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Syzygy endgame tablebases

Draw by insufficient material

The game is drawn because with the remaining material no sequence of legal moves can lead to a checkmate.

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Syzygy tablebases

About

Syzygy tablebases allow perfect play with up to 7 pieces, both with and without the fifty-move drawing rule, i.e. they allow winning all won positions and bringing all drawn positions over the fifty-move line.

The tables provide WDL and DTZ information. Forcing captures or pawn moves while keeping a win in hand ensures that progress is beeing made.

DTZ optimal play is unlike the shortest way to mate, because DTM does not account for the fifty-move drawing rule: Sometimes it is better to reset the fifty-move counter than to go for the shortest mate.

6-piece tables were released by Ronald de Man in April 2013, including probing code and the generator.

From May to August 2018 Bojun Guo generated 7-piece tables. The 7-piece tablebase contains 423,836,835,667,331 unique legal positions in about 18 Terabytes.

Selected positions

Download

If you want to use tablebases in a chess engine you certainly need a local copy.

Most of the time (during search) only WDL tables are used. Keep these on SSD storage if you can. DTZ tables are generally only used to finish the final phase of the game ("at the root").

PiecesWDLDTZTotal
3-5378.1 MiB560.9 MiB939.0 MiB
667.8 GiB81.4 GiB149.2 GiB
78.5 TiB8.3 TiB16.7 TiB

Generating the tablebases requires time and resources. It is more efficient to download them via BitTorrent or from a mirror:

Contact

Feedback via mail, bug reports and pull requests are welcome.