In the 2nd and 3rd round of the 7th international WCC in Sofia, Bulgaria on October 26-30 2012, a Rybka Free-style single game ended in a draw. Rybka Free was playing with Black to prove to the community that he can play against the world's best programs. Rybka Free-style was DM (Deep Rybka 5.4) by sergei angelov (2010-04-12 17:54:10), it was referred to as the \"WCC chess project\". The game was prepared with the official Rybka Free-style \"spider\".
Rybka Free-style has 10 start positions, 6 starters and 4 of them are best-used. The exchange sacrifice 55 moves in is one of the most interesting positions that Rybka Free-Style has played. In the start, Rybka Free-Style's, Black has a poor and passive side-to-side and forward pawn-front. Not expecting any trick Rybka Free-Style's, opens with 1.34e4 and Rybka Free-Style successfully explores the top-side.
In November 2006, , after a few Rybka users asked for movement to the right, Vasik Rajlich started working on the Rybka 2.4 engine, the first major rewrite of the Rybka engine since its first public appearance. During this beta-test period, Rybka 2.4 was included to the single-player chess engine lineup of ChessBase and the Rybka price tag was removed as well. the engine got the first major re-design which included a major rewriting and the development of a new \"middlegames module\", which made Rybka a digesting engine, capable to analyze middlegame positions not only deeply, but also quickly. After this beta-test period, the new package Rybka 2.4.3 was released and since then 2.5x have been released with new features and play-wise improvements. 7211a4ac4a