Rybka

Rybka (Czech: fishes ) has been considered the strongest chess program in the world. Chief developer of the chess engine Rybka, which is available in a 32- bit and 64- bit version is the International Master Vasik Rajlich. The team includes or included also Rajlichs wife Iweta, born Radziewicz, which bears the title of a woman Grand Master, the Grand Master Larry Kaufman, who worked on the valuation functions of the program, as well as Jeroen Noomen who has designed a tailor on Rybka's playing style opening book.

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

Revision history

A beta version of Rybka 1.0 made ​​in December 2005 by outstanding test results for sensation. They played better than all existing commercial engines. In March 2006, the commercial version 1.2 was released, to which it gave in May 2006 as a result some updates up to version 1.2f. Since version 2.0 ( June 2006), several processors are supported. The version 2.3.2a mp ( supports multi-core processors ) is now available for free. Under the name Rybka Winfinder there was a modified version of the " attack on the king " stronger tactically and especially when the subject than the standard version of Rybka, but plays weaker overall in a direct comparison, as well as a version of Rybka 2.3 LK, which in terms of character assessment on the basis of proposals Larry Kaufman has been modified.

Version 3 was released on 6 August 2008. Along with the standard engine and additional versions of Rybka Rybka Dynamic Human shipped each with a different style of play, as well as a version for Chess960. The "Dynamic " version rated material of low and weighted positional factors higher, the " human " version includes Larry Kaufman developed algorithms which, although had a slightly negative impact on the skill level and were therefore not implemented in the standard version, but correspond to human experience.

Up to version 2 Rybka did not have a user interface, but was included as a UCI engine into popular chess frontends such as Arena, Chess Assistant, ChessBase or Shredder Classic. The program is distributed via download, and since July 2006 also on DVD from the Russian company Convekta. A separate interface for Rybka (aquarium ) was developed by Convekta for version 3. Rybka 3 is also marketed by the company ChessBase Fritz with a customized user interface. The official opening book for Rybka 3 are sold separately written and Rybka Chessbase and ChessOK by Jeroen Noomen. The opening book for Rybka 4 by Jiri Dufek comes.

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

Rybka was long regarded as the most powerful engine in the world and led the world's most important ranking lists ( CCRL and SSDF ), but was then ousted from this place by Houdini. Right now ( 9/2012 ) also play the freeware program Critter 1.6a and the open-source program Stockfish, available for Windows / Mac / Linux / Android, at the level of the current version of Deep Rybka 4.1.

Tournament Results

Computer chess tournaments

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

In May 2007, the victory was followed by the ICT7 in Leiden, in June with version 2.3.2 of winning the 15th World Computer Chess Championship in Amsterdam ( 10 points from 11 games, no defeat ). In June won the Rybka team (IM Iweta Rajlich, IM Vasik Rajlich and Rybka ) the 6th PAL / CSS Freestyle Tournament. In August Rybka won in Mainz Chess960 Computer World Championship. In October Rybka won at the 27th Dutch Open Computer Chess Championship in Leiden and the 2nd Americas Computer Chess Championship. When IPCCC 2007, Rybka had to admit defeat (both scored 5.5 / 7 points) because of poorer fine rating HIARCS.

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 World Computer Chess 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 won the 28th Open Dutch Computer Chess Championship in Leiden with 9 points from 9 games in November.

The year 2009 began with a victory at CCT 11 ( both flash and rapid chess ) in March. A cluster was used with 52 cores and used for the first time when one of CCT Jeroen Noomen. In May 2009, Rybka won with 8 points from 9 games, the 17th World Computer Chess Championship in Pamplona. In this tournament, the hardware was limited to a maximum of 8 cores, Rybka running on an Intel Xeon W5580 3.2GHz. The Blitz Championship was also won by Rybka on the same hardware. In addition to the World Cup and the Olympics in Pamplona was played in which was no hardware limitation. Rybka running on a cluster with 9 PCs and won with 5 points from 5 games. In August Rybka won in Mainz Computer Chess World Championship in the 960 with 14.5 points from 16 matches, and in October the 29th Open Dutch Computer Chess Championship in Leiden with 7.5 points from 8 games.

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

Results against human players

In January 2006, Rybka won a match against the Chilean Grandmaster Iván Morovic (Elo 2551 ) with 1.5:0.5. In March Rybka ( ELO section 2460 ) in Santiago de Chile took part in a tournament of Class IX and won superior with 9 points from 10 matches (8 wins, 2 draws). In October and December Rybka won two discharged about chess server rapid games against Grandmaster Larry Christiansen, respectively.

In March 2007, Rybka won a handicap match against Jaan Ehlvest with 5.5 to 2.5, wherein the program played in each of the 8 games with White and each pretending a farmer. In July Ehlvest came again against Rybka, this time he had in every game White and the opening book of the program was limited to three trains. He also had twice the reflection available. The match ended in favor of Rybka 4.5 to 1.5. In August Rybka won a competition with farmers default against Joel Benjamin with 4.5 to 3.5. Unlike the first match against Ehlvest the program played alternately with white and black, in each case the peasants were d2, c7, b2, a7, e2, f7, h7 and g2 given. In September Rybka defeated Mexico in the Grandmaster Robert Fontaine, who had white in every game, in rapid chess 2-0.

In January 2008, Rybka played another match against Joel Benjamin, who in all eight games had white and got a draw counted as profit. The result was 6-2 in favor of Rybka. In March 2008, a match ended in eight games against Grandmaster Roman Dzindzichashvili in which Rybka pretending a farmer and always had black, with 4-4. In July there was another match against Dzindzichashvili, in which the computer each with black farmers pretended in four games f7. The cooling-off control was 30 minutes per game plus 20 seconds per train. Rybka won the competition with 2.5 to 1.5 ( one win, three draws). In September Rybka lost a match on eight games against Vadim Milov, who at this time had an Elo rating of 2705, with 3,5:4,5. In this two normal games in which White had Milov, played two games with default f7 pawn and train as well as four games with the default quality ( a1 rook and knight b8 ). The thinking time was 90 minutes per game plus 30 seconds per train. Rybka won a game with black, Milov one each with farmers and quality setting, five games ended in a draw.

Playing style and features

As with many chess programs also Rybka's playing style has changed over the course of its development. Were versions 1.0 up to and including 2.3.2a especially as positionally very mature, but with smaller tactical weaknesses, so this is no longer true since the release of version 3. Rybka 3 has been significantly improved tactically and especially in the attack on the king very strong and compared to previous versions.

Rybka's evaluation function is very comprehensive and balanced, which tend to be objective and reliable position leads Reviews.

For technical programming 2.3 some evaluation functions have been removed for ease of playoffs with 6 or fewer stones since Rybka, whereby the use of Nalimov endgame databases just in the analysis may be useful. However, the real skill level increase by the use of endgame databases is according to the author in the low double-digit ELO range.

Controversy surrounding plagiarism software

There are allegations that the first version of Rybka is based on the program code from Fruit. Fruit 2.1 was released in June 2005 under the GNU General Public License, six months later published Rajlich the beta version of Rybka. The evaluation functions of the two programs have many similarities. Rajlich stated that although he had taken ideas from Fruit, its program code but written independently. In June 2011, Rybka was excluded from future tournaments of the International Computer Games Association and its world title revoked, what drew a complaint with the Ethics Commission, the World Chess Federation FIDE after themselves.

Rajlich accused his hand several programmers, their programs were based on decompiled versions of Rybka 3