Based on more than 1.8 million games, of which a mere 5% played by humans, the related areas of the Slav and Semi-Slav have been brought together in this Powerbook. Interesting statistical conclusions can be drawn since where human theory only throws up a dozen games, Powerbooks often reach numbers in the thousands.
The pure Slav – in the beginning doing without ...e6 – has changed. After 3.Nf3 Nf6 4.Nc3 dxc4 5.a4 the most frequently played move by far is still 5...Bf5, but the reply 6.Ne5 tends to set Black problems more than the alternative 6.e3. The long classical variations after 6.Ne5 Nbd7 7.Nxc4 Qc7 8.g3 e5 9.dxe5 Nxe5 10.Bf4 can be studied very well with the Powerbook. Here it is difficult for Black to equalise completely and so recently he has been deviating earlier: with 7...Nb6 8.Ne5 a5 or even on move 5 with 5...e6 6.e3 c5 – both lines are better from a statistical point of view though Black nevertheless has to work for equality. But in engine chess the Semi-Slav is the much bigger opening. Our Powerbook based is based on over 600 000 games from the sharp Botvinnik Variation with 5.Bg5, and there are even more after 5.e3. After 5...Nbd7 the move 6.Qc2 has replaced the classic Meran continuation 6.Bd3 as the main move. After 6.Qc2 Bd6 7.Bd3 0-0 8.0-0 dxc4 9.Bxc4
now 9...b5 is again the main move, though the statistics demonstrate that Black has several playable continuations, but never completely equalises in any of them. The Slav and Semi-Slav Powerbook 2021 is an openings book which can be used with Fritz or ChessBase. It does not contain any further database – so there are no games included.