Blunder — what it means in chess
A serious mistake that loses material or the game.
A serious mistake that loses material or the game.
A blunder is a move bad enough to change the result of the game — a hung piece, a missed mate, a winning position handed back. Every player makes them, at every level; what changes with strength is the frequency and the size. Annotators mark a blunder with a double question mark, and the symbol carries no judgment about the player, only about the move.
Most blunders come from a short list of causes: moving too fast, calculating an intended sequence and playing a different one, relaxing in a winning position, and time trouble. The last of these is why clock management is a chess skill and not an accessory. The practical defense is a final scan before every move — checks, captures, and threats, in that order — done even when the move seems obvious. Especially when the move seems obvious.
A blunder is also an invitation: a lost position is not a finished one while the opponent still has moves to make, and the swindle is the art of offering them chances to return the favor. Your rating is not a record of your best chess — it is a record of how rarely you produce your worst.
The Endgame Society glossary defines more than 240 chess terms — rules, notation, tactics, strategy, pawn structures, endgames, and openings — in language a beginner can act on rather than dictionary shorthand.