ChessBase

Dutch Defence Powerbase 2020 is a database and contains a total of 7890 games from Mega 2020 and the Correspondence Database 2020, of which 688 are annotated.

The major part of the material on which the King's Gambit Powerbook 2020 is based is sourced from the engine room of playchess.com: 30 000 games. Another 3500 games from Mega and from correspondence chess have been added to this corpus.

King's Gambit Powerbase 2020 is a database and contains a total of 2531 games from Mega 2020 or the Correspondence Database 2020, of which 112 are annotated.

The Ben-Oni Powerbook 2020 consists for the greater part of engine games (44 600), to which has been added high-value material from Mega and the Correspondence Database (23 600).

The Benoni Powerbase 2020 is a database and contains a total of 5955 games from Mega 2020 or the Correspondence Database 2020, of which 796 are annotated.

The Volga Benko Gambit Powerbook 2020 is based on over 21 000 games from the engine room of playchess.com and also 12 000 games from Mega 2020 and the Correspondence Database 2020

Volga Benko Gambit Powerbase 2020 is a database and contains a total of 4056 games from the Mega 2020 and the Correspondence Database 2020, 307 of which are annotated.

The Najdorf Powerbook 2020 has a tree structure which is based on 3.69 million computer chess games played in the engine room of playchess.com.

The Sicilian Najdorf Powerbase 2020 is a database and contains 10119 games from the Mega 2020 and the Correspondence Database 2020, 1010 of which are annotated.

The greater part of the material on which the Rossolimo/Moscow Powerbook 2020 is based comes from the engine room of playchess.com: 226.000 games. This imposing amount is supplemented by some 25 000 games from Mega and from Correspondence Chess.

The Rossolimo-Moscow Powerbase 2020 is a database and contains a total of 8111 games from Mega 2020 or the Correspondence Database 2020, of which 575 are annotated.

The major part of the material on which the Caro-Kann Powerbook 2020 is based is taken from the engine room of playchess.com: 725 000 games. To that imposing corpus we have added another 48 000 games from Mega and from correspondence chess.

Caro-Kann Powerbase 2020 is a database and contains a total of 8413 games from Mega 2020 or the Correspondence Database 2020, of which 699 are annotated.

The major part of the material on which the Grünfeld Defence Powerbook 2019 is based comes from the engine room of playchess.com: 219 000 games. To this imposing mass we have added another 60 000 games from Mega and from correspondence chess.

Gruenfeld Defence Powerbase 2019 is a database and contains 9358 top-class games from Mega 2020 and the Correspondence Database 2020, of which 1090 are annotated.