In January 2009, Igor Kurnosov was accused by his opponent of cheating in a game because Igor’s moves matched the recommendations of the computer program Rybka until move 16.

Now the designers of Rybka have been accused of cheating, i.e. copying routines from two of its silicon competitors, Crafty and Fruit. Rybka has now been banned from competition, and the ICGA wants the trophies and prize money collected for its previous winnings (the last four world chess championships) returned.

The amusing part is that both Crafty and Fruit are open source; the allegation is not that the authors copied something, but that they didn’t acknowledge the copying, as per GPL terms (the disqualification is because computer programs in Chess competitions must be original work).