The Rybka4 opening book is a high-class compilation of opening theory. It was developed for the world‘s strongest chess entity - 100 cores cluster Rybka and program Rybka4 and will maximize the program‘s playing strength.

The choice of variations in the book is well suited to the style of the program, and the book has been fine-tuned and checked in thousands of games.

The Rybka Book include 17 million positions and over 700.000 games, which were selected from following sources: TOP human practice, correspondence chess games and computer chess games (up to April 2010).

And this is only the starting point: the value of the book lies in over 700 original analysis and move choices, which lead to a re-evaluation in many critical points of modern theory. This makes it useful for tournament and correspondence players alike.

The book contains a lot of computer-checked analysis never published anywhere before. The author of the Rybka4 book is Jiri Dufek (national master, FIDE 2276, ICCF IM 2579), one of the world‘s leading experts in chess opening theory.

Jiri Dufek has been on the Rybka team since summer 2009, and his preparation is used in all official events after this date, which Rykba won. During World Championship match between Vishy Anand and Veselin Topalov worked as second of Veselin Topalov.

In his long chess career he won twice Czech Correspondence Team Chess Championship and wrote together with Roman Chytilek book Beating the French defence (in Czech only).

System requirements: Pentium 1 GHz, 512 MB RAM, Windows7, Vista or Windows XP (Service Pack 2), CD ROM drive, WindowsMedia Player 9, Rybka4, Deep Rybka4, Fritz12, Shredder 12 or Hiarcs 12