Reports | June 29, 2011 8:42

Rybka disqualified and banned from World Computer Chess Championships

Rybka disqualified and banned from World Computer Chess ChampionshipsThe International Computer Games Association (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.

For quite a while there has been some serious turmoil in the computer chess world. When we reported about the Houdini-Rybka match in February of this year, the article triggered lots of comments about the issue of cloning. Was Houdini derived from the Ippolit series? Was it plagiarized from Rybka? And what about Rybka, was it largely based on the code of other engines? Nine days later we published an article by IM David Levy, President of the International Computer Games Association (ICGA), who shared his thoughts about how to tackle the issue. A few days later he announced the establishment of the ICGA Clone and Derivative Investigation Panel. Not long after, on March 1st, we received an open letter about the Rybka-Fruit case signed by fourteen chess programmers. They all supported the claim that Rybka was cloned from Fabien Letouzey’s Fruit. In the last few months all the allegations have been seriously studied by the International Computer Games Association (ICGA). On Tuesday night we received the following text from the ICGA President himself.

Rybka Disqualified and Banned from World Computer Chess Championships The International Computer Games Association (ICGA) has been conducting an investigation into allegations that, in the chess program Rybka, the programmer Vasik Rajlich plagiarized two other programs: Crafty and Fruit. The ICGA has considered and evaluated the evidence presented to the investigation panel and the report prepared by the panel’s Secretariat. (The report and evidence files are attached.) We would like to thank those members of the panel who contributed to this investigation and the Secretariat for the enormous amount of conscientious work they have put in to this matter. By a unanimous 5-0 decision of executive members of the ICGA we find ourselves in agreement with the verdict of the Secretariat’s report. We are convinced that the evidence against Vasik Rajlich is both overwhelming in its volume and beyond reasonable question in its nature. Vasik Rajlich is guilty of plagiarizing the programs Crafty and Fruit, and has violated the ICGA’s tournament rules with respect to the World Computer Chess Championships in the years 2006, 2007, 2008, 2009 and 2010. Specifically, Vasik Rajlich, on all five occasions, violated Tournament Rule 2 which requires that: Each program must be the original work of the entering developers. Programming teams whose code is derived from or including game-playing code written by others must name all other authors, or the source of such code, in their submission details. Programs which are discovered to be close derivatives of others (e.g., by playing nearly all moves the same), may be declared invalid by the Tournament Director after seeking expert advice. For this purpose a listing of all game-related code running on the system must be available on demand to the Tournament Director. By claiming other programmers’ work as his own, and failing to comply with the abovementioned rule, Vasik Rajlich has unfairly been awarded one shared 2nd-3rd place (in 2006) and four World Computer Chess Championship titles (in 2007, 2008, 2009 and 2010). Furthermore, it seems to the ICGA that Vasik Rajlich clearly knew that he was in the wrong in doing so, since he has repeatedly denied plagiarizing the work of other programmers. The ICGA regards Vasik Rajlich’s violation of the abovementioned rule as the most serious offence that a chess programmer and ICGA member can commit with respect to his peers and to the ICGA. During the course of the investigation and upon presentation of the Secretariat’s report Vasik Rajlich did not offer, despite repeated invitations from the ICGA to do so, any kind of defence to the allegations, or to the evidence, or to the Secretariat’s report, other than to claim in an e-mail to myself on May 13th 2011 that: Rybka has does not "include game-playing code written by others", aside from standard exceptions which wouldn't count as 'game-playing'. The vague phrase "derived from game-playing code written by others" also does not in my view apply to Rybka. The ICGA is of the view that such a serious offence deserves to be met with correspondingly serious sanctions against the perpetrator. In deciding on appropriate sanctions the ICGA has borne in mind the approach of the International Olympic Committee for dealing with the most serious cases of the violations of its rules. The ICGA has therefore decided as follows:

  1. Vasik Rajlich is hereby disqualified from the World Computer Chess Championships (WCCC) of 2006, 2007, 2008, 2009 and 2010.
  2. The 2nd-3rd place awarded to the program called “Rajlich” in the 2006 WCCC is hereby annulled, sole 2nd place is awarded to the program Shredder, and 3rd place in that event is awarded to the program Zappa.
  3. The 1st places and World Computer Chess Champion titles awarded to the program Rybka in the 2007, 2008, 2009 and 2010 WCCCs are hereby annulled, and all the other programs that competed in those events are moved up in the final tournament standings by one place. Thus the revised tournament standings and titles for those events will now be as follows. 2007 1st Zappa (World Champion) 2nd Loop =3rd GridChess =3rd Shredder 2008 1st Hiarcs (World Champion) 2nd Junior 3rd Cluster Toga 2009 =1st Junior (Joint World Champion) =1st Shredder (Joint World Champion) =1st Deep Sjeng (Joint World Champion) 2010 =1st Rondo (Joint World Champion) =1st Thinker (Joint World Champion) 3rd Shredder
  4. In due course those programmers whose programs have been elevated to World Champion (or joint World Champion) status will receive from the ICGA replicas of the Shannon trophy for the appropriate years.
  5. The plaques on the Shannon trophy that currently bear the name Rybka (for the years 2007-2010) will be removed from the trophy and new plaques will be engraved with the names of the revised winners of the title.
  6. Similarly, the titles of World Computer Speed (Blitz) Chess Champion that were awarded to Rybka in 2009 and 2010 are hereby annulled. The revised winners of the speed chess title for those years are therefore: 2009 Shredder 2010 Jonny and Shredder (joint champions)
  7. Vasik Rajlich is banned for life from competing in the World Computer Chess Championship or any other event organized by or sanctioned by the ICGA.
  8. The ICGA demands that Vasik Rajlich return to the ICGA the four replicas of the Shannon Trophy presented at the World Computer Chess Championships in 2007, 2008, 2009 and 2010, and to return to the ICGA all prize money awarded for Rybka’s performances in those events.

David Levy [President - ICGA] June 28th 2011

Mr Levy also sent us a big number of documents which according to the ICGA form the evidence to the claim that Rybka was plagiarized from Crafty and Fruit. These documents can be downloaded below for anyone who wishes to dive further into the material. The news is obviously a huge blow for the Rybka team. The impact in the computer chess world must be comparable to arguably the most famous example of doping in athletics: the positive drug testing of Canadian sprinter Ben Johnson in 1988. We've asked Vasik Rajlich for a comment and hope to add this later.


Peter Doggers's picture
Author: Peter Doggers

Founder and editor-in-chief of, Peter is responsible for most of the chess news and tournament reports. Often visiting top events, he also provides photos and videos for the site. He's a 1.e4 player himself, likes Thai food and the Stones.


MarkWatkins's picture

I will try to rebut each of your points, to the extent that I understand them.

Your 64%-96% analogy is misguided, and is based upon a wrong statistical measure. Take the following experiment: I give you samples of chimpanzee and human DNA, not saying which is which. Given good enough samples, any decent lab in can determine which-is-which with a probability of something like 1 in 10^10 (I don't know the exact number). That probability is the relevant one, not the "96%".

Similarly, in the statistical analysis of "evaluation feature overlap", it is not "64%" that is relevant, but the statistical chance of this event in the relative sampling set. Comparing the raw numbers of 64% in evaluation features to 96% in DNA is pointless, and you might as well just argue something like "64% is more than a 50% coinflip, so it's unlikely to come from chance." After a proper sense of numeracy is introduced, your argument vanishes.

Regarding the source code: it is not technically needed (though its absence made the investigation more time-consuming), and indeed any FSF action or court case will likely proceed against Rybka even without it. As regards to whether this is "circumstantial", I might remind you that copyright law (which is an imperfect surrogate here) is almost of necessity based upon "substantial similarity" (see e.g. Nimmer on Copyright), and this was largely the standard the ICGA investigation used. [The fact that illegal copying is typically not a criminal matter greatly relaxes the standard of proof -- or rather, the fact that direct copying is so difficult to show in most cases means that it is relegated to a civil matter, where strong indirect evidence typically suffices].

Also, there were multiple outside "auditors" who would likely have been willing to inspect it (had Rajlich offered), such as Ken Thompson (inventor of the C language) and Jonathan Schaeffer (solver of checkers), or an ICGA rep like Yngvi Bjornsson or Remi Coulom. Again this seems almost a petty strawman argument to me.

The reason this took 5 years is multi-faceted: first, the initial effort to disassemble and investigate the code is already a year or more (it might be 3 months for someone working fulltime). Secondly, Fabien Letouzey left the chess world, and a misinterpreted email from him on a related subject in 2008 (about Strelka) left many to think he really didn't care. Only when he got involved was there any widespread desire to investigate (e.g. Mark Uniacke first looked at evidence once Fabien was involved in Feb of this year). I don't think 5 years is an abnormal timeframe in the software world in any event, especially when you consider that Rajlich took pains to obfuscate some of Rybka's internals.

Finally, I do not know how you calculate that a "huge majority" of Panel members are Rajlich's competitors. Most of the chess programmers on the Panel *never* competed against Rajlich in an ICGA event, the exceptions being (by my calculation): Ban, Czechowski, Letouzey, Isenberg, Horvath, Himstedt, Uniacke, David, Schaefer, Pijl, Meyer-Kahlen, and Wegner. You might count Bauer, Hallsworth, and Williamson also. So of the 35-40 Panel and Board members, only about 15 were his competitors in ICGA events at one time or another, and perhaps a few others (Hyatt, Dailey) competed against him in a non-ICGA event.

Imran's picture

Excellently said.

Johnny's picture

You cite 64% overlap in support of the contention that the evaluation function is "nearly identical", since others "averaged" about 40%. Please explain how a "proper sense of numeracy" renders 64% as "nearly identical". My personal sense of numeracy suggests that the conclusion, "nearly identical", connotes 95% or higher.

Anyway , your patronizing reference to copyright law is not only an "imperfect surrogate" (LOL!) but is rather completely absurd and nonsensical. An engine algorithm or code is a process designed to accomplish a particular function, namely the evaluation of a chess position. A more proper analog is patent law (which covers functional processes rather than aesthetic expression like literature/music), not copyright law. I am a real estate lawyer (not intellectual property) but i believe the standard for patent infringement is "substantially equivalent" rather than "substantially similar." Obviously "equivalent" is a higher standard than "similar." So please try your argument again, without the condescension this time.

Finally, your point that most panel members' engines did not compete in ICGA events is utterly irrelevant. Obviously, *any* engine author is a Rybka competitor in the consumer market of chess engines, regardless of participation in self-important ICGA events. Indeed the consumer market competition ($) is the only one that matters. Seems to me having rival engine authors act as factfinders here is analogous to Linux Torvalds and the CEOs of Apple, Google, Sun/Java, Netscape, acting as jurors in a trial of Microsoft concerning events from six years ago. And why on earth is it incumbent on Rajlich to suggest a neutral auditor, as you say?? Isn't it ICGA's obligation to have neutral factfinders in the first instance?

To me, it seems the bottom line is that ICGA is a private organization and can be safely ignored. There is not, for example, a court issued injunction preventing Rybka from selling its product. As for a civil suit, if i were a betting man i would say Rybka's chances in a lawsuit for defamation and libel are at least equal to any claims that Rybka violated the GPL license. Moreover, being a commercial enterprise, Rybka could easily point to damages, whereas Fruit and Crafty-- both freeware-- could not.

For the record, I personally prefer Stockfish anyway and so could care less of Rybka's fate, or that of the ICGA for that matter.

TMM's picture

Very well said Johnny.

And I'm curious how Rybka and ChessBase will respond to this, also since there is no mention of this news on the ChessBase website yet. Indeed it seems that the ICGA is a private organization which can do whatever it wants, so even if the Rybka team has convincing arguments why they should not have been "convicted", the ICGA may simply ignore them. So maybe Rybka and/or ChessBase will go to court instead.

Bert de Bruut's picture


"My personal sense of numeracy suggests that the conclusion, “nearly identical”, connotes 95% or higher." The issue with attorneys (and sollicitors and judges) is that they usually have cut back on math (as well as on other science) from the third or fourth year of high school. So a technical discussion between experts that very few people can follow to begin with, certainly cannot be understood by the vast majority of lawyers.

"A more proper analog is patent law (which covers functional processes rather than aesthetic expression like literature/music), not copyright law." The GPL license that Fruit was under is a copyright license, and the issue here is called plagiarism for a reason. Besides, anything written, like software, is hard to get patented, especially so in Europe. This was different in the 17th and 18th centuries, when books could be patented as well, but nowadays texts can only be copyrighted.

"Isn’t it ICGA’s obligation to have neutral factfinders in the first instance?" ICGA itself is not having a commercial interest in the matter, so the organisation (not necessarily its members) could be considered impartial in the affair. On the other hand, now that his reputation is on the line, Rajlich would be wise to get some impartial experts assert his lovechild is not what ICGA claims it to be. Fortunately the Rybka team is able to pay the bills that come with this advise, thanks also to winning the ICGA championships so frequentely.

"ICGA is a private organization and can be safely ignored". Sure it is, but then ICGA is around since the microprocessor stone age, so it bears some relevance to the computer chess scene.

"If i were a betting man i would say Rybka’s chances in a lawsuit for defamation and libel are at least equal to any claims that Rybka violated the GPL license." And my bet would be that due to the excessively difficult tecnical issues involved, a lawsuit would dragg on for many years, without the court ever reaching a verdict.

"For the record, I personally prefer Stockfish anyway" Here I heartily agree with you: SF 2.1 kicks ass!

Rune's picture

64% of behaviour is not the same as 64% of the code. Does 96% of shared DNA mean that 96% of human behaviour is chimpanzee? Well, it probably is. Bad example. But a small change in DNA or source code can make a big change in behaviour.

Your view of programming is simplistic. Programming is a lot like writing. There is a lot of ways to express an idea. Two programmers will not create identical code, and two writers will not write identical articles, even if they have similar views on the subject.

MarkWatkins's picture

Quoting Johnny: You cite 64% overlap in support of the contention that the evaluation function is “nearly identical”, since others “averaged” about 40%. Please explain how a “proper sense of numeracy” renders 64% as “nearly identical”. My personal sense of numeracy suggests that the conclusion, “nearly identical”, connotes 95% or higher.

Again I use the coin flip analogy. I flip a coin 1000 times. It comes up heads 64% of the time. Would you say the coin is fair because it didn't reach a "95%" limit? No, for this is the wrong metric. In fact, this "95%" barrier is simply saying a 1 in 20 chance. The chance of getting 640 or more heads from 1000 flips is nearly 1 in 10^20. The Fruit/Rybka analysis put the chance of their "64% overlap" being accidental at something like 1 in 10^8 [the exact number is open to dispute of course, but there was no rebuttal]. This is the important number, which could be construed as 99.99% certainty if you like.

Regarding patent versus copyright law, I'm not sure what you are saying. Certainly the operative umbrella for any FSF/SFLC action will be copyright law. If the dispute is to which system (patent/copyright) the ICGA should take as a (vague) model for its considerations, a traditional argument is that the WCCC is more of a *programming competition* than anything else (viz. the *author* is considered an inseparable part of the entry). If the competition were solely about choosing the best chess moves in a given timeframe, using whatever hardware/software you could obtain (something like Freestyle Chess), then I would be more apt to agree that functionality (and ergo something akin to patent law) was the primary consideration.

In your next paragraph, I don't see how having competitors act as fact-finders is anything like competitors acting as jurors, but then maybe I don't understand law too well. :) Furthermore, given that facts are, well, *facts* (and ample opportunity to dispute their factuality and/or relevance was given), it would seem not to matter whether those who found them were "neutral". I agree that the *interpretation* of facts is more dicey, but as stated multiple times, Rajlich simply chose not to offer any alternative interpretation. I don't think I ever proposed that Rajlich name a neutral auditor, but simply suggested that there were many outsiders available (and he could even have the choice of which one, if he liked) if source code and privacy therein had turned out to be an actual issue.

As for the GPL and any legal action, my own opinion is that the locality could make a large difference, and Poland (for historical reasons) has rather stringent copyright laws. At the risk of being condescending, I'll point out that most trials in Poland are bench trials, there are no general standards of proof but rather the judge on his own authority decides such for the particular case, punitive (triple) damages can apply in copyright cases, and a successful plaintiff can even demand a separate contribution to a "Creative Fund" -- see Chapter 9, Article 79 of

Johnny's picture

First, derivative does not mean "nearly identical". Your argument goes to showing derivation, not showing "sameness" in the end result. Output that is derived may not be identical nor even "nearly identical" to the source.

Second, the GNU Public License is limited and restricted by its own terms to elements that are copyrightable. Please read it carefully: “The Program” refers to any copyrightable work..." To "propagate" a work means to commit an "infringement *under applicable copyright law*". In the USA, the extent of copyright protection on software code is determined on a case-by-case basis by application of the so-called "Abstraction Filtration Comparison Test".

Elements dictated by efficiency, elements based on standard programming techniques, and elements taken from the public domain are excluded from copyright protection and therefore not even within the scope of the GPL.

Accordingly, under the terms of the GPL, a programmer may *copy* or plagiarize from portions of source code, to the extent that such elements are not subject to copyright protection in the first instance and/or no "copyright infringement" has been committed. Let me spell this out for you: if Rajlich copied elements that are excepted from copyright protection, he did not violate the GPL. Copying does not necessarily amount to a copyright infringement. For instance, every engine author's opening book is "copied" from somewhere. Did you invent the Ruy Lopez?? However, opening moves are not subject to copyright protection and thus the GPL does not and cannot apply to Ruy Lopez theory. Many elements of software code are also simply beyond copyright law and not even covered by GPL. The Panel did a sloppy rush job without bothering to interpret these outcome-determinative issues. Again, this is all unbelievable since the events in question occurred in 2005-2006.

Of course it matters who the decisionmaker is. Fairness and justice require an impartial decisionmaker. That discussion is not worth addressing.

Johnny's picture

Two points i left out:

(1) The panel's misapplication of the phrase "nearly identical" to mean "derivative" is fatal, since the former amounts to "copying/plagiarism" and the second does not. Not to mention that this distinction would matter in a lawsuit for libel and defamation.

(2) The GPL's incorporation of "applicable copyright law" also means that any and all defenses within copyright law (fair use comes to mind) are available to Rajlich. Fair use permits use of copyrighted material if used sparingly and/or where there is transformative value, among many many other factors (none of which factors the panel bothered to consider).

You can ridicule lawyers all you want, but as a group we tend to be precise with our words.

MarkWatkins's picture

1. The Panel and the Board were only interested in whether Rajlich violated ICGA Rules, not about copyright law or the GPL *per se* (if they had been, lawyers would indeed have been necessitated!). Various parts of copyright law were taken as a framework for discussions about what "originality" meant, but copyright law certainly was not seen as definitively normative by any means. E.g., Rajlich was not found guilty because the Board thought he broke the GPL, but because he broke the ICGA Rules. Maybe I've lost the thread of this discussion, but I'm not sure where the Panel substituted "derivative" (in the GPL sense?) to mean "nearly identical". You and I may just be talking past each other, as I view the ICGA process and any GPL action as distinct, though with many mutual elements.

The Board verdict seems to agree that (in particular) the congruence between Rybka and Fruit evaluation features was significantly more than any reasonable interpretation of the rule "Each program must be the original work of the entering developers" would allow. The same rule also says: "Programs which are discovered to be close derivatives of others [...] may be declared invalid". The Report used the phrase "nearly identical" to indicate the unlikelihood of the Rybka/Fruit happening by chance (approximately 1 in 10^6, or more), thus contra-indicating the word "original" in the ICGA Rules.

2. The question (again in the ICGA context of "originality") of whether parts of Rybka could be considered "fair use" (such as implementing the UCI protocol, or rotated bitboards, or whether only non-protectable items such as "ideas" were copied) did come up in Panel discussions. The Panel report concluded (in essence, and among other things) that: a) specific sets of evaluation features were "protected expression" [again in analogy to copyright law, but not using it *per se*], b) the amount of "protected expression" of Fruit that appeared in Rybka was substantial, much beyond *de minimis* [I suspect that the Panel would agree that there was some transformative value, but that it was not sufficiently dominant so as to exclude the initial holder's rights]. It is hard to interpret Rajlich's brief sentences, but he seemed to think otherwise, though offering no real reason why. The Board appears to have agreed with the Panel Report.

Switching back to the GPL/copyright situation, it is my opinion [after a forum discussion a few months back with a lawyer named John Manis, and my interpretation of the Romeo and Juliet example in *Nimmer on Copyright*] that the particular expression of choice of evaluation features in a chess program is "protected" by the applicable law (Polish in this case), though I fully expect others may disagree. I cannot speak for other Panel members, but I was certainly aware of the specific issue you raise, namely that the GPL is a *license* (not a contract) and as such can extend beyond what copyright law already provides. However, in any event, as indicated above, any legal notion of copyright was beyond the scope of what the Panel and Board addressed vis-a-vis the narrow question of whether Rajlich broke the ICGA Rules. [As noted above, the Panel did occasionally indulge in quasi-legal ruminations for "fair use" analogies].

3. You can ridicule the internal quasi-legal machinations of a private organisation all you want, but as a group they tend to know best how to handle their own affairs. This particular process was not perfect, but could hardly be considered to be shambolic. [Your point that the Panel report should perhaps have steered clear about mixing the GPL/copyright issues with ICGA issues is well-taken -- but you might note that it phrased in the if-then form: "If there was a GPL violation, then Rybka *also* broke the ICGA Rules", with no implication contrariwise]. If you want a precedent for disqualification in similar circumstances:

Incidentally, the tournament director Jaap van den Herik has a speciality in some aspects of cyberlaw (though not intellectual property particularly).

adam's picture

God had nothing to do with that. However, one can easily claim that Rykba evolved from Fruit/Crafty via natural selection. :D

cata's picture

What do you mean, he gave credit? The quote right there from him asserts his claim that he did not use any code from other engines. That is the opposite of giving credit.

Tragisk's picture

He gave credit to Fruit etc., he said he took a lot of ideas. Houdart also denied copying code.

Bobby's picture

The stories behind Rybka and Houdini are very similar. Both authors admitted using lots of ideas, which is quite normal for software development in general, and in the CCC community. They also denied copying code, except Vas admitted copying some general public domain code snippets. Both authors probably copied more than that, but that is also quite normal for software development. You can say that ICGA probably reacted a bit over the top. What about the other engines? I guess we can safely conclude that Crafty and Stockfish are clean, but there are lots of other engines to worry about.

harami's picture

I feel bad for Topalov's team. Even the software they used involved cheating ..

, and now Danailov will accuse Rajlich of Cheating too ?... LOL
( sorry could not resist )

mike's picture

Also, 2012 BMW is a clone of 1925 Ford !!

Sergio's picture

There is probably even an higher overlapse then 64%,since both cars got 4 wheels, a steeringwheel and an engine.

Zeblakob's picture

There are rumours stating that Houdini iz a also a clone.

DaveJames's picture

@freakclub Matthew and Luke and Mark were each direct and at times indirect witnesses to the event of Jesus' life on Earth, however qualified to relate what was common knowledge or accurately relayed to them about Jesus, much more so in Marks case. The CANDOR of these three Gospels accountings are proof that they are individual works. In addition we see that "...all scripture is inspired of God". These books, under the microscope, suffer no such accusation.

Oh Rybka Rybka Rybka!!! Yes, all would be well if the help from other engines was admitted at the start.

How original and magnificent was/is Fruit now? Well for now it stands as very original and very magnificent and very innovative.

Michael Lubin's picture

Your faith-based ignorance concerning the Bible shows. Read any reputable New Testament scholar and they will tell you that yes, much of Matthew and Luke were copied from Mark. Off-topic, I know.

Dave Acevedo's picture

How about just reading the books themselves? There is no "copying". If you and I watch a chess match are we to be accused of copying if we both include the move list and commentary however with different observations and energy levels? No one would say that is copying. And no one has to any great success. All four prophets while addressing many of the same subjects - very often make very different descriptive points.

Michael Lubin's picture

Of course they make different points. They were four different writers. It's just that two of them relied heavily on a third for a lot of their material, much of which is reproduced VERBATIM--not something that would happen by coincidence, just as with Rybka's copying. It should be pointed out that in the first century, nobody saw anything wrong with copying someone else's book. It was a normal practice. Much of the books of Chronicles in the Old Testament were copied from Samuel and Kings, is another example.

noyb's picture

Levy and his cronies should be ashamed of themselves. They tried and convicted Raj with trumpted up "evidence" without even giving him a chance to defend himself. Who do these guys think they are, Soviet Communists?! Perhaps it's time to expose the ICGA!

tg's picture

I am pretty sure that asked Vas for comments and a defense.

Johnny's picture

Based on the American legal system as a reference point, basic fairness and justice would require notice of the charges, notice of the possible penalty, an impartial magistrate, and an opportunity to defend oneself.

I don't know whether the notice was sufficient, but I doubt it. The decisionmakers (Vas's competitors) cannot be considered entirely impartial. And did Vas have an opportunity to review and respond to the reports before they were publicized? Again, I doubt it.

TG's picture

Vas was given notice, and asked submit a defense. He didn't.

Harvey Williamson's picture

At least half of the panel members have never competed against Rybka at the WCCC or a similar event.

MarkWatkins's picture

Quoting Johnny: "Based on the American legal system as a reference point, basic fairness and justice would require notice of the charges, notice of the possible penalty, an impartial magistrate, and an opportunity to defend oneself.

I don’t know whether the notice was sufficient, but I doubt it. The decisionmakers (Vas’s competitors) cannot be considered entirely impartial. And did Vas have an opportunity to review and respond to the reports before they were publicized? Again, I doubt it."

Notice concerning the opening of the ICGA proceedings (and an invitation to join the Panel) was given to Rajlich in early March. Notice regarding the progression of the Panel was given on April 4th, with a request that if he wanted to comment on the evidence, he should do so before May 4th (if he chose to make no comments, the investigation would close April 18th). Notice of the conclusion of the investigation stage, complete with (access to) the entirety of the evidence and a copy of the Panel report was given to Rajlich on May 13th, with a request to make any comments within a month. A reminder was sent to him 2 weeks later.

Notice of the possible penalty was (I think) mentioned in the first communication to Rajlich in late February or early March, and it was definitely part of the founding Charter of the Panel. The Panel was reminded (more than once) to keep various things private until Rajlich had been given a chance to respond.

The decision makers were the ICGA Board, none of whom has ever competed against him. Rajlich was (more than once) offered the opportunity to defend himself, and chose to do little more than write the 2 lines Levy excerpted above.

In short, the process seems to have included all of:
*) Notice of charges
*) Notice of possible penalties
*) Impartial magistrate
*) Opportunity to defend oneself

I think you greatly underestimate the trouble that David Levy (in particular) went to, so as to ensure fair proceedings.

Johnny's picture

And who appointed David Levy as judge, jury, and autocrat in charge of the ICGA?? Oh that's right, David Levy.

MarkWatkins's picture

"The ICGA was founded as the ICCA in 1977 by computer chess programmers to organize championship events for computer programs and to facilitate the sharing of technical knowledge via the ICCA Journal." It has rules (or by-laws) for such things as membership and competition as might be found in any other private organisation. A competitor in their tournaments should have a reasonable expectation to abide by these.

David Levy was (re-)elected President in 2008, and under Section 2 Article V presides over the Council (which is the governing body of the ICGA) in this capacity. As stated in the Constitution, such elections are triennial, and require a quorum of at least 20 persons.

If you care to read the ICGA Constitution (probably not worth it I admit):

Harvey Williamson's picture

If you read the evidence you will see that Vas was asked to supply evidence. He decided not to defend himself.

Galaad's picture


Can't you read an article? Rajlich was given numerous occasions to defend himself, and he constantly ignored them. Which in itself is a confession.

Luxusohr's picture

I wonder if i now can give back my Rybka World Computer Chess Champion products to chessbase ?

MarkWatkins's picture

If you bought the products solely, or at least primarily, due the label of "World Computer Chess Champion", you might have a claim. Even so, I feel it is at best tendentious, as Rybka truly owned the WCCC title at the time of the sale, so it is not really (say) false advertising. Whether any legal action would be against ChessBase or Rajlich directly is also an issue (though in any event, I'd suspect their contract with him would provide indemnification).

Mauricio Valdés's picture

So, has Rybka become the Topalov/Danailov of the computers?
Toiletgate II The revenge of the machines!

Zeblakob's picture

hehehe, very funny ...
btw I avoid eating and reading comments at the same time

blackhorse's picture

"Rybka investigation report" link does not work.

Stephen Alzis's picture

Here is the exact link:

You guys at chessvibes, check from time to time your links.

Otherwise, excellent stuff!

Peter Doggers's picture

Thx, corrected. It was late last night...

Enrico L. Carrisco's picture

It sure took a lot longer than it should have. I and many others (Anthony Cozzie, Dr. Hyatt) provided a lot of evidence when Rybka (1.0) beta hit the scene back in 2004.

Here's a short synopsis copied from CCC archives:

Finally, partial justice has been served. I'm glad Fabien finally became involved as that was the missing ingredient.



jhoravi's picture

The problem with the judging panel is that they are all programmers who are jealous about Rybka.

silvakov's picture

Probably half the computers which competed in these World Championships had, in some way, older counterparts' code. It's difficult to imagine every single one of these programmers creating a whole distinct code from scratch, "inventing the wheel" multiple times, all in their own way...

Arne Moll's picture

As quoted in my article on the Firebird-Rybka controversy from some time ago, Rajlich has commented on the influences of Rybka in the past, albeit rather evasively:

Hernandez: What chess engines in public domain, when you got started, had the biggest influence on the earliest versions of Rybka?

Rajlich: Well, actually I started in a kind of strange way. I printed out just about every single paper there was to print out about computer chess; all these academic papers. A lot of them are interesting, a lot of them are just really relevant, actually. (…) So I kind of started to work through that, that was how I started. Probably it’s not the most efficient way to do it. Probably the most efficient way is to take an open source program – at that point it would have been Crafty – and just kind of go through that. And I gradually worked around through that. (…)

MarkWatkins's picture

It might be wise to remember that "taking what's out there" is perfectly legit in some computer programming circles, and that Rajlich probably developed his ethical sense according to what he saw done when he was employed in industry. Over time, the incongruence between his ethical concepts and those of the majority in the (rather tightly-knit) computer chess world mushroomed into a serious problem. Furthermore, he temporally emerged right when the whole question of "open-source" was becoming somewhat of a bugaboo, with various opinions about whether it helped or hurt computer chess, and in what sense.

Given that the final Panel consideration was essentially unanimous [that is, no one voiced disapproval], with amateur programmers, commercial (both chess and otherwise) programmers, and academics alike in agreement, I can't say he got too hard of the bargain regarding any pedantry about what "plagiarism" means.

Antonius's picture

Those guys will be destroyed by Ribka team's advocates in normal court...

Zeblakob's picture

Thy have to choose advocates who understand nothing in cumputer science, otherwise an advocate with little knowlege in computer science would never accept to defend them

TMM's picture

That depends a bit on what the ICGA is. For example I could start a new private organization for myself (e.g. the QWE), and ban you from this organization. Could you sue me successfully then? Or if I gave you the title "QWE World Champion", and then disqualify you, could you sue me then?

The trophies and the money however is a different issue. I don't see a court order forcing Rybka's team to give back prize money or trophies, and I don't think a private organization has authority to force this. In that case I agree that Rybka's team could destroy the ICGA in court.

zohan's picture

lets see if Rajlich is as slippery as Rybka in court>

Imran's picture

Forget about Rybka.We already have Houdini and now have the new Critter 1.2 which is crushing Rybka 4.
This business is over.

Zeblabob's picture

Thats funny: meta-cheating, some GMs cheats using a cheater engine.
BTW, from the beginning I hate Rybka and I do not know why.


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