Rybka

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Rybka
Basic data

developer Vasik Rajlich et al. a.
Current  version 4.1
(March 8, 2011)
operating system Microsoft Windows
category Computer chess
License commercially
www.rybkachess.com
Vasik Rajlich, programmer at Rybka

Rybka ( Czech : little fish) has long been considered the strongest chess program in the world. The chief developer of the Rybka chess engine, which is available in a 32-bit and a 64-bit version, is the international master Vasik Rajlich . The team also included or belonged to Rajlich's wife Iweta , née Radziewicz, who bears the title of women's grandmaster , the grandmaster Larry Kaufman , who worked on the evaluation functions of the program, and Jeroen Noomen , who designed an opening book specially tailored to Rybka's playing style .

From 2007 to 2010 Rybka won the computer chess world championship four times , but was subsequently disqualified in June 2011 due to plagiarism allegations .

history

A beta version of Rybka 1.0 caused a sensation in December 2005 with excellent test results. It played better than any commercial engine back then . In March 2006 the commercial version 1.2 was published, for which there were several updates up to version 1.2f from May 2006. Since version 2.0 (June 2006) multiple processors are supported. Version 2.3.2a mp (supports multi-core processors) is now available free of charge. Under the name Rybka Winfinder there was a modified version, which is tactically stronger than the standard version of Rybka, especially with the motif "King's attack", but plays weaker overall in direct comparison, as well as a version Rybka 2.3 LK , which is based on suggestions in terms of figure evaluation Larry Kaufmans was modified.

Version 3 was released on August 6, 2008. Along with the standard engine, additional versions Rybka Dynamic and Rybka Human , each with a different playing style, and a version for Chess960 were delivered. The "Dynamic" version rates material lower and weights positional factors higher, the "Human" version contains algorithms developed by Larry Kaufman, which had a slightly negative effect on the skill level and were therefore not included in the standard version, but correspond to human experience .

Up to version 2, Rybka did not have its own user interface, but was integrated as a UCI engine in common chess front ends such as Arena , Chess Assistant , ChessBase or Shredder Classic . The program is distributed by the Russian company Convekta by download and since July 2006 also on DVD . Convekta developed its own user interface for Rybka ( aquarium ) for version 3. Rybka 3 is also marketed by ChessBase with an adapted Fritz user interface. The official opening books for Rybka 3 are written by Jeroen Noomen and distributed separately from Rybka by Chessbase and ChessOK. The opening book for Rybka 4 was written by Jiri Dufek.

Rybka 4 was released on May 26, 2010. Since February 1, 2011, Rybka has also been offered as a rental version that runs on a dedicated computer cluster .

Rybka was long considered the most powerful engine in the world and led the most important rankings worldwide (CCRL, CEGT and SSDF ), but was then ousted from this place by Houdini . By July 2014, the commercial program Komodo , the freeware program Critter and the open source programs Stockfish and Gull had surpassed the current version, Deep Rybka 4.1, in terms of short and long reflection periods.

Tournament results

Computer chess tournaments

Rybka was able to win several computer chess tournaments from 2005: the 15th IPCCC tournament in Paderborn, the CCT8 and the ICT6 in Leiden.

5th Livingston Chess960 Computer World Championship 2009 in Mainz. The 4 programs Deep Sjeng, Shredder, Rybka and Ikarus as well as their programming.
Lewon Aronjan kiebitzt during a game of Rybka - Shredder , Chess Classic 2009 in Mainz

At the 14th Computer World Championship in Turin in 2006, a test version of Rybka 2 under the name Rajlich took third place behind a test version by Junior and tied with a test version by Shredder (but with a poorer rating and defeat in direct comparison). In July 2006, the Rybka team, supported by Grandmaster Michał Krasenkow , won the 3rd PAL / CSS freestyle tournament. In November Rybka 2.2 won the 26th Open Computer Chess Championship of the Netherlands in Leiden with 9/9, in December the 16th IPCCC with 6.5 points from 7 games.

In May 2007 he won the ICT7 in Leiden, in June with version 2.3.2 he won the 15th World Computer Chess Championship in Amsterdam (10 points from 11 games, no defeat). In June the Rybka team (IM Iweta Rajlich, IM Vasik Rajlich and Rybka) won the 6th PAL / CSS freestyle tournament. In August Rybka won the computer world championship in Chess960 in Mainz . In October Rybka won the 27th Dutch Open Computer Chess Championship in Leiden and the 2nd Americas Computer Chess Championship. At the IPCCC 2007 Rybka had to admit defeat by HIARCS because of the poorer ranking (both scored 5.5 / 7 points).

In 2008 Rybka won the CCT10 together with Naum, and again the computer world championship in Chess960. In addition, Rybka defended her world title at the 16th computer chess world championship in Beijing with 8 points from 9 games, while the program was running on a computer cluster with 40 processors. With this hardware Rybka also won the 28th Dutch Open Computer Chess Championship in Leiden in November with 9 points from 9 games.

The year 2009 started with a victory at CCT 11 (both blitz and rapid chess) in March. A cluster with 52 cores was used and a book by Jeroen Noomen was used for the first time at the CCT. In May 2009 Rybka won the 17th World Computer Chess Championship in Pamplona with 8 points from 9 games . At this tournament the hardware was limited to a maximum of 8 cores, Rybka ran on an Intel Xeon W5580 with 3.2 GHz. The Blitz Championship was also won by Rybka on the same hardware. In addition to the world championship, the Olympics in Pamplona were also played, with no hardware restrictions. Rybka ran on a cluster with 9 computers and won with 5 points from 5 games. In August Rybka won the computer world championship in Chess 960 in Mainz with 14.5 points from 16 games, in October the 29th Dutch Open Computer Chess Championship in Leiden with 7.5 points from 8 games.

In September 2010 Rybka won the computer chess world championship in Kanazawa for the fourth time in a row with 8 points from 9 games. Hardware: 200 Nehalem EP Westmere, 2.93-3.6 GHz. In November 2010 Rybka won the 30th Open Dutch Computer Chess Championship in Leiden with 8.5 points from 9 games.

Results against human players

In January 2006 Rybka won a competition against the Chilean grandmaster Iván Morovic ( Elo 2551) with 1.5: 0.5. In March Rybka took part in a category IX tournament (Elo average 2460) in Santiago de Chile and won with 9 points from 10 games (8 wins, 2 draws). In October and December Rybka won two rapid chess games played on chess servers against Grandmaster Larry Christiansen .

In March 2007 Rybka won a handicap match against Jaan Ehlvest with 5.5-2.5, with the program playing with white in each of the 8 games, each with a pawn. In July Ehlvest faced Rybka again, this time he had white in every game and the program's opening book was limited to three moves. He also had twice the time to think about it. The match ended 4.5-1.5 in favor of Rybka. In August Rybka won a match with a pawn handicap against Joel Benjamin with 4.5-3.5. In contrast to the first match against Ehlvest, the program played alternately with white and black, with the pawns d2, c7, b2, a7, e2, f7, g2 and h7 being given. In September Rybka defeated Grandmaster Robert Fontaine , who had white in every game in Mexico , 2-0 in rapid chess.

In January 2008 Rybka played another match against Joel Benjamin, who had white in all eight games and a draw counted as a win. The result was 6-2 in favor of Rybka. In March 2008 an eight game match against grandmaster Roman Dzindzichashvili , in which Rybka pretended a pawn and always had black, ended with 4-4. In July there was another match against Dzindzichashvili, in which the computer gave the pawn f7 in four games with Black. The time limit was 30 minutes per game plus 20 seconds per move. Rybka won the competition 2.5-1.5 (one win, three draws). In September Rybka lost a match in eight games against Vadim Milov , who at the time had an Elo rating of 2705, with 3.5: 4.5. Two normal games were played in which Milov had white, two games with the specification of pawn f7 and move, and four games with specification of quality (rook a1 against knight b8). The thinking time was 90 minutes per game plus 30 seconds per move. Rybka won a game with Black, Milov one each with pawn and quality specifications, five games ended in a draw.

Play style and special features

As with many chess programs, Rybka's style of play has changed over the course of its development. While versions 1.0 up to and including 2.3.2a were considered to be positionally very mature, but with minor tactical weaknesses, this no longer applies since version 3 was released. Rybka 3 is tactically and especially in attacking the king very strong and has been significantly improved compared to the previous versions.

Rybka's evaluation function is very extensive and balanced, which tends to lead to objective and reliable position evaluations.

For programming reasons, some evaluation functions for the simplest endgames with 6 or fewer pieces have been removed since Rybka 2.3, which means that the use of Nalimov endgame databases can be useful for analysis. The real increase in skill level through the use of endgame databases is, according to the author, in the low double-digit Elo range.

Software plagiarism controversy

There are allegations that the first version of Rybka is based on the programming code from Fruit . Fruit 2.1 was released under the GNU General Public License in June 2005 , and six months later Rajlich released the beta version of Rybka. The evaluation functions of the two programs have a lot in common. Rajlich explained that although he took ideas from Fruit, he wrote his program code himself. In June 2011 Rybka was excluded from future tournaments of the International Computer Games Association , all world championship titles were revoked, whereas in 2012 a complaint was made to the ethics committee of the world chess federation FIDE .

For his part, Rajlich accused several programmers of having based their programs on decompiled versions of Rybka 3.

Web links

Individual evidence

  1. Demo download . (Retrieved April 2, 2011)
  2. Rybka Cluster , accessed February 20, 2011
  3. ^ Rybka Open Nederlands Kampioen 2008
  4. tournament page
  5. Tournament page of the Olympics
  6. tournament page
  7. David Levy : Attack of the clones , Chessvibes.com, February 19, 2011
  8. ^ David Levy: Rybka Disqualified and Banned from World Computer Chess Championships. In: International Computer Games Association . June 28, 2011, archived from the original on June 6, 2014 ; accessed on August 12, 2016 .
  9. ^ Roberto Rivello: Decisions of the FIDE Ethics Commission. (PDF (65 kB)) In: FIDE . July 1, 2012, accessed June 5, 2014 .
  10. ^ Arne Moll: Chess engine controversy , Chessvibes.com, March 29, 2010