/ Rob Beschizza / 11 am Thu, Jan 19 2012
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  • Plagiarism claims roil chess coding scene

    Plagiarism claims roil chess coding scene

    The hardest-fought battles in modern chess are between computers, but angry fights over who authored these cutting-edge number crunchers come a close second. Rob Beschizza reports on a disgraced chess AI champion's last stand

    Rybka, a powerful chess program, was stripped last year of its titles and its author publicly disgraced. Declared a plagiarist by the International Computer Games Association, Vasik Rajlich was also handed a lifetime ban on competition and ordered to return thousands of dollars in prize money. But the investigation's conclusions are now being challenged, opening a fissure in the computer chess community.

    Debate centers on chess-playing algorithms found both in certain versions of Rybka and another program, Fruit. Both programs emerged in the mid-2000s, outpacing established competitors in short order. But while Fruit appeared first, it was Rybka that came out on top, claiming world championships from 2007-2011 and forging a path to commercial success.

    The rancor shows how traditional ideas of plagiarism blur when a development community is built around a set of technical problems so specific it's nigh-impossible to avoid following the leader—and where a limited market makes open source a dangerous place to put cutting-edge ideas.

    Backed by a technical report in which Rybka's binary code was disassembled to reveal its inner workings, the ICGA found in June 2011 that Rajlich infringed others' copyright and failed to disclose the origins of his software on competition entry forms.

    "Not a single panel member believed him innocent," the report stated. "Vasik Rajlich’s claims of complete originality are contrary to the facts."

    The ICGA, founded in 1977, organizes international computer chess tournaments and publishes a trade journal. Since last year's findings by its 34-member panel, however, furious exchanges between Rajlich's critics and supporters have turned some of chess programming's popular forums into war-zones. The imbroglio culminated last week in a 31-page rebuttal published by Chessbase, which sells Rybka at its online store.

    "The ICGA’s findings were misleading and its ruling lacked any sense of proportion," wrote its author, Dr. Søren Riis, a computer scientist at Queen Mary, University of London. " ... It is clear that Rybka is an original program by any reasonable standard."

    In his report, published in four parts, Riis argues that the investigation exaggerated the infraction's significance and was informed by fabricated "recreations" of Rybka code presented as the real thing. Riis also suggested that the ICGA's actions served some panelists' commercial interests.

    "Rybka competitors, individuals with obvious conflicts of interest, and individuals who had publicly expressed their predetermined conclusion of guilt were allowed to join the investigation." Riis wrote "... This attitude, I think, is a classic example of losing the plot."

    Within days, ICGA president Dr. David Levy issued a fresh rebuttal, insist that Riis' objections missed the mark.

    "[Riis] does nothing in my view to make the case for a miscarriage of justice to have taken place," Levy wrote. "It is, put simply, biased reporting."

    The issue is muddied by the highly specific nature of the chess-playing code at hand, which seems to hover at the point where ideas and algorithms meet the copyright-protected expression of computer software. For his part, Rajlich continued to insisting that his work on the latter was entirely original, while saying that he had never denied using Fruit's ideas in his work.

    "This document is horribly bogus," Rajlich said of the original report. "All that 'Rybka code' [in it] isn't Rybka code, it's just someone's imagination."

    If its critics are right, the ICGA hung Rajlich on a vague technicality to serve the interests of his commercial rivals, even though many of them may have likely benefited from similar practices.

    "I don't think Dr. Levy was in an easy situation," Riis said. "His organization would vanish without chess programmers, and most of the active chess programmers in his organization wanted him to take action against Rybka."

    If the ICGA is right, however, the most powerful program in the game is built on a fraud, by a man who misled his peers and parlayed others' open-source work into a proprietary and profitable empire.

    "How would we view an Olympic athlete found guilty of taking performance enhancing drugs if he performed superbly, winning races by huge margins, breaking world records and taking gold medals?" writes Levy, in his most recent missive. "Would he be forgiven his drug taking just because his performances were outstanding? No, of course not!"

    Dr. Levy said he would be unavailable for further comment this week, but planned to do so soon.


    Chess is a simple game of marvelous depth. Though it uses a small set of deterministic rules and is played out on a board of just 8x8 squares, even the most powerful computers cannot see far into the maze of possibilities that fan out from a complex position.

    As a result, computers cannot use brute tactical force to defeat a human master's capacity for long-term strategy and pattern recognition. Instead, heuristics are required, in the form of code used to explore possibilities, recognize powerful piece formations, and so on. Chess programs are exquisitely tuned to discard unlikely lines and to ignore material values in favor of gambits and subtle plans.

    It's one such heuristic in Fruit—its algorithm for evaluating the strength of a chess position—that early versions of Rybka allegedly stole.

    Fruit, created by Fabien Letouzey, emerged in 2004, and was initially an open-source project, its code clearly visible for others to read. It placed second in the 13th World Computer Chess Championship in Reykjavik in 2005—a striking result that put it in contention with top-flight commercial engines such as Fritz, Shredder and Junior.

    Enter Rajlich, a U.S. and Czech citizen born in 1971 in Cleveland, Ohio. Though he attained International Master status, Rajlich realized that he would never reach the game's top echelons. Determining instead to be the world's best chess programmer, he set out in 2003 to create an engine able to compete with the greatest.

    An early version performed poorly, finishing near the bottom in a crowded 2004 tournament. But at the 5th International Paderborn Computer Chess Championship, in December 2005—a few months after Fruit's winning debut—the strength of Rajlich's program increased dramatically. Within a year or so, Rybka was the strongest chess machine in the world.

    "Rybka did not merely win nearly every tournament it entered," Riis wrote. "It won them with a near-90% success rate. It is difficult to overstate the degree of superiority that the Rybka team exhibited..."

    It took a while for others to accept the new normal. In 2007, according to the New York Times, a clash between Deep Junior and Deep Fritz was billed as "The Ultimate Computer Challenge", even though by then Rybka was clearly superior to both.

    And there were suspicions almost from the beginning, stoked by the evident similarities between Fruit and Rybka and the fact that the latter was a closed-source product, its code unavailable for inspection.

    Rajlich, who now lives in Warsaw, Poland, always insisted that his work does not include "game-playing code" written by others: “Rybka is and always was completely original code, with the exception of various low-level snippets which are in the public domain," he said in 2007, responding to early rumors.

    It stayed on top until the appearance of Robart Houdart's Houdini, which defeated Rybka in a series of 40 games in February 2011. The match-up led to renewed scrutiny of both programs, as Houdini itself was apparently derived from Ippolit, an engine claimed to be derived from Rybka. The claimant? Vasik Rajlich himself.

    If all this sounds to you like quite a tangle, you're not alone. On Feb. 19, 2011, Levy published an article titled "Attack of the Clones", in which he complained about the growing trend of ripped-off chess engines. Of those identified, however, "The Rybka-Fruit Case" took center stage. Levy cited Rajlich's as an example of a "sophisticated cloning effort" in which efforts were made to "obscure the original source of the algorithms." Shortly thereafeter, Letouzey and 15 other chess programmers published an open letter asserting likewise.

    "By using and deriving code, data and structure from Fruit 2.1, Vasik Rajlich was able to make dramatic and huge progress with 'his' program Rybka to the detriment of his fellow competitors," wrote the accusers. "In our view this has made competitions involving Rybka grossly unfair. As chess programmers we find this overwhelming evidence compelling. We believe Rybka is a Fruit derivative albeit an advanced one."

    The ICGA investigation was soon underway.


    It's easy to check a computer program for plagiarism if you have access to the source code. As Rybka isn't open-source (Rajlich claims to have not kept the early versions of Rybka's source code, in any case) such a straightforward comparison is impossible. The only evidence, beyond Rybka's habits at the chessboard, is the data locked away in the compiled, executable app.

    Disassembling Rybka does not get you an exact rendition of the original code. It does, however, reveal the cutting-edge heuristics which determine the machine's playing strength. This inspection was accomplished by Mark Watkins, a Research Fellow at the School of Mathematics and Statistics at the University of Sydney. And according to Watkins, it revealed the evidence of algorithm-cloning that the ICGA sought.

    "We are convinced that the evidence against Vasik Rajlich is both overwhelming in its volume and beyond reasonable question in its nature," wrote the authors of the report, published June 28, 2011. "Vasik Rajlich is guilty of plagiarizing the programs Crafty and Fruit, and has violated the ICGA’s tournament rules"

    The sactions disqualified Rajlich and Rybka from each World Computer Chess Championship they had competed in; banned Rajlich for life from all ICGA events; and awarded the earlier championship prizes to the runners-up. Rajlich was told to return his trophies and prize money.


    Supported by technical work by programmers Ed Schröder and Sven Schüle, Riis now offers several objections to the ICGA's conclusions.

    First, he claims that the parts of Rybka found to be similar to Fruit were relatively insignificant, and that the tournament rule Vajlich allegdly violated is vague and obsolete.

    Pointing out that Rajlich admitted using Fruit's ideas from the beginning—such as in a 2005 interview where he reports that he scrutinized the Fruit source code "forwards and backwards and took many things."— Riis says that any infraction of the rules could not possibly have been an intentional effort to deny Rybka's pedigree.

    Riis also claimed that the status quo in chess programming is just as Levy feared it, with disassembly and algorith-borrowing so widespread that Rybka, as leader of the pack, is more victim than perpetrator.

    His most forceful criticism, however, centered on "fabricated" C code included in Watkins's technical report. Presented as "Rybka", the code is in fact a recreation based upon the disassembled machine code.

    "The ICGA used a report relying on hypothetical code presented as Rybka code to convince others that copying occured, when only the algorithms could have been copied," Riis said.

    Riis also speculated that Rajlich was being attacked due to the competitive success of his work, and that the investigation's unauthorized disassembly of it was itself clearly illegal: "The whole process was an unprofessional disgrace."

    Within a week, the ICGA responded to Riis's report, in the form of a letter penned by Levy and a further technical analysis from Watkins.

    Levy pointed out that, all else notwithstanding, Rajlich still failed to declare Fruit on the competition entry forms, thereby breaking the tournament rules. He also reaffirmed the strength of the forensic case against Rajlich, as revealed by Watkins and others, and said that the panelists knew the report's recreated code was merely for illustrative purposes.

    "He greatly minimizes the magnitude of Fruit/Rybka overlap", Watkins wrote, and "fails to address a number of additional Fruit/Rybka congruences that were detailed by the investigation."

    "Riis omits any mention of the fact that Rajlich had previously plagiarized Crafty in private 2004 versions of Rybka, and furthermore that these versions had little internal similarity to the 2005 Rybka. The latter fact played a significant role in the Panel deliberations, strongly implying 2005 Rybka was a re-write, at the least."

    Riis admits that Watkins uncovered some problems with his response, but remains unmoved: "Spin or rhetoric cannot change the fact that the most basic conditions for a fair trial were absent and the process by which Rajlich was convicted was seriously flawed."


    Gone are the days when human champions could evoke the tension of the cold war. But the chess world's exceptionally intense personages are still not to be trifled with.

    In their long, footnoted reports, the ICGA and Riis segue from complex chess programming issues to insults and back again without skipping a beat. In his four-part feature, for example, Riis embarks on a detour just to mock one Rajlich critic for his relentless torrent of forum posts on the matter. The latest "critical analysis" published by the ICGA likewise finds time to ridicule Riis for his "bleating."

    And what of Rajlich himself? Usually willing to let others argue it out, he recently offered thanks to Riis and other supporters, and said 2012 would see the release of Rybka 5.

    "Soren did a great job detailing the shenanigans pulled during the ICGA's investigation, from stacking the jury to premature public accusations to a comprehensive fabrication of evidence," he wrote at the official Rybka website. "Of course there is a clear influence of Fruit on Rybka. I haven't tried to quantify this influence or compare it to other engines from Rybka's generation. What I can say is that Rybka is original at the level of source code. In the context of source code, original means that the author either typed his own code or typed the code which generated his own code. For the super-geeks, yes, that can be applied recursively."

    This pattern, whereby Rajlich's critics tend to speak of "algorithms" while he speaks of "source code", seems to reflect each side's understanding of copyright law's relevance to the case. Whereas the ICGA considers the algorithms used in chess software to pass tests of copyright-worthiness (explicitly mentioning the Abstraction-Filtration-Comparison Test), Rajlich instead focuses on their expression, insisting that his code is original—an approach that might prevail in a U.S. courtroom, if not the ICGA star chamber.

    "The implementation of ideas and algorithms learned from other programs is universal practice in chess programming," Riis wrote, later adding via email: "You can certainly copyright code containing a formula or an algorithm, or a writeup containing these, but if someone goes in and just steals your formula or algorithm sans code, you can't claim copyright protection."

    This distinction notwithstanding, the ICGA's conception of authorship clearly extends further down, to the algorithms. This is understandable, given that chess is a game with few rules, played under time pressure, where small, efficient programs are the currency of success. Even tiny details may confer an insurmountable advantage on the board.

    In this respect, chess algorithms may be similar to typefaces, recipes and dance choreography: realms largely unprotected by copyright law, but where moral authorship is central to the professional credibility of those who make a living there.

    But if there's one thing both sides seem to agree on, it's that authorship can be a somewhat vaporous thing in the world of chess programming. The ICGA ingestigation, after all, was heralded by Levy's exasperation at the amount of illicit "cloning."

    "[It] not only damages the commercial opportunities for the original programmers, it also steals the kudos of tournament successes," Levy wrote. "Genuinely achieving a great result in a top level chess tournament requires years of painstaking effort by a highly skilled and highly motivated programmer or team of programmers, yet the creation of a clone steals the glory and public acclaim from its rightful owner."

    To Riis, though, the cat has been out of the bag too long, resulting in a "paradigm shift." Computer chess engines now quickly absorb one anothers' innovations: "Everyone in the top tier of chess programming learned from Fruit. Retrospectively, what now seems clear is that Fruit also unwittingly triggered a revolution in the whole ethos of chess programming. From the emergence of Fruit and going forward, the premise within the programming community was that it was perfectly fine to re-use and share ideas and algorithms from leading programs whether they were open source or not.."

    When everyone copies everyone, like members of a highly-competitive research team working together on a single problem, everyone benefits. If the collaborative methods are rotten, however, the balance of power is always vulnerable to accusations of unfairness, betrayal and theft.

    Fruit was open-source, but Rybka was not. Fruit itself went closed-source soon after its initial success. Though Rybka was suspected early of foul play, it took five years for action to be taken; five years in which a shifty world of inconsistently-tolerated disassembly and idea-cloning, outined by Levy and Riis alike, took hold.

    "Its impossible to write a modern chess program without borrowing extensively from other programs or algorithms," said Riis. " ... No serious chess programmer would program a chess engine from scratch ... To the best of my knowledge all of today's top programs either a) started up by taking some existing program apart or b) have liberally used other programs to enhance their own design."

    If as many other leading engines have incorporated Rybka's innovations into their own code as Riis implies, they too may be in a compromised position if the spotlight ever falls upon them: "Rajlich's original ideas have been lifted from various reverse-engineered editions of Rybka again and again and again—his work has been pilfered as comprehensively as anyone's in all of computer chess history."

    "I am completely unconcerned about the reverse-engineering that has been done," wrote one Rajlich critic, Dr. Robert Hyatt, during a forum debate. "Seems like a fair way to 'even the playing field' by forcing a secretive author to expose secrets he has desparately tried to hide."

    But now even that option is off the menu: in its latest versions, Rybka works as an internet service instead of as an application downloaded to a personal computer. As a result, it's now harder to look under the hood for a peek at its inner workings. This could threaten to upend the chess AI scene permanently, and it's easy to understand how frustrating this would be to rivals who tolerated Rybka's loose attitude to authorship so long as they could do likewise.

    Asked if he thought it would be possible to make a competitive, commercial chess engine that remained open-source, Rajlich said that he did: "Of course competitors would quickly catch up, but that isn't much different than releasing an executable. An executable isn't that far from source code in terms of having value to competitors."

    If all this is even slightly true, the most interesting part of Rajlich's punishment is not his disgrace and exile, but the act of public scrutiny forced upon his work. It is a reminder, to everyone, that Letouzey may have been right to begin with.

    / / COMMENTS

    / / / / /


    1. Aren’t they confusing copyrights and patents? Do Fruit’s developers even have patents on their algorithms?

      1.  I am not sure but I recall Fruit was GPL (2.0?). I think that under that license you must at least credit the source or open the source since it uses open content. Either way, I am no expert on that, but it’s very bad etiquette to lift code from somewhere and not credit the source, which Rajlich should have done (even forms part of the rules of that competition! his actions lack ethics no matter what. That he made his stuff a service is pretty suspicious too.)

          1. Regardless of licensing, if Rajlich took *anything* from Fruit and didn’t credit it, he is in violation of the competition’s rules, even if Fruit’s code happened to be purely “public domain”.

      2. They’re not confusing anything: the ICGA is a private body. If they want to say copying an algorithm is not permitted they are free to do so, even if a court of law might view it as being perfectly legal.

          1. Theyy can’t say it’s illegal, but they’re quite free to say it’s against the rules. When they don’t follow the rules themselves, though…

      3. Patents costs thousands of dollars in legal and filing fees. No point in getting a patent on something you’re doing as a hobby and giving away for free. Also, I don’t know that Fruit does any one particular thing that was unique to all other chess engines. Maybe something called “history pruning” but it’s basically impossible to prove that nobody was doing that before (or after) in their closed-source engines.

    2. Both are kind of despicable, but I can see why there was such unanimous hatred towards Rajlich. So, being under suspect, and having Riis claim that stealing code is the norm, makes his program a service so it cannot be stolen from? Also, from his own wording it seems that he took the algorithms from Fruit and modified them so the code “does not read the same”. He obviously added his own stuff, but…
      In one hand, if you distribute open source is for others to be able to use it and learn from it. But Rajlich’s behavior seems to be pretty much abusing that good will for his profit, without giving back at all. Probably not even giving thanks, because he isn’t even citing the source.
      Perhaps it’s because I am a FOSS developer, but Rajlich and Riis make me want to vomit. Even if the other side is not puppies and sunshine.

    3. All I see if a complete waste of brain capital.

      Can you imagine if they were creating code to actually do something more useful to mankind, like untangling complex DNA sequences for more effective cancer drugs, instead of creating a chess program that can beat another chess program in the least amount of moves?

      I can’t think of a better example of a group of people being so insular that they are only useful to themselves. There might be some uses to these algorithms, but I just can’t get over the feeling that this kind of focus could be used better.

      1.  You cannot tell hobbyists what to do with their time, you know. One’s time is one’s belonging.
        And keep in mind that every person on the planet can say the same about your own hobbies. Some might call it a loss of time, or uncool.
        And, you don’t have to agree. Because it’s YOUR time.

      2. Umm, algorithms are the most easily repurposed machines in the entire technosphere.  World of Warcraft is probably 40% A* pathfinding, but you can also use A* pathfinding to do pattern recognition/data mining on fingerprint databases for law enforcement or for finding new features in Hubble photographs.  If some WoW developer came up with something superior to A* then you could almost immediately transfer those gains to all the other applications of A* pathfinding.  Working on any algorithm for any purpose is not at all a waste of “brain capital” since it can be immediately used on any isomorphic problems and quickly retooled to use on problems that are “similar” in certain ways.

        1. Perhaps Johnny’s point was that brain capital is wasted in developing algorithms that are not made available for re-purposing/adaptation?

          1. Based on the wording that’s not the impression I get, though I could certainly have misinterpreted him.  Also, see article re: disassembling and reverse engineering.  If you have the binaries you can get the algorithms.

            1. See article re: disassembling and reverse engineering a bit more. Rybka is now a service so as to avoid distributing binaries.

        2. Your first and final sentences are about right, but otherwise you’re miles off the mark. Agreed, I’m probably being pedantic – but it’s better than spreading factually incorrect bits’n’bobs…

          To suggest WoW is 40% A* pathfinding is pretty wide of the mark – if it were 40% A* then it would be much easier to write a clone of the game. A* might be clever, but it only takes an afternoon to implement it.
          Furthermore there are better search algorithms in lots of instances – see for example IDA* (takes a little longer, uses much less memory), the various hierarchical A* adaptations (quicker and more memory efficient on maps – although not necessarily much use outside of that domain / for general purpose problem search), D* (more efficient if replanning due to local changes) – also A* isn’t really much use (if any) for pattern recognition, for that you probably want to be using machine-learning, certainly not search.

          Next time perhaps you should stick to using some kind of metaphor involving perhaps a car or something? ;)

      3. All the programming advances here get borrowed by programmers for other kinds of software. It’s like NASA developing velcro for space travel. Everyone still knows how to make velcro cable ties and make velcro suits to stick people to a walls after the space missions are over.

      4. I wonder what you do that’s so important to the advancement of mankind? Almost everybody’s job and/or hobbies are irrelevant when viewed in a certain light. What’s the point of professional sports? Or the entertainment industries? etc.

        1. I wonder what you do that’s so important to the advancement of mankind?
          Almost everybody’s job and/or hobbies are irrelevant when viewed in a certain light.

          This is such an intense hobby it just looks like a whole industry to me, not a gig. There’s so much that can help further tech.

          “What’s the point of professional sports?”

          Heh, yeah, what is the point of pro sports? But that’s another discussion. :)

          1. Millions of people play chess and there are naturally several related sub-industries. Books, organizations (basically leagues), manufacturing and selling equipment, and yes, software. There are a number of people who develop chess software professionally, i.e., as their main source of income. There are many more who do it as a hobby.

            I don’t think it’s much different than the industries surrounding, e.g., golf though, so I still find criticism of computer chess as pointless to be unwarranted.

            1. “I don’t think it’s much different than the industries surrounding, e.g., golf though, so I still find criticism of computer chess as pointless to be unwarranted.”

              I didn’t say it was pointless inmy revised statement, I said all of that focus on brain power could be used for something better with the results of it (by open source it, etc)  to help other industries.

              IMO, Golf is not the best analogy because making a better developed golf club, or how to perfect a golf swing like Tiger Woods isn’t going to make the AI of a manufacturing robot in Detroit any better or help with cracking unsolved algorithmic problems that have the potential to create drug therapies to solve cancer.

              But who knows?  Maybe it’s so interconnected now that creating a golf club better will help with streamlined wind tunnel car manufacturing. :)

      5. I stand corrected and great responses everyone!

        I just hope that those algorithms can be used for the greater good for the industry instead of locked up in some code. On the other hand, I understand since a company like Google isn’t going to show their proprietary search engine code for the benefit of mankind. Maybe eventually these chess algorithms will go open source?

    4. I wonder which side is supported by SkyNet?  It’s interest in the development of the strategy algorithms used in our era’s chess programs is well  known.

    5. Fascinating, Rob, thanks for sharing this. 

      While we’re on the subject, can anyone suggest a good IP lawyer?  I want to patent the long division algorithm.  I’m gonna make a fortune!

    6. “Rajlich claims to have not kept the early versions of Rybka’s source code in any case.”

      I don’t believe that one could write a chess program without some sort of version control. The code of those version would make the case a lot easier to solve, so it’s all very suspicious that this code is claimed to be lost…

      1. And conveniently distributed as a service now, if the article is right. So you don’t have an executable to examine. Suspicious.

    7. The painting’s mirror’s reflection of the bearded gentleman is wrong. 

      THAT”s what I thought the fissure in the ‘Chess AI Scene’ was – a time/space fissure.

    8. This is absolutely ridiculous.  These are some of the most technically impressive programs in the world here (at least as far as elegance and mathematics is concerned, if not applicability), and these people are squabbling over things as worthless as *ownership*????  How obnoxious is that!  So WHAT if this random better program has elements of someone else’s innovative but less effective program!  IT’S BETTER.  THAT MEANS IT’S AN IMPROVEMENT.  WHICH.  IS. A. GOOD. THING.

      Good god, it’s simply amazing that the human race ever gets anything done at all.

      1.  That’s true, but credit where credit’s due, and one of the competition rules is crediting whoever you lifted code from.

        1. I guess I just tend to take the long-view on these things, where the successes and failures that happen in the present are minor in comparison to the bigger successes or failures that could happen in the future.   Making it a competition in the first place just feels too short sighted.  Same with the Turing competitions.  I recognize that competition can motivate people, but institutionalized competition can also promote stagnation, as opponents become increasingly unwilling to share beneficial discoveries, and concerns about fairness create artificial barriers that wouldn’t otherwise exist.

          1. As the author of a chess engine I can say that most of the advancements in computer chess in the last ~20 years have been so domain-specific that they don’t really provide much of a benefit to computer science or humankind in general. So it doesn’t matter if all chess programmers work together harmoniously or not. Making a chess engine is a fun hobby, it’s fun to invent secret algorithms that might give your own engine an advantage, and it’s fun to compete with other hobbyists. No sense bemoaning that.

            Second, even if everybody is supposed to be working together on something (as with research science), attribution of discovery is still a huge issue. If you invent a cure for cancer and everybody else copies it and takes credit for it, are you still going to say that credit doesn’t matter?

            1. further to your very valid points, chess is a two-player adversarial game – so by its very nature, pitching one engine against another in a competition just makes sense!

            2. Fair enough.  Chess playing programs are so deeply tied to early advances in artificial intelligence that it’s hard to view them as just fun hobbies that don’t contribute much to the field of computer science anymore.

              I never said credit doesn’t matter, by the way, only that it was a worthless and childish thing to fight over. Especially when it’s ambiguous. I could make analogies to Leibniz and Tesla, since that’s easier to imagine than me inventing a cure for cancer, but it’s not important. Those fights look embarrassing in retrospect, and so will this little chess squabble in time, I am certain. The comparisons to steroids especially struck me as foolish: steroids aren’t allowed in sports because no one in sports is trying to actually *advance* anything, generally-speaking. This, as opposed to individually-speaking, where advancement is simply a honing of the human body in its current evolutionary state. So unless you really think Chess programs have hit their peak; that they truly have nothing left to contribute to human knowledge, then maybe that makes sense to you. But if there’s even a scrap of useful knowledge hiding in there that might help with efficiency or Bayesian analysis, then such “steroids” should be –enforced–, not prohibited.

    9. It should also be noted that Riis is not impartial. he is a moderator on the Rybka forum and has been so for many years.

    10. tl;dr: Stupid rules broken by asshole. No good comes of it.

      If the goal is to create the world’s best chess playing program the rules should mandate that all code is open source and published as part of the program’s entry in the competition. Next year’s competition would be fierce!

    11. Speaking of credit, where’s this article from?  Or did Rob write it?  It kind of looks like the whole thing is in a blockquote, but I don’t see a source.

    12. Brilliant to see a chess story on Boing, come the day we see chess on the English TV.

      There is an extremely strong open source engine called Stockfish, the day this engine beats all others, is the day open source is proved to be the best way forward for the human race.

      Coders please support the project here.


      Lots of chess links here.





      1. So, you are saying that there is nothing that you can do better than your parents? You are copied genetic code yourself.

    13. As an AI schooled programmer and a chess player I really enjoyed reading this article ! :) :) :)

    14. Can I ask who wrote this? It’s pretty unusual for BB to post something this long. Was it you Rob?

    15. What is not mentioned is the history of how Rybka evolved.  The program used to compare to Fruit was Rybka 1.0 beta and not the Rybka that played in the ICGA tournament, that is a point that is quite important since in the released Rybka 1.0 beta there is a text file that clearly mentions Fruit as well as other engines and authors as having a major influence.  How else would someone go about developing a chess engine?  Clearly looking at open source code is the first step to get started.  Also Rybka was stripped of all titles by the ICGA, including later titles won by later engines such as Rybka 3.0, which has been intensively checked and RE and deemed to be purely original.  The massive breakthrough in computer chess was Rybka 3.0, and while Rajlich might have made good use of available open source engines to build Rybka, he managed to come up with ideas and code that dramatically increased the strength of a chess engine to levels never thought possible.  Rybka 3.0 has since been RE and released as public domain code (Ippolit) and all chess engines have had a dramatic boost due to Rajlich’s work.  It is ironic that many of the programmers that found it plausible to claim that Rajlich was guilty of “plagiarizing” code, see nothing wrong with making good use of Rajlich’s RE code in their own engines.

    16. Much harder than producing a chess program would be writing about the Rybka disupte in such a way that most of us can understand it…..

    17. From an IP law perspective, copyright intends to restrict use, and allow the author the “fruits” of his labor for a period of time. If material from another is used in the copyright, it is a “derivative copyright” and the borrowed portions must be borrowed with permission. Copyright does not protect ideas, only a particular expression of them. Before copyright, use of other’s expressions (“borrowing”) was prevalent throughout history (i.e., Homer’s Odyssey), and many argue that process advanced society. Rap music followed this approach until copyright experts from music companies shut down “sampling“in the 90s.

      The open source movement says ideas and even expressions should be “free” and freely used, only subject to certain rules contained in form “open source licenses” which, while granting free use, normally still require proper credit being given for any borrowing. Here the legal issue is one of the rules of the International Computer Games Association as to open and closed source use, and cproper redit, but the simple moral issue is whether full credit was given, or, to say it differently, too much credit claimed. The contests confuse these issues, it seems.

      The latter issue, moral right, may be answered from three statements in the article: “Rybka’s was a closed-source product, its code unavailable for inspection”; “Rajlich claims to have not kept the early versions of Rybka’s source code in any case”; and “What I can say is that Rybka is original at the level of source code”.

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