For the Queen’s Indian Powerbook we insisted on an average Elo rating of at least 2300. This meant that 50 000 games from Mega and Correspondence Chess met the threshold for inclusion in the Powerbook, supplemented by over 350 000 games from the engine room of playchess.com – a total of 403 000 games. For White the Queen’s Indian represents a solid alternative to the Nimzo-Indian: there is no doubled pawn on c3, positional understanding counts for more than rote learning of variations. In top chess we can see a slight trend towards 4...Bb7, with 4...Bb7 and 4...Ba6 being played equally frequently. In the Powerbook, on the other hand, 4...Ba6 dominates. After that there is a clear main variation with the following most frequently played moves: 5.b3 Bb4+ 6.Bd2 Be7 7.Bg2 c6 8.Bc3 d5 9.Ne5 (this leads to the exchange of a pair of knights, so recently players have been avoiding it) 9...Nfd7 10.Nxd7 Nxd7 11.Nd2 0-0 12.0-0 Rc8 13.e4
and in this position humans, including the greatest experts Sergei Karjakin and Peter Leko, have moved to a position of no longer playing 13...b5, but rather 13...c5. According to Powerbook there is no basis for that: 13...b5 has super statistics; on account of the high number of games played both continuations represent good material for study.