Chess glossary

The king moves one square in any direction and may never move onto an attacked square.

The queen moves any number of unobstructed squares along a rank, file, or diagonal.

The rook moves any number of unobstructed squares along a rank or file.

The bishop moves any number of unobstructed squares along a diagonal.

The knight moves two squares in one direction and one square perpendicular to it.

A pawn moves straight forward, captures one square diagonally forward, and never moves backward.

A capture removes an opponent's piece when your piece legally moves to its square.

A king is in check when one or more opposing pieces attack its square.

Checkmate occurs when a king is in check and no legal move can remove the attack.

Stalemate is a draw in which the player to move has no legal move and the king is not in check.

Castling is one move that relocates the king two squares toward a rook and places that rook on the square the king crossed.

En passant lets a pawn capture an adjacent enemy pawn that has just advanced two squares as though it had moved only one.

A pawn that reaches the farthest rank must become a queen, rook, bishop, or knight of the same colour.

A draw ends the game without a winner, with each player receiving half a point in standard scoring.

A player may claim a draw when the same position occurs for at least the third time under the required conditions.

A player may claim a draw after each side has made 50 moves without a pawn move or capture.

A file is a vertical column labelled a through h, and a rank is a horizontal row numbered 1 through 8.

Algebraic notation records chess moves with piece letters, square names, and symbols for captures, checks, and special moves.

SAN is the standard compact notation used to record one legal chess move in its position.

PGN is a text format for storing a chess game, including moves and optional metadata or comments.

FEN is a one-line text description of a single chess position and its relevant game state.

An ECO code classifies opening positions with a letter from A to E and two digits.

Opening theory is the body of studied moves, positions, and plans known for the early phase of a chess game.

An opening repertoire is the set of prepared opening choices a player intends to use from one side of the board.

A variation is a recognized branch within an opening created by a particular move or sequence.

A main line is a central, well-established continuation used to organize an opening's theory.

A sideline is an alternative continuation outside the branch treated as the main line.

A gambit deliberately offers material, usually a pawn, in exchange for development, initiative, or another positional benefit.

Move order is the exact sequence used to reach an opening position.

A transposition occurs when different move orders reach the same chess position.

Development brings pieces from their starting squares to positions where they can take part in the game.

A tempo is one move's worth of time in a chess position.

The initiative is the ability to make threats that keep the opponent responding.

The center usually refers to the four squares d4, e4, d5, and e5, along with the surrounding central area.

Pawn structure is the arrangement of both sides' pawns and the open or closed lines they create.

A board cue is a visible feature of the current position that helps prompt the move or plan you learned.

Active recall means trying to produce an answer from memory before seeing it.

Spaced repetition distributes review across time instead of grouping every repetition into one session.

A review interval is the time between one review of an item and the next.