A tablebase is a database of endgame positions computed backward from checkmate, giving the exact result and a perfect move for every position it covers.
Tablebases are built by retrograde analysis: the computer starts from every possible checkmate and works backward, labeling each position as a win, draw or loss with the precise distance to the end. Within its piece limit, a tablebase does not evaluate; it knows.
Every position with up to seven pieces on the board, kings included, has been solved. The results hold surprises: one seven piece position is a forced mate in 549 moves, a win no human could find and one that collides with the fifty move rule long before it finishes.
In practice, engines probe tablebases the moment few pieces remain, and analysis sites show their verdicts alongside evaluations. For players they are a brutal training partner: defend queen against rook versus a tablebase and it will punish every single slip perfectly.
No. Tablebases give perfect play only once seven or fewer pieces remain. Full chess starts with 32 pieces, and solving it is far beyond any current or foreseeable computing power.
Two common formats. Nalimov tables store the exact distance to mate, while the newer Syzygy tables store enough to play perfectly while respecting the fifty move rule, in far less space. Modern engines mostly use Syzygy.
BetterChess is a practice tool — we make no guarantee you'll reach 1800 or any rating. Definitions are standard chess terminology; every diagram position is checked legal with the same engine the board runs.