Chess Term Glossary

Chess Term Glossary

Reference for correct usage of chess terminology in blog posts. Check this before using any technical chess term. If a term isn’t listed here, search for its definition before using it. Do NOT use a term unless you are confident it applies to the position being described.

Tactics

Fork: A single piece attacking two or more enemy pieces simultaneously. Any piece can fork. A pawn fork is when a pawn attacks two pieces diagonally.

Pin: A piece is pinned when it cannot move without exposing a more valuable piece behind it to attack. An absolute pin is against the king (the piece literally cannot move). A relative pin is against another piece (the piece can move but it would lose material).

Skewer: The reverse of a pin. A long-range piece attacks a valuable piece which, when it moves, exposes a less valuable piece behind it.

Discovered attack: Moving one piece to reveal an attack from a different piece behind it. The moved piece and the uncovered piece can both create threats simultaneously.

Discovered check: A discovered attack where the uncovered piece gives check.

Double check: A discovered check where both the moved piece and the uncovered piece give check simultaneously.

Deflection: Forcing an enemy piece away from a square it needs to defend.

Decoy: Luring an enemy piece to a square where it becomes vulnerable.

Zwischenzug (intermediate move): An unexpected move inserted before making an expected recapture or response.

Back rank mate: Checkmate delivered by a rook or queen on the opponent’s back rank (1st or 8th), where the king is trapped by its own pawns.

Positional Concepts

Outpost: A square that CANNOT be attacked by enemy pawns AND is ideally defended by one of your own pawns. Both conditions matter. A knight on e5 is not an outpost if the opponent still has an f-pawn that can challenge it. Before calling a square an outpost, verify: (1) no enemy pawn can attack it, (2) it is preferably supported by a friendly pawn.

Passed pawn: A pawn with no enemy pawns blocking or able to capture it on its path to promotion. No enemy pawns on the same file or adjacent files ahead of it.

Isolated pawn: A pawn with no friendly pawns on adjacent files. It cannot be defended by another pawn.

Doubled pawns: Two pawns of the same colour on the same file.

Backward pawn: A pawn that cannot advance because the square in front of it is controlled by an enemy pawn, and it has no friendly pawn on an adjacent file that could support its advance.

Pawn chain: A diagonal line of pawns defending each other. The base of the chain is the most vulnerable point.

Pawn break: A pawn move that challenges the opponent’s pawn structure, often opening lines or creating weaknesses.

Open file: A file with no pawns on it. Semi-open file has only one side’s pawns on it.

Battery: Two or more pieces of the same type (or queen + bishop/rook) lined up on a file, rank, or diagonal to combine their attacking power.

Fianchetto: Developing a bishop to g2 or b2 (for White) or g7 or b7 (for Black) after moving the knight’s pawn one square.

Blockade: Placing a piece (often a knight) directly in front of an enemy pawn to prevent it from advancing.

The exchange: The difference in value between a rook and a minor piece (bishop or knight). “Winning the exchange” means trading a minor piece for a rook. “Sacrificing the exchange” means giving up a rook for a minor piece.

Endgame Concepts

Opposition: When two kings face each other with one square between them. The player NOT to move has the opposition (an advantage), because they can maintain their position while the other king must give ground.

Zugzwang: A position where the player to move is at a disadvantage because any move they make worsens their position. More common in endgames.

Fortress: A defensive setup (usually in endgames) where the defending side can hold a draw despite being down material, because the opponent cannot make progress.

Stalemate: When a player has no legal moves but is not in check. The game is a draw.

General

Tempo: A unit of time measured in moves. Gaining a tempo means effectively getting an extra move, often by attacking a piece that must retreat. Losing a tempo means wasting a move.

Development: Getting pieces off their starting squares to active positions. A development advantage means having more pieces in play than your opponent.

Initiative: Having the ability to create threats and dictate the flow of the game, forcing the opponent to react.

Compensation: When a player who is down material has positional advantages (activity, initiative, attacking chances) that offset the material deficit.

Coordinate squares: Squares that are connected in a defensive relationship where pieces must maintain certain positions relative to each other.