Complaints against the Chess programs LOOP and THINKER

David Levy : ICGA President

The ICGA has received formal complaints against the Chess programs LOOP and THINKER, both of which have participated in the World Computer Chess Championship. LOOP was entered by Fritz Reul into the 2007 WCCC in Amsterdam. THINKER was entered into the 2010 WCCC in Kanazawa.

The nature of the complaints is the same in both cases, namely that the programs violated ICGA Tournament Rule 2, which states:

 “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.”

As is now well known, the ICGA takes breaches of Rule 2 extremely seriously. In each of these two cases, in the first instances, the ICGA attempted to make contact with the programmers concerned in order to ask for their comments on the allegations against them. In neither case were we successful – emails to their last known email addresses were unanswered, similarly emails sent via known friends and/or colleagues.

The ICGA then asked an independent expert, Mark Watkins, to investigate both programs.  Mark is a member of the Computational Algebra Research Group at the University of Sydney. He had previously carried out comprehensive examinations for the ICGA of the program Rybka and other programs. Mark’s findings are reported on the ICGA investigation wiki at: and at

Here we present extracts from the first section of each of Mark Watkins reports.

Loop  “The version examined here is Loop 2007 (64-bit), which was released at approximately the same time as the WCCC. There is notable similarity to Fruit in the evaluation function (other components were not examined).”

Thinker “The versions examined here are Thinker 5.4d Inert (March 2009), and Thinker 5.5.4, entered into Leo Dijksman’s WBEC tournament in January 2011. The first appears to derive from Strelka 2 (thus Rybka 1, and relating to Fruit 2.1). The second appears to derive from IvanHoe (thus partially Rybka 3).”

Based on the above mentioned reports by Mark Watkins the ICGA is convinced that, at the very least, both Fritz Reul and Kerwin Medina have a case to answer. Depending on how Reul and/or Medina respond to these allegations the ICGA might decide to conduct further investigations and/or take some form of strong sanctioning action against the programmers.  However, the ICGA does not intend to proceed further along the route to strong sanctions for the time being, in order to give these programmers more time in which to make contact with the ICGA President and present their defence to the allegations. If either or both of these programmers fail to do so by December 31st 2014, or refuses to do so, the ICGA will disqualify them from all their results in ICGA events.  In the meantime the ICGA has decided to suspend both Fritz Reul and Kerwin Medina from participation in all ICGA events until such time as they have made contact and offered a defence.

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