Chess Terms


There have been many commercial engines since chess computers stepped onto the scene, but Rybka is known as one of the strongest. It defeated multiple strong grandmasters in various matches with odds and won multiple World Computer Chess Championship titles. Let's learn more about this engine.

Here is what you need to know about Rybka:

What Is Rybka?

Rybka, which means "little fish" in slavic languages, is a computer chess engine that was developed by IM Vasik Rajlich in the early 2000s. Rybka is commercially partnered with Chessbase and has a signficant list of accomplishments, including multiple Dutch open computer chess championships, multiple CCT event wins, and four consecutive World Computer Chess Championship titles.

Rybka chess engine
DVD cover for Deep Rybka 4. Image:

Rybka Accomplishments

Rybka earned its first major victory at the 15th International Paderborn Computer Chess Championship in 2005 ahead of Shredder and many other powerful engines. In 2006 Rybka tied for second alongside Shredder at the World Computer Chess Championship. It also won its first of multiple Dutch open computer chess championship titles in the same year.

In 2007 GM Roman Dzindzichashvili played an odds match where Rybka was Black in every game and gave pawn odds—the match was drawn 4-4. Rybka also faced GM Jaan Ehlvest with pawn odds and won handily. In 2008 Rybka faced GM Joel Benjamin where the odds were different: Benjamin had White in every game and was given draw odds—Rybka won this match 6-2.

Rybka won the World Computer Chess Championship in 2007, 2008, 2009, and 2010—it was viewed as the strongest engine on the planet at this time.

Rybka Controversy

Unfortunately, a strange controversy occurred, and Rybka was stripped of its World Computer Chess Championship titles and banned from future events by the International Computer Games Association (ICGA).

rybka chess engine
Rybka's developer IM Vasik Rajlich in 2006. Photo: Wikimedia, CC.

The ICGA claimed that Rybka had plagiarized code, but Rybka's developer Rajlich denied this allegation, and the issue was renewed. Chessbase published a series of articles claiming that the ICGA's decision was incorrect, and an appeal was made. In 2015 the FIDE Ethics Commission sided with Rajlich—an unusual story in the world of chess.

Rybka Games

Like all powerful engines, Rybka has many impressive games. Here is a 25-move victory over GM Mauricio Flores Rios where we see what happens when an unsound gambit is tried against Rybka:

In this second game example, we see Rybka tear apart the engine "Jonny" after a tame opening in just 21 moves! The attack comes swiftly and mercilessly after Black grabs the exchange with 16...Bxe1:


You now know what Rybka is, what it has accomplished, and more. Head over to and watch top engines battle for the Computer Chess Championship at any time on any day!

Explore More Chess Terms