Database
A chess database is a searchable collection of games, stored in a standard format, that lets a player look up positions, study opponents, and see how often moves have been played and what results they scored.
Also called: game database
A database is where a serious player keeps and searches games. Most are stored as PGN files and opened in a program that can sort, filter and search them. You can filter by player, by opening, by rating range, by result, or by the exact position on the board.
The search by position is the feature club players underuse. Reach a middlegame you do not understand, search it, and you see which moves strong players chose and how the games ended. Opening statistics come from the same idea: a tree of moves showing how often each was played and how it scored.
A common mistake is treating the numbers as the truth. A move with a high score may simply be popular among stronger players, and a small sample proves little. Another is collecting thousands of games and reading none of them.
A practical habit is to keep one small personal database of your own games, tagged by opening and by the mistake that decided each loss. Before a tournament, search for your next opponent's games and look at the openings they repeat. Then pick a handful of model games per opening and replay them slowly instead of skimming many.
Compare it with Opening explorer. An opening explorer is a tool that shows, for any position reached from the start, which moves players have chosen in past games and how often each move led to a win, draw or loss.
Also worth reading is PGN. PGN is a text-file standard for chess games: header tags name the event, players and result, then the moves follow in algebraic notation, so databases, engines and websites can all import the same file.
Compare it with Opening preparation. Opening preparation is the work done before a game to know your chosen lines well, including studying your own repertoire and checking the likely choices of a specific opponent.
An engine can tell you what "Database" means for a position, but not which mistakes you keep making; a first lesson with George Li reviews your games and finds those.
Related terms
An opening explorer is a tool that shows, for any position reached from the start, which moves players have chosen in past games and how often each move led to a win, draw or loss.
A game review is an automatic engine pass over a finished game that marks each move, shows how the evaluation changed and points out the turning points, mistakes and missed chances.
Opening preparation is the work done before a game to know your chosen lines well, including studying your own repertoire and checking the likely choices of a specific opponent.
Opponent preparation is the work of studying a known opponent's past games and habits before a round so you can choose openings and plans that steer the game toward positions where they are less comfortable.
PGN is a text-file standard for chess games: header tags name the event, players and result, then the moves follow in algebraic notation, so databases, engines and websites can all import the same file.
Guides that go further
What to decide first, the questions to ask, what a first lesson should show and the red flags to avoid.
How much does chess coaching cost?
Published rates for private, group and subscription chess coaching, with the source and the date of each.
A game review, a read on your level and a written study plan from George Li.
Want to spot this in your own games?
A first lesson starts with your games: George reviews them and builds a study plan around what he finds.