Chess Program Players Use to Cheat Was, Itself, Cheating

The world's most advanced chess engine is barred from electronic competition

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When people cheat at chess, they usually use computers. When computers cheat at chess, they use... other computers, it seems. That's what officials are accusing the maker of Rybka, the world's most advanced chess program, of doing in competitions where he won money and accolades. Cheating at chess has become something of a scourge recently, with players at some of the world's top-level competitions getting caught using computer programs to help them gain an edge. A favorite for this practice: Rybka, of course.

Today, it came out that the International Computer Games Association had officially stripped Rybka's programmer, Vasic Ralich, of the four titles he has won since 2007 in the World Computer Chess Championships. He's also been ordered to give back his prize money. Officials say Ralich plagiarized programming script used to power competing programs Crafty and Fruit, and that they've proved it by analyzing and reverse-engineering Rybka's gameplay, Extreme Tech reports. "Curiously, ICGA isn’t even disqualifying Rybka because it copies Fruit--rather, it’s simply upset that Rajlich claims his engine is original, and refuses to give credit where it’s due."

To come to this rather epic and libelous conclusion, the ICGA assembled a 34-person panel of programmers who have competed in past championships to analyze Rybka. Unfortunately, Rybka’s source code has never been available, so reverse engineering and straight-up move-evaluation comparison was used to analyze the originality of Rajlich’s chess engine. The panel unanimously agreed that newer versions of Rybka are based on Fruit — and worse, that the early beta versions were based on Crafty, another open-source chess engine. Rajlich has always claimed that Rybka is original — even when confronted with the findings of the report by the president of the ICGA.

In 2009, Azerbaijani grandmaster Shakhryiar Mamedyarov accused Russian Igor Kurnosov of cheating at the Aeroflot open using Rybka to dictate his moves. In 2007, Krzysztof Ejsmont was accused of using Rybka to cheat at a tournament in the Polish town of Police, at the Tadeusz Gniot Memorial tournament. Even Veselin Topalov, one of the world's top players, was suspected of using the program to cheat in San Luis in 2005. All these cases came about when officials compared players moves to Rybka's after the fact, and found suspiciously high matches.

Of course, there are a lot of chess programs out there, and Rybka has nowhere near cornered the dishonesty market for live players. The most famous scandal in recent memory had three top players conspiring to cheat using an elaborate system of text messages, software, and body language at the 2010 Chess Olympiad in Siberia. They used a program called Firebird.

Now that Rybka has been disgraced, however, perhaps it will become the go-to for those who would cheat. Here's a suggestion for a new tagline: "Rybka plays to win, and so should you."

This article is from the archive of our partner The Wire.