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The chess engine IPPOLIT was released in October 2009 with its source code. Vasik Rajlich has alluded that IPPOLIT may be a [[decompiler|decompiled]] version of Rybka, and that the people involved kept him informed of their progress via email.<ref>[http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?tid=12995 Official statement on Ippolit]</ref>
The chess engine IPPOLIT was released in October 2009 with its source code. Vasik Rajlich has alluded that IPPOLIT may be a [[decompiler|decompiled]] version of Rybka, and that the people involved kept him informed of their progress via email.<ref>[http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?tid=12995 Official statement on Ippolit]</ref>

IPPOLIT and derivatives have been refused entry to the two most active computer chess rating lists, the CCRL<ref>{{cite web|url=http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?f=7&t=4866|title=IPPOLIT series|date=13 January 2010|publisher=CCRL Discussion Board|accessdate=19 March 2010}}</ref><ref>{{cite web|url=http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?f=7&t=4895|title=Clones?|date=1 February 2010|publisher=CCRL Discussion Board|accessdate=19 March 2010}}</ref> and the CEGT.<ref>{{cite web|url=http://cegt.foren-city.de/topic,353,-ippolit-series.html|title=IPPOLIT series|date=15 January 2010|publisher=CEGT Forum|accessdate=19 March 2010}}</ref> In addition, they were also explicitly denied entry to all future [[Internet Computer Chess Tournament]]s (CCT).<ref>{{cite web|url=http://talkchess.com/forum/viewtopic.php?t=32201|title=CCT 12: Registration expectations|last=Skinner|first=Peter|date=29 January 2010|publisher=TalkChess.com computer chess forum|accessdate=20 March 2010}}</ref>


== References ==
== References ==

Revision as of 00:05, 20 March 2010

This article is about the chess computer. For other uses, see Rybka (disambiguation).
Rybka
Developer(s)Vasik Rajlich
Stable release
3 / August 6, 2008[1]
Operating systemWindows
TypeChess engine
LicenseProprietary
Websiterybkachess.com

Rybka is a computer chess engine designed by International Master Vasik Rajlich. As of February 2010, Rybka is top-rated on chess engine rating lists[2][3][4][5] (where it is usually rated over 100 Elo points above the second place) and has won many official Computer Chess Tournaments including the 2007, 2008, and 2009 World Computer Chess Championships. Rybka supports both single processor and symmetric multiprocessing (SMP) systems.

Name

The word rybka means little fish in Polish and Czech languages, where it is IPA: [ˈrɪpka]. Vasik Rajlich was once asked in an interview by Alexander Schmidt, "Did you choose the name Rybka because your program always slipped out of your hands like a little fish?" He replied, "As for the name Rybka - I am sorry but this will remain my private secret."[6]

Playing strength

Rybka 2.2n2 (which is available as a free download) has been rated at 3110 Elo[7] on 4 CPUs, and Rybka 3 is approximately 100 Elo stronger than 2.2n2[8]. Current versions of Rybka use multiple processors, yielding an estimated increase of 50 Elo per doubling of processors.[9]

On September 26, 2008, the latest SSDF rating list was released, with Deep Rybka 3 in first place in the rankings with a rating of 3238.

Rybka's search is considered one of its main advantages over rival programs while its efficient design as a bitboard engine lends it an extra 60% processing efficiency when run in 64-bit mode, yielding approximately 40 additional Elo.

Internals

Rybka is a closed-source program, but still some details have been revealed: Rybka uses a bitboard representation,[10] and is an alpha-beta searcher with a relatively large aspiration window.[11] It uses very aggressive pruning, leading to imbalanced search trees.[12] The details of the evaluation function are unknown, but since version 2.3.1 it has included work by GM Larry Kaufman on material imbalances, much of which was worked out in a series of papers in the 1990s.[13]

Fruit GPL chess engine controversy

Rybka has been accused of being based on Fruit, but Rajlich has denied this categorically.[14] Further allegations of violating the GPL have been brought forward by chess programmer Zach Wegner based on a new decompilation effort and a one year study of the Rybka 1.0 executable.[15] Vas has since declined to respond to these allegations.[16]

Team

Iweta and Vasik Rajlich

The Rybka team is unusual among computer chess teams in that several of its main members are strong chess players: Vasik Rajlich, the main author of Rybka is an International Master (IM). GM Larry Kaufman is the 2008 Senior Chess World Champion, and is (from version 2.3) in primary charge of the evaluation function. Iweta Rajlich, Vasik Rajlich's wife and the main Rybka tester is a Women's GM (WGM) and IM. Jeroen Noomen (who used to work on Rebel) and Dagh Nielsen are the authors of its opening book – the latter is one of the world's top freestyle chess players.

History

Vasik Rajlich started working on his chess program at the beginning of 2003. The first Rybka beta was released on December 2, 2005.

Tournament participations

In 2005, from December 27 to December 30, Rybka participated in the 15th International Paderborn Computer Chess Championship. Rybka won the tournament with a score of 5½ points out of 7, ahead of other engines such as Gandalf, Zappa, Spike, Shredder and Fruit.

On CCT8 from February 25 to February 26, Rybka won with a score of 8 out of 9, going undefeated. In the April 2006 PAL/CSS Freestyle main tournament, an unaided Rybka 1.1 took first place. In the final tournament, Rybka 1.1 finished in second and third place, behind Hydra. In the 6th Leiden ICT in May 2006, Rybka won with a score of 8½ out of 9, ahead of Sjeng, Gandalf and Shredder. At the 14th World Computer Chess Championship in Turin, Italy in May 2006, Rybka, playing under the name Rajlich, finished second, tied with Shredder, after Junior, the winning 2006 World champion. In the June 2006 PAL/CSS Freestyle main tournament, the Rybka team, playing under the handle Rajlich, tied for first place with Intagrand. In the final, the Rybka team took clear first place, a point ahead of the field. All 8 qualifiers for to the final were Rybka users. In the 2006 Dutch open computer chess championship, Rybka 2.2 finished in first place with a perfect score of 9 out of 9.[17] In December 2006, Rybka participated in the 16th International Paderborn Computer Chess Championship. Rybka won the tournament with a score of 6½ points out of 7.[18]

In February 2007, Rybka participated in the CCT9 and won with 6/7.[19] In the 7th Leiden ICT in May 2007, Rybka won with a score of 7½ out of 9, ahead of Zappa and HIARCS.[20] Rybka won the 15th World Computer Chess Championship in June 2007 with a score of 10 out of 11. The Rybka team, playing under the handle Rajlich, won the June 2007 PAL/CSS Freestyle final with a score of 6/9. Later that year it won again the Dutch open computer chess championship, scoring 8/9.[21]

In January 2008, Rybka tied for first place in CCT10 with 5.5/7.[22] In October 2008, Rybka won the 16th World Computer Chess Championship, held in Beijing, China, scoring 8/9. A month later Rybka won the 27th Open Dutch Computer Chess Championship, held in Leiden, scoring a perfect 9/9.[23]

In March 2009, Rybka won CCT11 with 7.5/9[24] and the 17th World Computer Chess Championship, held in Pamplona, Spain, with a score of 8/9.[25]

Odds matches versus grandmasters

Whilst Rybka has won a match with GM Jaan Ehlvest which involved giving pawn odds to the human, GM Larry Kaufman of the Rybka team has pledged his own money to a human GM who can beat Rybka in a six-game match without material odds. GM Jaan Ehlvest was again chosen to play Rybka, getting twice the thinking time and white every match, with Rybka having only a three-move opening book, limited (512MB) hash size, and no endgame tablebases (the match being dubbed "Everything but a pawn"). The match ended 4.5-1.5 after three Rybka wins and three draws.[26]

In March 2007, Rybka played an eight-game match against GM Roman Dzindzichashvili with pawn and move odds, from March 3 to March 8. The result was 4-4, after two Rybka wins, four draws and two losses.[27]

In September 2008, Rybka played an odds match against Vadim Milov, its strongest opponent yet in an odds match. (Milov at the time had an Elo rating of 2705, 28th in the world). The result was a narrow victory to Milov: In two standard games (Milov played White, no odds), Rybka won 1½-½. Milov won 1½-½ when given pawn-and-move, and 2½-1½ (1 win, 3 draws) when given exchange odds but playing Black.[28]

Zappa match

In September 2007, Zappa defeated Rybka in a match, 5½-4½. A key game was the 180-move fourth game [29], which was approaching a draw under the 50-move rule. However, due to a feature of the Rybka engine, at move 109 it moved a pawn to avoid a draw (even though Zappa could, and did, immediately take the pawn), thus resetting the counter for that rule. The loss of the pawn eventually allowed Zappa to whittle away Rybka's defenses and win the game.[30]

Version 3

While previous versions of Rybka were released exclusively by Convekta, Rybka 3 was released by both Chessbase and Convekta.[31] Although still a UCI engine, Rybka 3 has extra features when run under the ChessBase and Convekta user interfaces.[1] In an interview with Frank Quisinsky, Vasik Rajlich revealed plans for a future GUI that would "properly display chess knowledge to the user" most likely in the form of graphical evaluation of the pieces on the board. The GUI, named Aquarium, has been released by ChessOK (formerly known as Convekta).[32]

Chess960 support was implemented for the Chess Classic Mainz 2007, where Rybka subsequently won the computer Chess960 tournament.[33][34]

There were many general playing strength improvements, including multiprocessor performance improvements, increased search efficiency, and better position evaluation. Three engine styles are supported: optimum, human, and dynamic. The opening book is now sold as a separate product.[1] Chess engine rating lists which have already published results for Rybka 3 show it topping the rating lists ahead of the previous version of Rybka, sometimes by as much as 100 ELO points.[35]

Future release plans

The following features have been confirmed for future versions:

  • Native Linux support has been confirmed without a specific date. Release plan for platforms other than Windows is expected to come after Rybka 3.0 is finished.[36] Rybka does, however, run under Wine, and 64-bit Rybka runs under both Linux and Mac OS X using an experimental, Rybka-specific translation layer called microwine.[37]
  • Support for Pocket PCs and similar mobile devices were announced in 2007.[38] But products for Pocket PCs and similar mobile devices were never released.

Rajlich has asserted that Rybka will continue to use open protocols, both for normal operations as well as for the data presented by the Rybka 3 GUI.[citation needed]

Strelka controversy

In May 2007, a new chess engine called Strelka appeared on the scene, claimed to be written by Yuri Osipov. Soon, there were allegations that Strelka was a clone of Rybka 1.0 beta, in the sense that it was a reverse-engineered and slightly modified version of Rybka.[39] Several players found Strelka to yield identical analysis to Rybka in a variety of different situations, even having the same bugs and weaknesses in some cases. Osipov, however, stated repeatedly on discussion boards that Strelka was based on Fruit, not Rybka, and that any similarities was either because Rybka also was based on Fruit, or because he had tuned the evaluation function to be as close to Rybka as possible.[40][41]

With the release of Strelka 2.0 beta, source code was included. Rajlich stated that the source made it "obvious" that Strelka 2.0 beta was indeed a Rybka 1.0 beta clone, although not without some improvements in certain areas. On basis of this, he claimed the source as his own and intended to re-release it under his own name,[42] although he later decided not to do so. He also made allegations that "Yuri Osipov" was a pen name.

However, according to Victor Zakharov (Convekta company) in his review for Arena chess website, he said "I consider that Yuri Osipov (Ivanovich) is real name. He didn't hide it. However I can't state this with 100% assurance." And he also has some contact with Yuri Osipov for development of mobile platforms chess program. [43]

IPPOLIT controversy

IPPOLIT, RobboLito, Igorrit, IvanHoe and Firebird is a series of strong open source chess programs, developed by a team of anonymous programmers who call themselves the Decembrists.[44][45]

The chess engine IPPOLIT was released in October 2009 with its source code. Vasik Rajlich has alluded that IPPOLIT may be a decompiled version of Rybka, and that the people involved kept him informed of their progress via email.[46]

IPPOLIT and derivatives have been refused entry to the two most active computer chess rating lists, the CCRL[47][48] and the CEGT.[49] In addition, they were also explicitly denied entry to all future Internet Computer Chess Tournaments (CCT).[50]

References

  1. ^ a b c "Rybka 3 Release Notes". August 6, 2008. Retrieved 2008-08-07.
  2. ^ "CCRL 40/40 - Pure list". February 5, 2010. Retrieved 2010-02-13.
  3. ^ "CEGT 40/20". Chess Engines Grand Tournament. February 7, 2010. Retrieved 2010-02-13.
  4. ^ "The SSDF Rating List". Swedish Chess Computer Association. September 20, 2009. Retrieved 2010-02-13.
  5. ^ "Bayesian Elo Ratinglist WBEC Ridderkerk edition 1 - 16". September 22, 2009. Retrieved 2010-02-13.
  6. ^ http://www.superchessengine.com/vasik_rajlich.htm
  7. ^ http://www.rybkachess.com/index.php?auswahl=Demo+version
  8. ^ http://www.computerchess.org.uk/ccrl/4040/
  9. ^ FAQ for Rybka 2.0-2.2n2
  10. ^ rybka source code
  11. ^ Rybka search
  12. ^ Rybka search
  13. ^ Rybka @ Amsterdam 15th WCCC
  14. ^ Is Rybka a derivative of Fruit?
  15. ^ https://webspace.utexas.edu/zzw57/rtc/eval/eval.html
  16. ^ http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?pid=205163;hl=
  17. ^ Rybkachess.com
  18. ^ 17th International Computer Chess Championship - IPCCC 2007 in Paderborn
  19. ^ Rybka by Vasik Rajlich is CCT9 Champion
  20. ^ International CSVN Tournament 2007
  21. ^ Computerschaak - ONK 2007
  22. ^ CCT10 Final Scoreboard
  23. ^ Rybka Open Nederlands Kampioen 2008
  24. ^ CCT11 Final Scoreboard
  25. ^ 7th World Computer Chess Championship
  26. ^ Rybka vs Ehlvest II - information center
  27. ^ Rybka vs Dzindzichashvili - information center
  28. ^ The Milov vs. Rybka Handicap Match, Chessbase, September 24, 2008
  29. ^ http://www.chessgames.com/perl/chessgame?gid=1473884
  30. ^ http://rybkaforum.net/cgi-bin/rybkaforum/topic_show.pl?tid=2235
  31. ^ Chessvine Article, "A 'Little Fish' (Rybka) in Corporate Waters"
  32. ^ Rybka Aquarium: Interview with the Developers
  33. ^ Rybka in Chess Classic Mainz 2007, Chess 960
  34. ^ "CCM7 - 3. Livingston Chess960 Computer-Weltmeisterschaft". Chess Tigers. Retrieved 2007-08-22.
  35. ^ CEGT
  36. ^ http://chessok.com/?p=512
  37. ^ (Experimental) 64-bit Rybka on Linux
  38. ^ I want know if rybka will be developed for pocketpc
  39. ^ Strelka 1.0 x32:Rybka clone?
  40. ^ Strelka = Rybka 1.0
  41. ^ osipovs arguments about strelka
  42. ^ Strelka 2.0
  43. ^ http://www.playwitharena.com/directory/reviews.htm
  44. ^ http://ippolit.wikispaces.com/
  45. ^ http://www.chesslogik.com/FireBird.htm
  46. ^ Official statement on Ippolit
  47. ^ "IPPOLIT series". CCRL Discussion Board. 13 January 2010. Retrieved 19 March 2010.
  48. ^ "Clones?". CCRL Discussion Board. 1 February 2010. Retrieved 19 March 2010.
  49. ^ "IPPOLIT series". CEGT Forum. 15 January 2010. Retrieved 19 March 2010.
  50. ^ Skinner, Peter (29 January 2010). "CCT 12: Registration expectations". TalkChess.com computer chess forum. Retrieved 20 March 2010.
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