Syzygy
Syzygy tablebases are endgame databases that store perfect-play results and distances for all positions with up to seven pieces, enabling engines to play flawlessly once few pieces remain.
- Category
- Endgames
- Also in
- Computer Chess
- Difficulty
- Advanced
- Also known as
- tablebases, endgame tablebases, Syzygy tablebases, Syzygy bases, 7-piece tablebases, WDL tables, DTZ tables
Syzygy tablebases are endgame databases that contain every legal position with up to seven pieces and the exact result (win, loss, or draw) with perfect play from each of them. They also record the distance to zeroing the 50-move counter (DTZ), allowing engines to convert a winning position as quickly as possible without allowing a draw by the fifty-move rule.
An engine that has access to these files can instantly look up the correct move once the board reaches a tablebase position. No calculation is required; the result is already known. This removes all error from the final phase of the game.
Syzygy files come in two complementary sets. The WDL files give only the game outcome and are small enough to keep in memory. The DTZ files supply the additional information needed to avoid the fifty-move rule and are usually read from disk only when a conversion is required.
Because the files are generated by exhaustive backward induction from terminal positions, every move the engine plays from a Syzygy position is theoretically perfect. In practice this means that an engine using 7-piece Syzygy will never misplay a rook and pawn ending or fail to convert a theoretically won queen ending.
Storage and access requirements grow rapidly with each added piece. The complete 7-piece set occupies roughly 18 terabytes, so most users keep only the 5- or 6-piece files on their machines and rely on online servers or selective probing for the largest positions.
Frequently asked questions
- What are Syzygy tablebases?
- Syzygy tablebases are endgame databases that store the exact result and distance-to-zeroing values for every legal position with up to seven pieces.
- What is the difference between WDL and DTZ Syzygy files?
- WDL files give only the win, loss, or draw outcome and are small enough to keep in memory, while DTZ files supply the additional data needed to avoid fifty-move-rule draws.
- How do engines benefit from Syzygy tablebases?
- An engine with Syzygy access plays any tablebase position flawlessly by direct lookup instead of searching.
- How many pieces do the current Syzygy tablebases cover?
- They include all positions with seven pieces or fewer.
About the reviewer
James came to chess late, and he'll tell you that's part of the appeal. He picked up the game in his thirties, mostly out of boredom, and found something he wasn't expecting: a puzzle that never quite runs out of new…