Rybka 4 - the strongest to date chess program in the world. Since its publication, the program has won all the tournaments in which participated, regardless of the time management and membership. To date, the most severe rating of the tested versions of fish, more than 3300. What else to say, if the rating of the strongest rated grandmaster now stands at 2812! This program won the minds of all players of the world, without it is now difficult to analyze any position.