Rybka and Rajlich

Rybka is a closed-source computer chess engine designed and programmed by International Master Vasik Rajlich. Rybka supports both single processor and symmetric multiprocessing (SMP) systems. Its website is rybkachess.com. Rybka is a UCI engine with 32 and 54-bit versions available. Rybka can be made the default engine in ChessBase 10.

Rybka means “little fish” in Czech and other Slavic languages.

Rybka’s search is considered its main advantage over other programs. Its efficient design as a bitboard engine gives it an extra 60% processing efficiency when run in 64-bit mode. The details of the evaluation function are unknown. Its opening book contains almost 4 million positions.

Vasik was born in Cleveland, Ohio in 1971 to Czech parents. He grew up in Prague, then returned to the United States as a student, graduated from MIT. Recently he has resided in Budapest and now lives in Warsaw, Poland. His father teaches computer science in Detroit. His mother is a mathematician. Two of his brothers are computer scientists and a third brother is a medical doctor.

Vaski is married to Polish born IM/WGM Iweta Radziewicz Rajlich She helped him with the development of Rybka.

The Rybka team includes Vasik Raijlich (Rybka developer), Iweta Rajlich (tester), Dr. Lukas Cimiotti (hardware expert), IM Jeroen Noomen (opening book author), Jiri Dufek (opening book author), Felix Kling (webmaster), Christoph Kling (website designer), GM Larry Kaufman (advisor and in charge of the evaluation function and positional algorithms), Hans van der Zijden (operator), and Nick Carlin (opening book author and operator).

In 2003, Vasik started working on his chess program.

In January 2004, Rybka participated in the 6^th Programmers Computer Chess Tournament (CCT6) and took 53^rd place out of 54 competitors. It won 1 game, lost 5, and drew 3.

In April 2004, Rybka participated in Chess War V, finishing 23^rd.

In April 2004, Rybka participated in the Swiss System 3 by Claude Dubois and took 71^st with 6 wins, 6 losses, and 6 draws.

On December 2, 2005, the first Rybka beta was released. In a December 5, 2008, interview, Rajlich said, “…the publication of Fruit 2.1 was huge….I went through the Fruit 2.1 source code forwards and backwards and took many things.”

In December 2005, Rybka participated in the 15^th International Paderborn Computer Championship. Rybka took 1^st place with a score of 5.5 out of 7.

In February 2006, Rybka won at CCT8 with a score of 8 out of 9.

In April 2006, Rybka 1.1 took 1^st place at the PAL/CSS Freestyle main tournament . In the final tournament, Rybka tied for 2^nd, behind Hydra.

In May 2006, Rybka took 1^st at the 6^th Leiden ICT with a score of 8.5 out of 9.

In May 2006, Rybka, playing under the name Rajlich, tied for 2^nd (with Shredder)at the 14^th World Computer Chess Championship in Turin, Italy. The event was won by Junior.

In June 2006, Rybka, playing under the handle Rajlich, tied for 1^st (with Intragrand) at the 2006 PAL/CSS Freestyle main tournament. It then took clear 1^st place in the final, a point ahead of the 2^nd place finisher.

In June 2006, the Swedish Chess Computer Association, Svenska schackdatorfoereningen (SSDF) computer rating list was released. Top ranked Rybka 1.2 256MB Athlon 1200 MHz was rated with an estimated Elo rating of 2902. It was the first time a program on the list has passed the 2900 mark.

In the 2006 Dutch open computer chess championship, Rybka 2.2 took 1^st place with a score of 9 out of 9.

In December 2006, Rybka took 1^st at the 16^th International Paderborn Computer Chess Championship, with a score of 6.5 out of 7.

In February 2007, Rybka won the CCT9 event with a score of 6 out of 7.

In May 2007, Rybka took 1^st at the 7^th Leiden ICT with a score of 7.5 out of 9.

In May 2007, a new chess engine called Strelka (Russian for “arrow”) was introduced, written by Yuri Osipov. It was alleged that it was a reverse-engineered clone of Rybka 1.0 beta. Osipov, however, stated that Strelka was based on Fruit, not Rybka. When Strelka 2.0 beta was released, it included the source code. Rajlich claimed that the source code was his own and he wanted to re-release the program under his own name, although he never did. Fruit author Letouzey statd that Strelka 2.0 beta was a derivative of his Fruit program.

In June 2007, Rybka won the 15^th World Computer Chess Championship, held in Amsterdam, with the score of 10 out of 11 (defeating Shredder in the last round). 2^nd place went to the USA program Zappa, programmed by Anthony Cozziem. 3^rd place went to Look. Defending champion Junior, nor Fritz, did not participate.

In June 2007, Rybka, playing under the handle Rajlich, won the PAL/CSS Freestyle final.

In August, 2007, Grandmaster Joel Benjamin played a match with Rybka in which Rybka played without one of its pawns (pawn odds). Rybka won the match 4.5 - 3.5 (2 wins, 1 loss, 5 draws for Rybka).

In 2007, Rybka won the Dutch open computer chess championship with a score of 8 out of 9.

In September 2007, Zappa defeated Rybka in a match, 5.5-4.5. Rybka moved a pawn to avoid a draw under the 50-move rule, and lost after 180 moves.

In 2007, Rybka 2.3.1 Arena 256MB Athlon 1200 MHz was rated #1 in the world by SSDF with an estimated Elo rating of 2935.

In 2007, Rybka won the computer Chess960 tournament in Mainz.

In December, 2007, Hiarcs won over tie breaks against Rybka, with a score of 5.5 out of 7 at the 17th International Paderborn Computer Chess Championship.

In January 2008, Rybka tied for 1^st at CCT10 with the score of 5.5 out of 7.

In January, 2008, Rybka defeated GM Joel Benjamin with a 6-2 score. Joel had White in every game. Also, every draw was scored as a win for Benjamin.

In March 2008, Rybka played an 8-game match against Grandmaster Roman Dzindzichashvili with pawn and move odds. The result was a tie, 4-4 (2 wins, 4 draws, 2 losses). Dzindzichashvili had White every game and Rybka played without one of its pawns in every game.

On September 26, 2008, the SSDF computer rating list was released with Deep Rybka 3.2 GB Q660 2.4 GHz leading with an estimated Elo rating of 3228.

In September-October 2008, Rybka won the 16^th World Computer Chess Championship, held in Beijing, China, scoring 8 out of 9 (7 wins, 2 draws, no losses). Hiarcs took 2^nd and Junior took 3^rd.

In November 2008, Rybka won the 27^th Open Dutch Computer Chess Championship, held in Leiden, with a score of 9 out of 9.

In March 2009, Rybka won CCT11 with the score of 7.5 out of 9.

In May 2009, the chess program IPPOLIT was release by a team of anonymous programmers. In October 2009, Rajlich stated that IPPOLIT was a decompiled version of Rybka.

In May 2009, Rybka won the 17^th World Computer Chess Championship, held in Pamplona, Spain, with the score of 8 out of 9. There was a 3-way tie for 2^nd between Shredder, Junior, and Deep Sjeng.

In 2009, Deep Rybka 3.2 GB Q660 2.4 GHz was ranked #1 in the world by the SSDF with an estimated Elo rating of 3232.

During 2009-10, Rybka won the World Computer Speed Chess Championship.

On March 21, 2010, the latest SSDF computer rating list was released. Deep Rybka 3.2 GB Q660 2.4 GHz was ranked #1 with a rating of 3227.

The 18^th World Computer Chess Championship was held in Kanazawa, Japan in 2010 and won by Rybka, followed by Rondo and Thinker. The blitz tournament was also won by Rybka with 8/9 score. Rajlich received 1,000 euros ($1,593 USD) for his victory.

In May 2010, Rybka won the 30thInternational Computer Chess Tournament in Leiden with a score of 8 out of 9.

Rybka 4 was released on May 26, 2010. Rybka 4 is a normal UCI engine, without copy protection.

In January 2011, Rybka took 2^nd, behind Houdini, in the Thoresen Computer Engines Competition.

In 2011, the International Computer Games Association (ICGA) accused Rajlich of plagiarizing two other programs, Crafty and Fruit, without acknowledging their code. The formation of the IGCA Clone and Derivation Investigation Panel concluded that Rybka was using cloned computer engines from Crafty and Fruit. ICGA President IM David Levy has addressed these allegations at ChessVibes and has created a programmers forum to decide the3 merits of the allegations. Did Rajlich inject Rybka with performance-enhancing code?

14 well-known chess programmers have concluded that Rybka 1.0 beta (the first strong Rybka version) was directly derived from the computer program Fruit, authored by Fabien Letouzey. Rajlich was accused of failing to comply with the IGLA rule that each computer chess program must be the original work of the entering developer.

On June 29, 2011, after a 5-0 vote, Rybka was stripped of its titles, and Rajlich has now been banned for life in playing in computer chess championships. The ICGA disqualified and banned Rybka ants its programmer, Rajlich, from previous and future World Computer Chess Championships. Rajlich has denied using other code, saying that Rybka is 100% original at the source code level.

Further allegations have been made that Rajlich violated the Gnu Public License (GPL ) based on a decompilation effort by chess programmer Zach Wegner.

The ICGA has demanded that Rajlich return the four replicas of the Shannon trophy (World Computer Championshop Trophy) and prize money of the World Computer Chess Championships of 2007, 2008, 2009, and 2010.

In 2006, the program “Rajlich” took 2^nd-3^rd place in the world computer chess championship. That has now been annulled. 2^nd place now goes to Shredder and 3^rd place goes to Zappa.

The 1^st places and World Computer Chess Champion titles that was awarded to the program Rybka from 2007 through 2010 are all annulled, The revised titles are: 2007 – Zappa (World Champion); 2008 – Hiarcs (World Champion); 2009 – Junior, Shredder, and Deep Sjeng (Joint World Champions); 2010 – Rondo and Thinker (Joint World Champions.