Glossary
A consolidated A-Z reference for chess terms used across this site. Where a term already has a full write-up elsewhere, its entry links there instead of repeating the explanation.
Alekhine's GunRead more →
Stacking a queen behind two rooks on the same open file, so all three pieces' power bears down the file at once. Named for Alexander Alekhine's use of the formation.
Back-Rank MateRead more →
Checkmate delivered along a player's own back rank, when their king has no escape because its own pawns block every forward square.
Bishop PairRead more →
Holding both bishops (one light-squared, one dark-squared) while the opponent has lost one — a small, real long-term advantage, especially in open positions.
CastlingRead more →
The single move that relocates both the king and a rook at once, for king safety. See the King's page for the full legal requirements.
Discovered CheckRead more →
A check revealed by moving a piece out of the way of a friendly long-range piece, rather than by the moving piece itself.
ECO Code
A classification code (A00 through E99) from the Encyclopaedia of Chess Openings used to catalog and reference specific openings and variations.
En PassantRead more →
"In passing" — a special pawn capture available only immediately after an enemy pawn advances two squares past a square your pawn attacks.
Exchange, The
The specific material difference between a rook and a minor piece (bishop or knight). "Winning the exchange" means trading a minor piece for the opponent's rook.
FianchettoRead more →
Developing a bishop onto the long diagonal (typically g2/b2 or g7/b7) after moving the adjacent knight's pawn.
FIDE
The Fédération Internationale des Échecs (World Chess Federation), the international governing body that organizes the World Championship, awards titles, and maintains official ratings.
ForkRead more →
A single piece attacking two or more enemy targets at once.
GambitRead more →
An opening that deliberately offers material, usually a pawn, in exchange for faster development, central control, or attacking chances.
Grandmaster (GM)
The highest title FIDE awards to individual players, earned through a combination of rating thresholds and strong results ("norms") in qualifying tournaments.
Initiative
The state of being the side making threats and forcing the opponent to react, rather than the side reacting — often more valuable in the short term than material.
Isolated Queen Pawn (IQP)Read more →
A central pawn, usually on the d-file, with no friendly pawn on either adjacent file to support it.
J'adoube
French for "I adjust" — said before touching a piece purely to straighten it on its square, without committing to move it under the touch-move rule.
OppositionRead more →
The relationship between two kings facing each other with exactly one square between them — whoever is NOT forced to move first usually gains the advantage.
OutpostRead more →
A square, usually for a knight, that can never be attacked by an enemy pawn — turning a minor piece into a long-term positional asset.
Passed PawnRead more →
A pawn with no enemy pawn able to stop its march to promotion — often a decisive endgame asset.
PinRead more →
Attacking a piece that has a more valuable piece (or the king) directly behind it on the same line, so it can't safely move.
ProphylaxisRead more →
Preventing an opponent's plan before it can even begin, rather than reacting to it after the fact. Closely associated with World Champion Tigran Petrosian.
SkewerRead more →
The pin's mirror image: attacking a valuable piece that must move, exposing a less valuable piece directly behind it.
Smothered MateRead more →
Checkmate delivered by a knight to a king that is boxed in entirely by its own pieces, unable to move anywhere to escape.
Tempo
A single move, considered as a unit of time. "Gaining a tempo" means making a move that develops your own position while also forcing the opponent to spend a move reacting.
Touch-Move Rule
The official rule that if a player deliberately touches one of their own pieces, they must move it if it has any legal move (see also J'adoube).
Windmill (Seesaw)Read more →
A repeating discovered-check combination where a rook and bishop battery swings back and forth, capturing material on every single swing.
ZugzwangRead more →
German for "compulsion to move": a position where every legal move actively worsens the player's own position, but chess offers no way to pass.
ZwischenzugRead more →
German for "in-between move": inserting an unexpected, more urgent threat before making an otherwise-expected move like a recapture.