Openings Encyclopedia 2011 includes theoretical material on every opening, a user-friendly and detailed classification of variations, a quick search option and an option for analyzing games and positions.Openings material is based upon 500,000 of expert evaluations, 8,000 annotations to key moves , 40 million of evaluations by Rybka engine, and database of 4,350,000 games as of April 1, 2011.