ChessBase

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 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 Pirc Defence Powerbook 2019 (including the Modern Defence) consists for a greater part of engine games (160 000), to which has been added high value material from Mega and the Correspondence Database (46 000).

Pirc Defence Powerbase 2019 is a database and contains a total of 8423 games from Mega 2019 or the Correspondence Database 2018; of these 709 are annotated.

The Queen's Indian Powerbook 2019 has a tree structure which is based on a mixture of over 350 000 complete chess games played in the Engine room of playchess.com and the best games played by humans (50 000).

Queen's Indian Powerbase 2019 is a database and contains 9048 high level games from Mega 2019 and the Correspondence Database 2018, of which 593 are annotated.

The major part of the material on which the Sicilian Kalashnikov Powerbook 2019 is based comes from the engine room of playchess.com: approximately 18 000 games. To these have been added another 4500 games from the Mega database and from correspondence ch

Sicilian Kalashnikov Powerbase 2019 is a database which contains a total of 2724 games from Mega 2019 or the Correspondence Database 2018, of which 157 are annotated.

The Colle-Zukertort Powerbook 2019 contains mainly engine games (53.500) and high-level material from the Mega and the Correspondence Database (4.500).

The Colle-Zukertort Powerbase 2019 is a database and contains 4703 games from the Mega 2019 and the Correspondence Database 2018, 75 of which are annotated.

The Torre Attack Powerbook 2019 is based on a mix of 37,000 computer games and 13,000 games from the Mega database and the Correspondence Database.

The Torre Attack Powerbase 2019 is a database and contains 6370 games from the Mega 2019 and the Correspondence Database 2018. 280 games are annotated.

Bird Opening Powerbase 2019 is a database and contains a total of 3558 games from Mega 2019 or the Correspondence Database 2018, 97 of which are annotated.

Good material on the Bird Opening is rare. So the Powerbook on its basis of just 58 000 games is welcome; the majority were played by engines.