During the last two years the engine has been improved in almost all areas. One major theme has been the understanding of the attack on the king. The new Rybka 4 is in this case more precise and reliable than its predecessor. At the same time the search function now operates more quickly and efficiently and the evaluation function delivers even more spot-on judgments. As for the playing style, Rybka 4 logically continues the development of the past few years. Thanks to further development in the tactical area too, the new Rybka 4 will be indispensable for all those who work and analyse with chess engines. Rybka 4 is delivered with the new user-friendly Fritz 12 interface and contains a database of 1.5 million games and includes CLASSIC membership for playchess. com for one year.

System requirements: Minimum: Minimum: Pentium III 1 GHz, 512 MB RAM, Windows Vista, XP (Service Pack 3), DirectX9 graphics card with 256 MB RAM, DVD-ROM drive, Windows-Media Player 9, internet access (playchess. com, updates and activation). Recommended: PC Intel Core 2 Quad, 2.4 GHz, 3 GB RAM, Windows Vista or Windows 7, DirectX10 graphics card (or compatible) with 512 MB RAM or more, 100% DirectX10 compatible, sound card, Windows Media Player 11, DVD ROM drive and internet access (playchess.com, updates and activation).

The activation of the program requires internet access.