Chess terminology

The words used to describe squares, lines and written moves.

File

A column of eight squares from one player's side to the other, lettered a to h. See The board.

Rank

A row of eight squares, from left to right or right to left across the chessboard. They are numbered 1 to 8. See The board.

Diagonal

A slanting line of squares of one color, touching only at the corners.

Center

The four middle squares d4, d5, e4 and e5. Pieces are usually strongest here.

Extended center

The ring of squares around the center — c3, c4, c5, c6, d3, d6, e3, e6, f3, f4, f5 and f6. Controlling these squares supports a strong center.

Flank

The side of the board: the queenside (files a-c) or the kingside (files f-h).

Open file

A file with no pawns on it at all — ideal for rooks.

Half-open file

A file with only one pawn.

Algebraic notation

The standard way of writing moves: the piece letter plus the destination square, as in Nf3 or exd5.

Castling notation

0-0 means short (kingside) castling, 0-0-0 means long (queenside) castling. See Castling.

FEN

A single line of text that records one position, including whose turn it is and what castling is still allowed.

PGN

A text format that records a whole game: the players, the result and every move.

Touch-move

In official play, a piece you touch is a piece you must move, and a piece you release is a move you have made.

The basic vocabulary of legal play.

Legal move

A move the rules allow. A move that would leave your own king in check is never legal.

Capture

Taking an enemy piece by moving onto its square. You may never capture your own pieces.

Check

Your king is attacked and you must answer the attack at once. See Check and mate.

Checkmate

The king is in check and no legal move escapes it. The game ends immediately. See Check and mate.

Stalemate

The player to move is not in check but has no legal move. The game is a draw. See Draws.

Draw

A game that ends level, by stalemate, repetition, the fifty-move rule, insufficient material or agreement.

Resign

Giving up a lost game rather than playing it out.

Castling

The king steps two squares towards a rook and the rook hops to its other side. Only possible if neither piece has moved and the king is not in, through, or into check. See Castling.

En passant

A pawn that has just jumped two squares past an enemy pawn may be captured as if it had moved only one square, on that move only. See En passant.

Promotion

A pawn reaching the farthest rank becomes a queen, rook, bishop or knight. See Promotion.

Underpromotion

Choosing a rook, bishop or knight instead of a queen, usually to avoid stalemate or to deliver mate.

Threefold repetition

The same position with the same player to move occurs three times; either player may claim a draw.

Fifty-move rule

Fifty moves by each side with no capture and no pawn move is a draw.

Insufficient material

Neither side has enough left to force mate, for example king and bishop against king.

Short forcing ideas that win material or deliver mate.

Fork

One piece attacks two or more enemy pieces at the same time.

Pin

A piece cannot move without exposing something more valuable behind it.

Absolute pin

A pin against the king: the pinned piece is not allowed to move at all.

Relative pin

A pin against a valuable piece other than the king. Moving is legal but usually costly.

Skewer

Like a pin reversed: the valuable piece stands in front and must move, exposing the piece behind it.

Discovered attack

Moving one piece uncovers an attack from a piece standing behind it.

Double check

Two pieces check the king at once. Only a king move can answer it.

Double attack

Any move that creates two threats, so the opponent cannot meet both.

Battery

Two pieces lined up on the same file, rank or diagonal, adding their power together.

Sacrifice

Giving up material on purpose for attack, time or a mating net.

Zwischenzug

An in-between move: instead of the expected reply you insert a stronger threat first.

Desperado

A doomed piece that grabs as much material as it can before it falls.

Deflection

Forcing a defender away from the job it is doing.

Decoy

Luring a piece onto a square where it can be attacked or where it blocks its own side.

Interference

Cutting the line between a defender and the thing it defends.

Overloading

A piece is given more defensive duties than it can carry.

X-ray

A piece acting through another piece along the same line.

Windmill

A repeating sequence of check and discovered check that harvests material.

Trapped piece

A piece with no safe square, which can be won by attacking it again.

Counting

Checking how many attackers and defenders a square has before capturing on it.

Recognizable finishes worth learning by name.

Back-rank mate

A rook or queen mates on the last rank because the king's own pawns block its escape.

Smothered mate

A knight mates a king hemmed in entirely by its own pieces.

Scholar's mate

An early queen-and-bishop mate on f7 or f2, the classic beginner's trap.

Ladder mate

Two rooks (or rook and queen) drive the king to the edge rank by rank.

Anastasia's mate

Knight and rook trap the king against the edge of the board.

Boden's mate

Two bishops mate a castled king on crossing diagonals.

Damiano's mate

A queen mates a king whose shelter has been torn open by a pawn or rook sacrifice.

Legal's mate

A queen sacrifice followed by mate with knights and bishop against an early pin.

Opera mate

A rook mates on the back rank supported by a bishop on the long diagonal.

Mating net

A web of attacked squares from which the king cannot escape, even if mate is not yet forced.

Longer-term ideas about pieces, pawns and squares.

Development

Bringing your pieces off their starting squares into active play.

Tempo

A single unit of time. Gaining a tempo means making progress while your opponent must respond.

Initiative

Being the side making threats, so the opponent has to react.

Space

The number of squares your pawns and pieces control, especially in the opponent's half.

Weak square

A square you can no longer defend with a pawn.

Outpost

A square in enemy territory, protected by your pawn, where a knight sits safely.

Isolated pawn

A pawn with no friendly pawn on either neighboring file.

Doubled pawns

Two of your pawns on the same file.

Backward pawn

A pawn left behind its neighbors and unable to advance safely.

Passed pawn

A pawn with no enemy pawn in front of it or on the files beside it — a candidate to promote.

Pawn chain

A diagonal line of pawns defending one another.

Majority

More pawns than your opponent on one side of the board, often the source of a passed pawn.

Minority attack

Advancing your fewer pawns against the opponent's many to create weaknesses.

Good bishop

A bishop whose diagonals are not blocked by its own pawns.

Bad bishop

A bishop stuck behind its own pawns on the same color squares.

Bishop pair

Owning both bishops, a lasting advantage in open positions.

Fianchetto

Placing a bishop on g2, b2, g7 or b7 behind an advanced knight's pawn.

Prophylaxis

Preventing the opponent's plan before starting your own.

Zugzwang

Every legal move makes your position worse, yet you must move.

Fortress

A defensive setup the stronger side cannot break, even when material down.

Exchange

Trading pieces of similar value. 'The exchange' also means a rook for a bishop or knight.

Compensation

What you get back for material given up: activity, structure or attack.

How games are divided and how they are played in practice.

Opening

The first phase: developing pieces, claiming the center and getting the king safe.

Middlegame

The phase where plans, tactics and attacks decide the character of the game.

Endgame

The final phase, with few pieces left, where kings become active and pawns decide.

Book move

A move that is part of known, published opening theory.

Novelty

The first new move in a game, leaving known theory behind.

Blunder

A serious mistake that loses material or the game outright.

Mistake

An error that clearly worsens your position without losing at once.

Inaccuracy

A slightly imprecise move; the position stays roughly the same.

Time control

How much thinking time each player gets, and how it is added or reset.

Increment

Extra seconds added to your clock after each move.

Blitz

Fast chess, usually three to five minutes per player.

Rapid

Games of roughly ten to sixty minutes per player.

Classical

Long games, often over an hour per player, used in most major tournaments.

Flag

Running out of time. Losing on time is called being flagged.

Elo / rating

A number describing playing strength, which rises and falls with results.

FIDE

The International Chess Federation, which writes the official rules and awards titles.

Arbiter

The official who runs a tournament and applies the rules.

Swiss pairing

A tournament system pairing players on similar scores each round, without knockouts.

Bye

A round a player sits out, usually scored as a half or full point.