The chess world on Monday plunged into controversy when World No. 18 Shakriyar Mamedyarov of Azerbaijan withdrew from the Aeroflot Open in Moscow, a top Grandmaster tournament, after accusing his opponent of cheating with the help of a computer programme.
Mamedyarov refused to take further part in the event after losing to Igor Kurnosov of Russia in the sixth round.
Mamedyarov, the top seed, was sharing the lead after five rounds but was crushed by joint-leader Kurnosov.
This is the first instance a top GM has quit an event alleging cheating, though it is not the first time of one accusing his opponent of fraud.
The last cheating controversy was the Toiletgate scandal of 2006 when Vaselin Topalov accused Vladimir Kramnik during their World Championship unification match in Elista.
The toilet figures in this case too as Mamedyarov accused Kurnosov of leaving the board after every move and going to the toilet.
The Azerbaijan player claimed he analysed the moves with the help of a computer and found that a powerful chess engine, Rybka, recommended exactly same moves.
In a letter to the organisers, Mamedyarov said, "After suspicion of unfair play on move 14, I offered a draw, he refused. We quickly played 11 moves (and) on the 12th I played a move which confused my opponent.
The next moves from him were given as first choice by Rybka, which quickly allowed him to win the game.
"Due to this series of suspicions, having to do with the unusual behaviour of my opponent, Igor Kurnosov, I hereby lodge a protest and refuse to continue participation in the tournament," the letter said.
Incidentally, Mamedyarov, whose name does not figure in next round pairing, is rated 2724 and more than 100 points higher than Kurnosov (2602) in the rating list. But the fact that his moves were the same as recommended by Rybka or that he left the board after every move is not proof enough of cheating and Mamedyarov will have to come up with concrete evidence against Kurnosov, who is leading the event with five-and-a-half points from seven games.