or touchscreen. This allows the user to play against multiple engines without learning a new user interface for each, and allows different engines to play against each other.
Many chess engines are now available for mobile phones and tablets, making them even more accessible.
History
The meaning of the term "chess engine" has evolved over time. In 1986, Linda and Tony Scherzer entered their program Bebe into the 4th
World Computer Chess Championship
World Computer Chess Championship (WCCC) was an event held periodically from 1974 to 2024 where computer chess engines compete against each other. The event is organized by the ''International Computer Games Association'' (ICGA, until 2002 ICCA). I ...
, running it on "Chess Engine," their brand name for the chess computer hardware made, and marketed by their company Sys-10, Inc. By 1990 the developers of
Deep Blue,
Feng-hsiung Hsu and
Murray Campbell
Murray Campbell is a Canadian computer scientist known for being part of the team that created Deep Blue; the first computer to defeat a world chess champion.
Career Chess computing
Around 1986, he and other students at Carnegie Mellon bega ...
, were writing of giving their program a 'searching engine,' apparently referring to the software rather than the hardware. In December 1991, ''Computer-schach & Spiele'' referred to
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
's recently released
Fritz
Fritz is a common German language, German male name. The name originated as a German diminutive of Friedrich (given name), Friedrich or Frederick (given name), Frederick (''Der Alte Fritz'', and ''Stary Fryc'' were common nicknames for King Fred ...
as a 'Schach-motor,' the German translation for 'chess engine.' By early 1993, Marty Hirsch was drawing a distinction between commercial chess programs such as ''
Chessmaster
''Chessmaster'' (originally ''The Chessmaster'') is a chess video game series, currently owned and developed by Ubisoft. It is the best-selling chess video game series, with more than five million units sold . The same cover art image featuring ...
3000'' or ''
Battle Chess'' on the one hand, and 'chess engines' such as ''
ChessGenius'' or his own ''
MChess Pro'' on the other. In his characterization, commercial chess programs were low in price, had fancy graphics, but did not place high on the SSDF (
Swedish Chess Computer Association
The Swedish Chess Computer Association (, SSDF) is an organization that tests computer chess software by playing chess programs against one another and producing a rating list. On September 26, 2008, the list was released with Deep Rybka 3 leading ...
) rating lists while engines were more expensive, and did have high ratings.
In 1994, Shay Bushinsky was working on an early version of his ''
Junior'' program. He wanted to focus on the chess playing part rather than the graphics, and so asked Tim Mann how he could get ''Junior'' to communicate with ''
Winboard
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
.'' Tim's answer formed the basis for what became known as the Chess Engine Communication Protocol or Winboard engines, originally a subset of the
GNU Chess
GNU Chess is a free software chess engine and command-line interface chessboard. The goal of GNU Chess is to serve as a basis for research, and as such it has been used in numerous contexts.
GNU Chess is free software, licensed under the terms ...
command line interface.
Also in 1994, Stephen J. Edwards released the
Portable Game Notation
Portable Game Notation (PGN) is a standard plain text format for recording chess games (both the moves and related data), which can be read by humans and is also supported by most chess software.
History
PGN was devised around 1993, by Steven J ...
(PGN) specification. It mentions PGN reading programs not needing to have a "full chess engine." It also mentions three "graphical user interfaces" (GUI):
XBoard
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
, pgnRead and Slappy the database.
By the mid-2000s, engines had become so strong that they were able to beat even the best human players. Except for entertainment purposes, especially using engines with limited strength, matches between humans and engines are now rare; engines are increasingly regarded as tools for analysis rather than as opponents.
Interface protocol
Common Winboard engines would include ''
Crafty
Crafty is a chess program written by UAB professor Robert Hyatt, with development and assistance from Michael Byrne, Tracy Riegle, and Peter Skinner. It is derived from Cray Blitz, winner of the 1983 and 1986 World Computer Chess Championshi ...
,'' ''ProDeo'' (based on ''
Rebel''), ''Chenard,'' ''
Zarkov
Dr. Hans Zarkov is a fictional character appearing in the ''Flash Gordon'' comic strip and the following serials, films, television shows and comic books. Zarkov is a brilliant scientist who creates a rocket and forces Flash and Dale Arden to c ...
'' and ''Phalanx.''
In 1995,
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
released a version of their database program including
Fritz
Fritz is a common German language, German male name. The name originated as a German diminutive of Friedrich (given name), Friedrich or Frederick (given name), Frederick (''Der Alte Fritz'', and ''Stary Fryc'' were common nicknames for King Fred ...
4 as a separate engine. This was the first appearance of the Chessbase protocol. Soon after, they added the engines
Junior and
Shredder to their product line up, including engines in CB protocol as separate programs which could be installed in the
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
program or one of the other Fritz style GUI's. Fritz 1-14 were only issued as Chessbase engines, while ''
Hiarcs,'' ''Nimzo,'' ''
Chess Tiger'' and ''
Crafty
Crafty is a chess program written by UAB professor Robert Hyatt, with development and assistance from Michael Byrne, Tracy Riegle, and Peter Skinner. It is derived from Cray Blitz, winner of the 1983 and 1986 World Computer Chess Championshi ...
'' have been ported to Chessbase format even though they were UCI or Winboard engines. Recently, Chessbase has begun to include
Universal Chess Interface
The Universal Chess Interface (UCI) is an open communication protocol that enables chess engines to communicate with user interfaces.
History
In November 2000, the UCI protocol was released. Designed by Rudolf Huber and Stefan Meyer-Kahlen, the ...
(UCI) engines in their playing programs such as ''
Komodo,'' ''
Houdini
Erik Weisz (March 24, 1874 – October 31, 1926), known professionally as Harry Houdini ( ), was a Hungarian-American escapologist, illusionist, and stunt performer noted for his escape acts.
Houdini first attracted notice in vaudeville in ...
,'' ''
Fritz
Fritz is a common German language, German male name. The name originated as a German diminutive of Friedrich (given name), Friedrich or Frederick (given name), Frederick (''Der Alte Fritz'', and ''Stary Fryc'' were common nicknames for King Fred ...
15–16'' and ''
Rybka
Rybka is a computer chess engine designed by International Master Vasik Rajlich. Around 2011, Rybka was one of the top-rated engines on chess engine rating lists and won many computer chess tournaments.
After Rybka won four consecutive Wor ...
'' rather than convert them to Chessbase engines.
In 2000,
Stefan Meyer-Kahlen and Franz Huber released the
Universal Chess Interface
The Universal Chess Interface (UCI) is an open communication protocol that enables chess engines to communicate with user interfaces.
History
In November 2000, the UCI protocol was released. Designed by Rudolf Huber and Stefan Meyer-Kahlen, the ...
, a more detailed protocol that introduced a wider set of features.
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
soon after dropped support for Winboard engines, and added support for UCI to their engine GUI's and
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
programs. Most of the top engines are UCI these days: ''
Stockfish
Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks (which are called "hjell" in Norway) on the foreshore. The drying of food is the world's oldest known preservation method, and dried fish has a storage li ...
,'' ''
Komodo,'' ''
Leela Chess Zero,'' ''
Houdini
Erik Weisz (March 24, 1874 – October 31, 1926), known professionally as Harry Houdini ( ), was a Hungarian-American escapologist, illusionist, and stunt performer noted for his escape acts.
Houdini first attracted notice in vaudeville in ...
,'' ''
Fritz
Fritz is a common German language, German male name. The name originated as a German diminutive of Friedrich (given name), Friedrich or Frederick (given name), Frederick (''Der Alte Fritz'', and ''Stary Fryc'' were common nicknames for King Fred ...
15-16,'' ''
Rybka
Rybka is a computer chess engine designed by International Master Vasik Rajlich. Around 2011, Rybka was one of the top-rated engines on chess engine rating lists and won many computer chess tournaments.
After Rybka won four consecutive Wor ...
,'' ''
Shredder,'' ''
Fruit
In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering.
Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...
,'' ''
Critter,'' ''
Ivanhoe
''Ivanhoe: A Romance'' ( ) by Walter Scott is a historical novel published in three volumes, in December 1819, as one of the Waverley novels. It marked a shift away from Scott's prior practice of setting stories in Scotland and in the more ...
'' and ''Ruffian.''
From 1998, the German company Millenium 2000 briefly moved from dedicated chess computers into the software market, developing the Millennium Chess System (MCS) protocol for a series of CD's containing ''
ChessGenius'' or ''
Shredder,'' but after 2001 ceased releasing new software. A more longstanding engine protocol has been used by the Dutch company, Lokasoft, which eventually took over the marketing of Ed Schröder's ''
Rebel.''
Increasing strength
Chess engines increase in playing strength continually. This is partly due to the increase in processing power that enables calculations to be made to ever greater depths in a given time. In addition, programming techniques have improved, enabling the engines to be more selective in the lines that they analyze and to acquire a better positional understanding. A chess engine often uses a vast previously-computed opening "book" to increase its playing strength for the first several moves, up to possibly 20 moves or more in deeply analyzed lines.

Some chess engines maintain a database of chess positions, along with previously-computed evaluations and best moves—in effect, a kind of "dictionary" of recurring chess positions. Since these positions are pre-computed, the engine merely plays one of the indicated moves in the database, thereby saving computing time, resulting in stronger, faster play.
Some chess engines use
endgame tablebase
In chess, the endgame tablebase, or simply the tablebase, is a computerised database containing precalculated evaluations of chess endgame, endgame positions. Tablebases are used to analyse finished games, as well as by chess engines to evaluate ...
s to increase their playing strength during the
endgame. An endgame tablebase includes all possible endgame positions with a small amount of material. Each position is conclusively determined as a win, loss, or draw for the player whose turn it is to move, and the number of moves to the end with best play by both sides. The tablebase identifies for every position the move which will win the fastest against an optimal defense, or the move that will lose the slowest against an optimal offense. Such tablebases are available for all chess endgames with seven pieces or fewer (trivial endgame positions are excluded, such as six white pieces versus a lone black
king
King is a royal title given to a male monarch. A king is an Absolute monarchy, absolute monarch if he holds unrestricted Government, governmental power or exercises full sovereignty over a nation. Conversely, he is a Constitutional monarchy, ...
).
When the maneuvering in an ending to achieve an irreversible improvement takes more moves than the horizon of calculation of a chess engine, an engine is not guaranteed to find the best move without the use of an endgame tablebase, and in many cases can fall foul of the
fifty-move rule as a result. Many engines use
permanent brain (continuing to calculate during the opponent's turn) as a method to increase their strength.
Distributed computing
Distributed computing is a field of computer science that studies distributed systems, defined as computer systems whose inter-communicating components are located on different networked computers.
The components of a distributed system commu ...
is also used to improve the software code of chess engines. In 2013, the developers of the
Stockfish
Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks (which are called "hjell" in Norway) on the foreshore. The drying of food is the world's oldest known preservation method, and dried fish has a storage li ...
chess playing program started using distributed computing to make improvements in the software code. , a total of more than 745 years of CPU time has been used to play more than 485 million chess games, with the results being used to make small and incremental improvements to the chess-playing software. In 2019, Ethereal author Andrew Grant started the distributed computing testing framework OpenBench, based upon Stockfish's testing framework, and it is now the most widely-used testing framework for chess engines.
Limiting an engine's strength
By the late 1990s, the top engines had become so strong that few players stood a chance of winning a game against them. To give players more of a chance, engines began to include settings to adjust or limit their strength. In 2000, when
Stefan Meyer-Kahlen and Franz Huber released the
Universal Chess Interface
The Universal Chess Interface (UCI) is an open communication protocol that enables chess engines to communicate with user interfaces.
History
In November 2000, the UCI protocol was released. Designed by Rudolf Huber and Stefan Meyer-Kahlen, the ...
protocol they included the parameters uci_limitstrength and uci_elo allowing engine authors to offer a variety of levels rated in accordance with
Elo rating
The Elo rating system is a method for calculating the relative skill levels of players in zero-sum games such as chess or esports. It is named after its creator Arpad Elo, a Hungarian-American chess master and physics professor.
The Elo system wa ...
, as calibrated by one of the rating lists. Most GUIs for UCI engines allow users to set this Elo rating within the menus. Even engines that have not adopted this parameter will sometimes have an adjustable strength parameter (e.g. Stockfish 11). Engines which have a uci_elo parameter include
Houdini
Erik Weisz (March 24, 1874 – October 31, 1926), known professionally as Harry Houdini ( ), was a Hungarian-American escapologist, illusionist, and stunt performer noted for his escape acts.
Houdini first attracted notice in vaudeville in ...
,
Fritz
Fritz is a common German language, German male name. The name originated as a German diminutive of Friedrich (given name), Friedrich or Frederick (given name), Frederick (''Der Alte Fritz'', and ''Stary Fryc'' were common nicknames for King Fred ...
15–16,
Rybka
Rybka is a computer chess engine designed by International Master Vasik Rajlich. Around 2011, Rybka was one of the top-rated engines on chess engine rating lists and won many computer chess tournaments.
After Rybka won four consecutive Wor ...
,
Shredder,
Hiarcs,
Junior,
Zappa, and
Sjeng. GUIs such as
Shredder,
Chess Assistant, Convekta Aquarium,
Hiarcs Chess Explorer, and Martin Blume's Arena
have dropdown menus for setting the engine's uci_elo parameter. The Fritz family GUIs,
Chess Assistant, and Aquarium also have independent means of limiting an engine's strength apparently based on an engine's ability to generate ranked lists of moves (called multipv for 'principle variation').
Comparisons
Tournaments
The results of computer tournaments give one view of the relative strengths of chess engines. However, tournaments do not play a statistically significant number of games for accurate strength determination. In fact, the number of games that need to be played between fairly evenly matched engines, in order to achieve significance, runs into the thousands and is, therefore, impractical within the framework of a tournament. Most tournaments also allow any types of hardware, so only engine/hardware combinations are being compared.
Historically, commercial programs have been the strongest engines. If an amateur engine wins a tournament or otherwise performs well (for example,
Zappa in 2005), then it is quickly commercialized. Titles gained in these tournaments garner much prestige for the winning programs, and are thus used for marketing purposes. However, after the rise of
volunteer distributed computing
Distributed computing is a field of computer science that studies distributed systems, defined as computer systems whose inter-communicating components are located on different networked computers.
The components of a distributed system commu ...
projects such as
Leela Chess Zero and
Stockfish
Stockfish is unsalted fish, especially cod, dried by cold air and wind on wooden racks (which are called "hjell" in Norway) on the foreshore. The drying of food is the world's oldest known preservation method, and dried fish has a storage li ...
and testing frameworks such as FishTest and OpenBench in the late 2010s,
free and open source
Free and open-source software (FOSS) is software available under a license that grants users the right to use, modify, and distribute the software modified or not to everyone free of charge. FOSS is an inclusive umbrella term encompassing free ...
programs have largely displaced commercial programs as the strongest engines in tournaments.
List of tournaments
Current tournaments include:
*
Top Chess Engine Championship (TCEC)
*
Chess.com Computer Chess Championship (CCC)
Historic tournaments include:
*
Dutch Open Computer Chess Championship
*
Internet Computer Chess Tournament (CCT)
*
International Paderborn Computer Chess Championship
*
North American Computer Chess Championship
The North American Computer Chess Championship was a computer chess championship held from 1970 to 1994. It was organised by the Association for Computing Machinery and by Monty Newborn, professor of computer science at McGill University. It was o ...
*
World Computer Chess Championship
World Computer Chess Championship (WCCC) was an event held periodically from 1974 to 2024 where computer chess engines compete against each other. The event is organized by the ''International Computer Games Association'' (ICGA, until 2002 ICCA). I ...
(WCCC and WCSC)
**
World Computer Speed Chess Championship
Ratings
Chess engine rating lists aim to provide statistically significant measures of relative engine strength. These lists play multiple games between engines. Some also standardize the opening books, the
time control
A time control is a mechanism in the tournament play of almost all two-player board games so that each round of the match can finish in a timely way and the tournament can proceed.
For turn-based games such as chess, shogi or go, time cont ...
s, and the
computer hardware
Computer hardware includes the physical parts of a computer, such as the central processing unit (CPU), random-access memory (RAM), motherboard, computer data storage, graphics card, sound card, and computer case. It includes external devices ...
the engines use, in an attempt to measure the strength differences of the engines only. These lists provide not only a ranking, but also margins of error on the given ratings.
The ratings on the rating lists, although calculated by using the
Elo system (or similar rating methods), have no direct relation to FIDE Elo ratings or to other chess federation ratings of human players. Except for some man versus machine games which the SSDF had organized many years ago (when engines were far from today's strength), there is ''no calibration'' between any of these rating lists and player pools. Hence, the results which matter are the ''ranks'' and the ''differences'' between the ratings, and not the absolute values.
Missing from many rating lists are
IPPOLIT and its derivatives. Although very strong and
open source
Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use and view the source code, design documents, or content of the product. The open source model is a decentrali ...
, there are allegations from commercial software interests that they were derived from a disassembled binary of
Rybka
Rybka is a computer chess engine designed by International Master Vasik Rajlich. Around 2011, Rybka was one of the top-rated engines on chess engine rating lists and won many computer chess tournaments.
After Rybka won four consecutive Wor ...
. Due to the
controversy
Controversy (, ) is a state of prolonged public dispute or debate, usually concerning a matter of conflicting opinion or point of view. The word was coined from the Latin '' controversia'', as a composite of ''controversus'' – "turned in an op ...
, all these engines have been blacklisted from many tournaments and rating lists. Rybka in turn was accused of being based on
Fruit
In botany, a fruit is the seed-bearing structure in flowering plants (angiosperms) that is formed from the ovary after flowering.
Fruits are the means by which angiosperms disseminate their seeds. Edible fruits in particular have long propaga ...
, and in June 2011, the ICGA formally claimed Rybka was derived from Fruit and Crafty and banned Rybka from the International Computer Games Association World Computer Chess Championship, and revoked its previous victories (2007, 2008, 2009, and 2010). The ICGA received some criticism for this decision.
Despite all this, Rybka is still included on many rating lists, such as CCRL and CEGT, in addition to
Houdini
Erik Weisz (March 24, 1874 – October 31, 1926), known professionally as Harry Houdini ( ), was a Hungarian-American escapologist, illusionist, and stunt performer noted for his escape acts.
Houdini first attracted notice in vaudeville in ...
, a derivative of the IPPOLIT derivative Robbolito,
and Fire, a derivative of Houdini. In addition,
Fat Fritz 2, a derivative of Stockfish, is also included on most of the rating lists.
Differences between rating lists
There are a number of factors that vary among the chess engine rating lists:
* Number of games.
More games when testing each engine result in higher
statistical significance
In statistical hypothesis testing, a result has statistical significance when a result at least as "extreme" would be very infrequent if the null hypothesis were true. More precisely, a study's defined significance level, denoted by \alpha, is the ...
.
* Formulae used to calculate the elo of each engine.
*
Time control
A time control is a mechanism in the tournament play of almost all two-player board games so that each round of the match can finish in a timely way and the tournament can proceed.
For turn-based games such as chess, shogi or go, time cont ...
:
** Longer time controls are better suited for determining tournament play strength, but also either make testing more time-consuming or the results less statistically significant.
** Increment time controls are better suited for determining tournament play strength since tournaments usually use increment time controls, but many rating lists use cyclic/repeating time controls instead.
** Consistent time controls throughout the rating list vs different time controls for each test. The latter results in a smaller
statistical significance
In statistical hypothesis testing, a result has statistical significance when a result at least as "extreme" would be very infrequent if the null hypothesis were true. More precisely, a study's defined significance level, denoted by \alpha, is the ...
than the former because different time controls is a potential
confounder. This is particularly problematic for CCRL because CCRL uses both cyclic/repeating time controls (40/15) and increment time controls (15"+10') in its CCRL 40/15 list yet maintains both time controls on the same list.
* Opponents used in testing engines.
** Some rating lists only test an engine against the most recent version of each opponent engine, while other rating lists test an engine against the version(s) of each opponent engine closest in elo to the engine being tested.
** Most rating lists do not test every engine on the rating list vs every other engine on the rating list in a
round-robin tournament
A round-robin tournament or all-play-all tournament is a competition format in which each contestant meets every other participant, usually in turn.''Webster's Third New International Dictionary of the English Language, Unabridged'' (1971, G. & ...
format. This causes distortions in the rating lists, especially for CCRL and CEGT.
* Hardware used:
** Faster hardware with more memory leads to stronger play.
** 64-bit (vs. 32-bit) hardware and operating systems favor
bitboard-based programs
** Hardware using modern instruction sets such as
AVX2
Advanced Vector Extensions (AVX, also known as Gesher New Instructions and then Sandy Bridge New Instructions) are SIMD extensions to the x86 instruction set architecture for microprocessors from Intel and Advanced Micro Devices (AMD). They w ...
or
AVX512
AVX-512 are 512-bit extensions to the 256-bit Advanced Vector Extensions SIMD instructions for x86 instruction set architecture (ISA) proposed by Intel in July 2013, and first implemented in the 2016 Intel Xeon Phi x200 (Knights Landing), and ...
favor engines using vectors and vector intrinsics in their code, common in
neural networks
A neural network is a group of interconnected units called neurons that send signals to one another. Neurons can be either Cell (biology), biological cells or signal pathways. While individual neurons are simple, many of them together in a netwo ...
.
**
Graphics processing units
A graphics processing unit (GPU) is a specialized electronic circuit designed for digital image processing and to accelerate computer graphics, being present either as a discrete video card or embedded on motherboards, mobile phones, personal co ...
favor programs with
deep neural networks
Deep learning is a subset of machine learning that focuses on utilizing multilayered neural networks to perform tasks such as classification, regression, and representation learning. The field takes inspiration from biological neuroscience a ...
.
** Multiprocessor vs. single processor hardware.
** Consistent hardware throughout the rating list vs different hardware for every test. The latter results in a smaller
statistical significance
In statistical hypothesis testing, a result has statistical significance when a result at least as "extreme" would be very infrequent if the null hypothesis were true. More precisely, a study's defined significance level, denoted by \alpha, is the ...
than the former because different hardware is a potential
confounder. This is particularly problematic for
CEGT because multiple testers each with their own unique hardware are involved in testing each engine in CEGT. The same issue arises in
CCRL.
* Ponder settings (speculative analysis while the opponent is thinking) aka Permanent Brain.
* Transposition table sizes.
* GUI settings.
* Opening book settings.
These differences affect the results, and make direct comparisons between rating lists difficult.
List of rating lists
Current rating lists and rating list organizations include:
Computer Chess Rating Lists(CCRL)
*
CCRL Blitz 2+1*
CCRL 40/15
*
CCRL FRC*
Chess Engines Grand Tournament (CEGT)
*
CEGT Blitz*
*
*
*
*
Stefan Pohl Computer Chess(SPCC)
Mac Chess Engine Rating List(MCERL)
Ipman Chess*
Ipman Chess AMD Ryzen 9 7945HX*
Ipman Chess Intel i9 7980XE*
Ipman Chess Intel i7 13700H
Historic rating lists and rating list organizations include:
Computer Chess Rating Lists(CCRL)
*
CCRL 40/2 ArchiveFastGM's Rating List(FGRL)
*
*
Ipman Chess*
Ipman Chess i7 970*
Ipman Chess Intel i7 11800H*
Ipman Chess i7 2670QM*
Ipman Chess List i3 M380*
Ipman Chess i7 5960x(GRL)
FastGM's Rating List(FGRL)
*
*
*
*
Anti Draw Rating List(ADRL)
*
ADRL Blitz*
ADRL 40/120
Test suites
Engines can be tested by measuring their performance on specific positions. Typical is the use of test suites where for each given position there is one best move to find. These positions can be geared towards positional, tactical or endgame play. The
Nolot test suite, for instance, focuses on deep sacrifices. The BT2450 and BT2630 test suites measure the tactical capability of a chess engine and have been used by
REBEL. There is also a general test suite called Brilliancy which was compiled mostly from ''How to Reassess Your Chess Workbook''. The Strategic Test Suite (STS) tests an engine's strategical strength. Another modern test suite is Nightmare II which contains 30 chess puzzles.
Kasparov versus the World (chess game played with computer assistance)
In 1999,
Garry Kasparov
Garry Kimovich Kasparov (born Garik Kimovich Weinstein on 13 April 1963) is a Russian Grandmaster (chess), chess grandmaster, former World Chess Champion (1985–2000), political activist and writer. His peak FIDE chess Elo rating system, ra ...
played a chess game called "Kasparov versus the World" over the
Internet
The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...
, hosted by the
MSN Gaming Zone. Both sides used computer (chess engine) assistance. The "World Team" included the participation of over 50,000 people from more than 75 countries, deciding their moves by
plurality vote
Plurality may refer to:
Law and politics
* Plurality decision, in a decision by a multi-member court, an opinion held by more judges than any other but not by an overall majority
* Plurality (voting), when a candidate or proposition polls more ...
. The game lasted four months, ending after Kasparov's 62nd move when he announced a forced
checkmate
Checkmate (often shortened to mate) is any game position in chess and other chess-like games in which a player's king is in check (threatened with ) and there is no possible escape. Checkmating the opponent wins the game.
In chess, the king is ...
in 28 moves found with the computer program
Deep Junior. The World Team voters resigned on October 22. After the game, Kasparov said: "It is the greatest game in the history of chess. The sheer number of ideas, the complexity, and the contribution it has made to chess make it the most important game ever played."
Engines for chess variants
Some chess engines have been developed to play
chess variants, adding the necessary code to simulate
non-standard chess pieces, or to analyze play on non-standard boards.
ChessV and
Fairy-Max
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
, for example, are both capable of playing variants on a chessboard up to 12×8 in size, such as
Capablanca Chess (10×8 board).
For larger boards, however, there are few chess engines that can play effectively, and indeed chess games played on an unbounded chessboard (
infinite chess) are virtually untouched by chess-playing software, although theoretically a program using a
MuZero-derived algorithm could handle an unbounded
state space
In computer science, a state space is a discrete space representing the set of all possible configurations of a system. It is a useful abstraction for reasoning about the behavior of a given system and is widely used in the fields of artificial ...
.
Graphical user interfaces
XBoard
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
/
Winboard
XBoard is a graphical user interface chessboard for chess engines under the X Window System. It is developed and maintained as free software by the GNU project. WinBoard is a port of XBoard to run natively on Microsoft Windows.
Overview
Original ...
was one of the earliest
graphical user interface
A graphical user interface, or GUI, is a form of user interface that allows user (computing), users to human–computer interaction, interact with electronic devices through Graphics, graphical icon (computing), icons and visual indicators such ...
s (GUI). Tim Mann created it to provide a GUI for the
GNU Chess
GNU Chess is a free software chess engine and command-line interface chessboard. The goal of GNU Chess is to serve as a basis for research, and as such it has been used in numerous contexts.
GNU Chess is free software, licensed under the terms ...
engine, but after that, other engines such as
Crafty
Crafty is a chess program written by UAB professor Robert Hyatt, with development and assistance from Michael Byrne, Tracy Riegle, and Peter Skinner. It is derived from Cray Blitz, winner of the 1983 and 1986 World Computer Chess Championshi ...
appeared which used the Winboard protocol. Eventually, the program
Chessmaster
''Chessmaster'' (originally ''The Chessmaster'') is a chess video game series, currently owned and developed by Ubisoft. It is the best-selling chess video game series, with more than five million units sold . The same cover art image featuring ...
included the option to import other Winboard engines in addition to the King engine which was included.
In 1995,
Chessbase
ChessBase is a German company that develops and sells chess software, maintains a chess news site, and operates an internet chess server for online chess. Founded in 1986, it maintains and sells large-scale databases containing the moves of recor ...
began offering the
Fritz
Fritz is a common German language, German male name. The name originated as a German diminutive of Friedrich (given name), Friedrich or Frederick (given name), Frederick (''Der Alte Fritz'', and ''Stary Fryc'' were common nicknames for King Fred ...
engine as a separate program within the Chessbase database program and within the Fritz GUI. Soon after, they added the
Junior and
Shredder engines to their product line up, packaging them within the same GUI as was used for Fritz. In the late 1990s, the Fritz GUI was able to run Winboard engines via an adapter, but after 2000, Chessbase simply added support for UCI engines, and no longer invested much effort in Winboard.
In 2000,
Stefan Meyer-Kahlen started selling Shredder in a separate
UCI GUI of his own design, allowing UCI or Winboard engines to be imported into it.
Convekta's
Chess Assistant and Lokasoft's ChessPartner also added the ability to import Winboard and UCI engines into their products. Shane Hudson developed
Shane's Chess Information Database, a free GUI for Linux, Mac and Windows. Martin Blume developed Arena,
[ another free GUI for Linux and Windows. Lucas Monge entered the field with the free Lucas Chess GUI. All three can handle both UCI and Winboard engines.
On Android, Aart Bik came out with Chess for Android, another free GUI, and Gerhard Kalab's Chess PGN Master and Peter Osterlund's Droidfish can also serve as GUIs for engines.
The Computer Chess Wiki lists many chess GUIs.]
See also
* Chess variants
* Computer chess
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 analysi ...
* Correspondence chess
Correspondence chess is chess played by various forms of long-distance correspondence, traditionally through the postal system. Today it is usually played through a correspondence chess server, a public internet chess forum, or email. Less commo ...
* Internet chess server
* List of chess software
Chess software comes in different forms. A chess playing program provides a graphical chessboard on which one can play a chess game against a computer. Such programs are available for personal computers, video game consoles, smartphones/tablet com ...
* Dietrich Prinz's Chess Program
Notes
References
External links
Chess Engine's Polyglot Opening Book for WinBoard GUI
- A general (learning) purpose Chess Engine's Polyglot Opening Book for WinBoard GUI.
Chess Programming Wiki
{{DEFAULTSORT:Chess Engine
Computer chess