Home * Engines * Rybka
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Rybka,
a chess engine by primary author Vasik Rajlich, since 2007 dominating and reigning World Computer Chess Champion and holder of the Shannon Trophy, winning the WCCC 2007 [1] , WCCC 2008, WCCC 2009 and WCCC 2010, but in June 2011 disqualified by the ICGA from all previous and future World Computer Chess Championships [2] . Rybka further won various IPCCC, Dutch Open Computer Chess Championships, International CSVN Tournaments and on-line tournaments such as CCT Tournaments and ACCA Americas' Computer Chess Championships. Rybka is a standalone chess engine supporting the UCI protocol.
Rybka 4 Logo [3]

Screenshots

external image rybka4-04.jpg
ChessBase GUI, 3D boards with scoresheet and analysis board [4]

external image 7.png
Deep Rybka 4 Aquarium by ChessOK [5]

Team

The Rybka team consists of primary author and International Master Vasik Rajlich, supported by Grandmaster and evaluation expert Larry Kaufman (Rybka 3), Rybka's main tester and Women's GM (WGM) and IM Iweta Rajlich, the opening book authors Jeroen Noomen, Dagh Nielsen, Jiří Dufek and Nick Carlin, as well as Rybka primary tournament operator Hans van der Zijden, hardware expert Lukas Cimiotti and Webmaster and Webdesigner Felix and Christoph Kling [6] .

Versions

Vasik Rajlich started developing Rybka in about 2003, and worked full-time on it since 2005. The appearance of the free Rybka 1 beta [7] [8] [9] and the first commercial version, Rybka 1 [10] end of 2005 was a sensation, and Rybka soon became the dominating program leading rating lists by a huge margin [11] [12] . Rybka 3 was developed in collaboration with Larry Kaufman, the most recent and strongest version Rybka 4 and the parallel version Deep Rybka 4 appeared in April 2010, market as standalone chess engine from RybkaChess.com [13] , from ChessOK optional with the Aquarium GUI [14] , or from ChessBase packaged with the Fritz GUI [15] . The demo version Rybka 2.3.2a can be downloaded for free [16] .

Achievements

[17]
Year
Tournament
Rank/From
Title/Remarks
2004
CCT6
50/54

2005
IPCCC 2005 b
1/12

2006
CCT8
1/38


ICT 2006
1


WCCC 2006
3/18
as Rajlich, disqualified 2011

DOCCC 2006
1


IPCCC 2006
1/10

2007
ACCA 2007
1/16


CCT9
1/54


ICT 2007
1


WCCC 2007
1/12
World Computer Chess Champion, disqualified 2011

DOCCC 2007
1/14


IPCCC 2007
2/10

2008
ACCA 2008
1/18


ICT 2008
1


WCCC 2008
1/10
World Computer Chess Champion, disqualified 2011

DOCCC 2008
1/10

2009
ACCA 2009
1/12


WCCC 2009
1/10
World Computer Chess Champion, disqualified 2011

DOCCC 2009
1/9

2010
ICT 2010
1/14


WCCC 2010
1/10
World Computer Chess Champion, disqualified 2011

DOCCC 2010
1/20

2012
ICT 2012
1/8


Program Internals

Rybka is a bitboard engine, first versions rotated, Rybka 4 apparently magic bitboards for sliding piece attack and move generation. Vasik once posted a snippet of Rybka source-code, a typical bitboard serialization loop to generate white knight captures [18] .
for (bb_t knights = Board.pieces [WN]; knights; knights &= knights-1)
{
    int knight_sq = bit_scan (knights);
    for (bb_t captures = knight_moves [knight_sq] & opponent_pieces; captures; captures &= captures - 1)
    {
        int capture_sq = bit_scan (captures);
        *moves ++ = move (knight_sq, capture_sq);
        *values++ = Board.sq [capture_sq] * 256 + 192;
    }
}
Due to the disputed open source engines Strelka 2.0 and later Ippolit, which accordant to Vasik Rajlich were both based on or heavily influenced by re-engineered Rybka executables [19] [20] , other implementation details were released to the public, such as material- and material imbalance tables, aggressive LMR, razoring [21] and some variation of singular extensions [22] . Zach Wegner elaborated on evaluation issues, and compared Rybka 1 beta with Fruit's evaluation [23] [24] , continued by former anonymous author "BB+" alias Mark Watkins in February 2011 [25] .

Release Dates

  • Rybka 1.0 beta : 2005-12
    Rybka 1.0 :
    Rybka 1.1 : 2006-04
    Rybka 1.2 : 2006-06
    Rybka 1.5 :
    Rybka 1.6.1 :
    Rybka 2.0 :
    Rybka 2.2 : 2006
    Rybka 2.2n2 : 2006-12
    Rybka 2.3 : 2007-01
    Rybka 2.3.1 : 2007-02
    Rybka 2.3.2a : 2007-06
    Rybka 3 : 2008-08
    Rybka 4 : 2010-05
    Rybka 4.1 : 2011-3

Controversies

Rybka 1.0 and Fruit

Rajlich's interpretation of nodes and depth [26] [27] [28] [29] [30] , and the controversy about Strelka [31] [32] raised suspicions about the initial origin of Rybka 1.0 [33] [34] , but Vasik Rajlich categorically denied Rybka 1.0 was based on Fruit [35] [36] , as mentioned by Chrilly Donninger in 2005 [37] after early rumors [38] and questions [39] arose.

Vasik Rajlich's most quoted statement in these discussions was probably from an interview in uciengines.de, December 20, 2005 [40] :
Yes, the publication of Fruit 2.1 was huge. Look at how many engines took a massive jump in its wake: Rybka, Hiarcs, Fritz, Zappa, Spike, List, and so on. I went through the Fruit 2.1 source code forwards and backwards and took many things.
...
Anyway, if I really had to give a number - my wild guess is that Rybka would be 20 rating points weaker had Fruit not appeared.

Ippolit

The appearance of the Ippolit open source program by pseudonymous authors in May 2009, and Rajlich's claim it is a clone of Rybka 3 [41] without any substantiation and evidence, caused further discussions [42] .

Open Letters

In January 2011, Fabien Letouzey confirmed that Strelka, the allegedly clone of Rybka, was not a verbatim copy of the source code from Fruit, but a bitboard re-write of Fruit with some other ideas, and not just an extraction of a couple of ideas [43] [44] [45] .

On February 19, 2011 ICGA president David Levy broached on cloning issues in a ChessVibes column [46] . In March 2011, following computer chess programmers signed an open letter to David Levy, Jaap van den Herik and the board of the ICGA, to support the claim Rybka 1.0 beta and subsequent versions were allegedly derivatives from Fabien Letouzey’s program Fruit 2.1:

The letter was published in the private ICGA Investigations Wiki [49] and elsewhere [50] [51] [52] . The German sites Heise online [53] and Spiegel Online broached the issue [54] .

Pre-Beta Rybka and Crafty

In February and March 2011, evidence was found by Zach Wegner and Mark Watkins that pre-Beta Rybka, which played the CCT6 in January 2004, and competed in tournaments of Engine Rating Lists such as ChessWar [55] [56] and Le Fou numérique [57] , contain a substantial amount of Crafty code [58] , confirmed by Robert Hyatt [59] [60] . Beside other evidence there are the known bugs in the old Crafty code (if ms == 99999) [61] that caused El Chinito by primary author Eugenio Castillo Jiménez to be exposed as a clone [62] [63] .

Disqualification

In June 2011, the ICGA has disqualified and banned Rybka and its programmer Vasik Rajlich from previous and future World Computer Chess Championships. The ICGA accuses Rajlich of plagiarizing two other programs, Crafty and Fruit, and demands that he returns the trophies and prize money of the World Computer Chess Championships in 2007, 2008, 2009 and 2010 [64] .

In August 2011, the board of the Dutch Computer Chess Federation (CSVN) declared the most serious doubts as to the rightfulness of ICGA's decision. Therefore, they have chosen not to abide by their sanctions against Rybka [65] , see ICGA Investigations

See also


Publications


Forum Posts

2004

2005

2006

2007

2008

2009

2010

2011

2012


External Links

Rybka


Controversy


References

  1. ^ Bulletin Day 7 WCCC 2007 (ICGA Tournaments)
  2. ^ Rybka disqualified and banned from World Computer Chess Championships : ChessVibes by Peter Doggers, June 29, 2011
  3. ^ Rybka - for the serious chess player - Purchase Rybka
  4. ^ Rybka 4 is here – and stronger than ever, ChessBase News, May 31, 2010
  5. ^ ChessOK, Chess Shop from the Developers of Rybka 3 Aquarium
  6. ^ Rybka - for the serious chess player - Rybka team
  7. ^ Rybka 1.0 beta release - need testers by Vasik Rajlich, CCC, November 30, 2005
  8. ^ Rybka Beta 1.0 - Chess.com
  9. ^ New Chess Engine - Rybka v 1.0 Beta Readme, Dec 4, 2005
  10. ^ Rybka 1.0 Announcement by Vasik Rajlich, CCC, December 05, 2005
  11. ^ The SSDF Rating List
  12. ^ CEGT Quad Versions 40/120 (AMD 3500+/4200+)
  13. ^ Rybka - for the serious chess player - Purchase Rybka
  14. ^ Rybka & Aquarium - ChessOK shop
  15. ^ Chess software - Rybka 4 from ChessBase
  16. ^ Rybka - for the serious chess player - Download Rybka 2.3.2a
  17. ^ Rybka disqualified and banned from World Computer Chess Championships : ChessVibes by Peter Doggers, June 29, 2011
  18. ^ re: rybka source code by Vasik Rajlich, Rybka Forum, July 24, 2007
  19. ^ Strelka 2.0 by Vasik Rajlich, Rybka Forum, January 11, 2008
  20. ^ My recent correspondence with Vasik Rajlich by Sven Schüle, CCC, June 13, 2010
  21. ^ Re: Strelka 2.0 pg 4 by Anthony Cozzie, Rybka Forum, January 11, 2008
  22. ^ A question to Larry Kaufman, by Erik, Rybka Forum, December 30/31, 2009
  23. ^ Rybka/Fruit: evaluation by Zach Wegner
  24. ^ Re: What do you folks make of this ? by Chris Whittington, OpenChess Forum, June 27, 2010
  25. ^ Mark Watkins (2011). A comparison of Rybka 1.0 Beta and Fruit 2.1, pdf, February 24, 2011 Version
  26. ^ What Strelka tells about Rybka's nodecount and depth by Ernest Bonnem, CCC, July 09, 2007
  27. ^ Does Rybka Properly Count Positions Evaluated? by John L. Jerz
  28. ^ To Jeroen and interested minds, re. Tiger node count by Christophe Théron, CCC, August 15, 2008
  29. ^ Re: Question to Larry Kaufman about Rybka by Larry Kaufman, CCC, February 05, 2010
  30. ^ Node counting by BB+, OpenChess Forum, January 20, 2011
  31. ^ Strelka = Rybka 1.0 by DarkAvenger, Rybka Forum, July 07, 2007
  32. ^ Strelka 2.0 by Vasik Rajlich, Rybka Forum, January 11, 2008
  33. ^ Rybka 1.0 vs. Strelka by Zach Wegner, CCC, August 19, 2008
  34. ^ Questions for Vas by Zach Wegner, CCC, August 25, 2008
  35. ^ Re: Is Rybka a derivative of Fruit? by Vasik Rajlich, Rybka Forum, July 14, 2007
  36. ^ question to vas on similarity of rybka 1.0 to fruit by duncan, Rybka Forum, August 25, 2008
  37. ^ Rybka uses PVS and not MTD(f). Its no Fruit-Clone by Chrilly Donninger, CCC, December 12, 2005
  38. ^ Is Rybbka a fruit clone? by Ziad Haddad, CCC, December 06, 2005
  39. ^ Rybka - How much Fruit is inside? by Daniel Mehrmann, CCC, December 11, 2005
  40. ^ Rybka, a new age in Computerchess? Interview with: Vasik Rajlich from uciengines.de by Christopher Conkie, Michael Diosi, Frank Quisinsky & Alexander Schmidt, December 20, 2005
  41. ^ Official statement on [Deleted]? by Vasik Rajlich, Rybka Forum, October 21, 2009
  42. ^ I'm in doubt if RobboLito is a clone by Volker Pittlik, CCC, October 24, 2009
  43. ^ Fabien's open letter to the community by Tord Romstad, CCC, January 23, 2011
  44. ^ Fabien's open letter to the community by Tord Romstad, OpenChess Forum, January 23, 2011
  45. ^ The Chess Mind Blog - More Computer Chess Controversy
  46. ^ Attack of the clones : ChessVibes by David Levy, 19 February, 2011
  47. ^ In retrospect by Rebel, Rybka Forum, July 14, 2011
  48. ^ Apology to Vas by Rebel, Rybka Forum, August 17, 2011
  49. ^ ICGA Investigations Wiki
  50. ^ Programmers write open letter about Rybka-Fruit issue : ChessVibes by Peter Doggers, March 01, 2011
  51. ^ Open letter to the ICGA about the Rybka-Fruit issue by Harvey Williamson, Hiarcs Forum, March 01, 2011
  52. ^ Programmers Open Letter to ICGA on Rybka/Fruit by BB+, OpenChess Forum, March 01, 2011
  53. ^ Plagiatsvorwurf gegen Computerschach-Weltmeister, Heise online, March 01, 2011 (German)
  54. ^ Schach-Software Rybka - Programmierer vermuten Intelligenzklau by Frank Patalong, Spiegel Online, March 03, 2011 (German)
  55. ^ RYBKA 1.6.1 in Chess War V-VII
  56. ^ Re: Programmers Open Letter to ICGA on Rybka/Fruit by Olivier Deville, Openchess Forum, March 05, 2011
  57. ^ Le Fou numérique - Le Système du Suisse 3 - T
  58. ^ Re: Programmers Open Letter to ICGA on Rybka/Fruit by BB+, OpenChess Forum, March 05, 2011
  59. ^ Re: Programmers Open Letter to ICGA on Rybka/Fruit by Robert Hyatt, Openchess Forum, March 05, 2011
  60. ^ Rybka 1.6.1 by Robert Hyatt, Rybka Forum, March 13, 2011
  61. ^ Re: Programmers Open Letter to ICGA on Rybka/Fruit byBB+, OpenChess Forum, March 04, 2011
  62. ^ Re: Correction: List and ElChinito as Crafty clones, ... etc by Paul H, CCC, August 21, 2004
  63. ^ Open letter by Eugenio Castillo (ELChinito team) ... by Frank Quisinsky, CCC, August 28, 2004
  64. ^ Rybka disqualified and banned from World Computer Chess Championships : ChessVibes
  65. ^ Rybka and the ICGA, CSVN Computerschaak
  66. ^ BB's Rybka/Ippolit comparison by Zach Wegner, OpenChess Forum, June 13, 2010
  67. ^ Feb 12 version: Rybka 1.0 Beta / Fruit 2.1 document by BB+, OpenChess Forum, February 12, 2011
  68. ^ Rybka evidence recapitulation by BB+, OpenChess Forum, January 03, 2012
  69. ^ Part 1 covers Houdini, Rybka, Komodo, Stockfish, Critter, Naum, Chiron and Spike
  70. ^ Anthony Cozzie speaks about Rybka source code from Steve Lim / SuperSteve3d - Home, February 04, 2008
  71. ^ Why did the ICGA ignore this advice? by John Sidles, Rybka Forum, July 06, 2011
  72. ^ Re: A Big Thanks and a Small Update by John Sidles, Rybka Forum, January, 08, 2012
  73. ^ Voir dire from Wikipedia
  74. ^ Fruit 2.1 and Rybka 1.0 Beta 1.0 decompiled source code by Ed Schröder
  75. ^ Anthony Cozzie speak ! by Silvian, Rybka Forum, February 03, 2008
  76. ^ ChessBase: A Gross Miscarriage of Justice in Computer Chess by kingliveson, OpenChess Forum, January 02, 2012
  77. ^ Re: ChessBase: A Gross Miscarriage of Justice in Computer Chess by BB+, OpenChess Forum, January 02, 2012
  78. ^ Re: Hyatt Is Gone! by BB+ OpenChess Forum, Jan 03, 2012
  79. ^ Rybka evidence recapitulation by BB+, OpenChess Forum, January 03, 2012
  80. ^ Søren Riis (2012). A Gross Miscarriage of Justice in Computer Chess. pdf hosted by ChessBase

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