Board and rules
Pieces, squares, legal moves, results, and essential rules.
136 terms
Board and pieces
48- ChessboardA chessboard is a grid of 64 alternating squares arranged in eight ranks and eight files.Beginner
- SquareOne of the chessboard's 64 spaces, uniquely identified by a letter and a number.Beginner
- FileA vertical set of eight chessboard squares identified by one letter from a through h.Beginner
- RankA horizontal set of eight chessboard squares identified by one number from 1 through 8.Beginner
- DiagonalA slanting line of same-colored squares that changes one file and one rank at each step.Beginner
- CenterThe central area of the board, with d4, d5, e4, and e5 forming its core.Beginner
- Long diagonalOne of the two eight-square diagonals that cross the entire board from one corner to the opposite corner.Beginner
- PieceA movable chess unit; in the official rules, the word also includes pawns.Beginner
- KingThe piece that cannot be left under attack; if it is attacked and no permitted reply exists, the game ends.Beginner
- QueenA long-range piece that moves along ranks, files, and diagonals without jumping over other pieces.Beginner
- RookA long-range piece that moves any number of squares along ranks or files.Beginner
- BishopA long-range piece that moves diagonally and always remains on squares of one color.Beginner
- KnightA piece that jumps to a square two steps in one direction and one step perpendicular to it.Beginner
- PawnA piece that advances toward the opponent, captures diagonally, and can transform on the farthest rank.Beginner
- Minor pieceThe collective name for bishops and knights.Beginner
- Major pieceThe collective name for rooks and queens.Beginner
- Light-squared bishopA bishop that moves only among the board's thirty-two light squares.Beginner
- Dark-squared bishopA bishop that moves only among the board's thirty-two dark squares.Beginner
- Starting positionThe official arrangement of all thirty-two pieces before the first move.Beginner
- Back rankThe rank closest to a player, where that side's king, queen, rooks, bishops, and knights begin.Beginner
- First rankThe horizontal row numbered 1, located along White's side of the board.Beginner
- Seventh rankThe horizontal row numbered 7, where Black's pawns begin and a white pawn stands one rank from promotion.Beginner
- Promotion squareA square on the farthest rank that a pawn reaches and must use to become another piece.Beginner
- WhiteThe side with the light-colored pieces, which makes the first move of the game.Beginner
- BlackThe side with the dark-colored pieces, which replies after White's opening move.Beginner
- Light squareOne of the 32 squares that form the lighter half of the board's alternating pattern.Beginner
- Dark squareOne of the 32 squares that form the darker half of the board's alternating pattern.Beginner
- KingsideThe half of the board formed by the e-, f-, g-, and h-files, where the kings begin.Beginner
- QueensideThe half of the board formed by the a-, b-, c-, and d-files, where the queens begin.Beginner
- Chess setThe board and 32 pieces used to play, although some rules use “chess set” for the pieces alone.Beginner
- PositionThe game state at a particular moment, including pieces, side to move, and relevant special rights.Beginner
- Adapted chessboardA board designed so that the position and pieces can be identified and handled mainly through touch.Intermediate
- Adjacent squareA square that shares an edge or a corner with another square on the board.Beginner
- Bare kingA situation in which one side has only its king left, with no pawns or other pieces.Basic
- Bishop pawnA pawn on a bishop file, meaning the c-file or the f-file.Basic
- Chessboard orientationThe correct placement of the board, with a light square at each player's near right corner.Beginner
- Demonstration boardA large board that reproduces a position so a group can see it easily.Basic
- Electronic chessboardA physical board that detects pieces and moves so they can be recorded, stored, or transmitted to other systems.Intermediate
- FlankAn outer board region formed by the a-, b-, and c-files or by the f-, g-, and h-files.Basic
- King's pawnA pawn on the e-file, called the king's file because the king starts there.Beginner
- Knight pawnA pawn on a knight file, meaning the b-file or the g-file.Basic
- Promoted pieceA queen, rook, bishop, or knight that replaces a pawn when it reaches the last rank.Basic
- Promotion rankThe rank farthest from a pawn's starting side, where that pawn must become another piece.Beginner
- Queen's pawnA pawn on the d-file, called the queen's file because the queen starts there.Beginner
- Rook pawnA pawn on a rook file, meaning the a-file or h-file at the edge of the board.Basic
- Sliding pieceA bishop, rook, or queen that can travel any number of squares along an allowed clear line.Intermediate
- Starting squareThe square a piece occupies at the beginning of a game with the standard setup.Basic
- Staunton chess setA recognizable chess-piece design used as the practical standard for modern competitive play.
Rules and legal moves
66- Legal moveA move that follows every applicable rule and does not leave the player's own king in check.Beginner
- Illegal moveA move that breaks a rule, especially one that leaves or places the player's own king in check.Beginner
- Touch-move ruleAn in-person rule requiring a deliberately touched piece to be moved or captured when a legal option exists.Beginner
- j'adoubeA phrase spoken before touching a piece to show that it will only be adjusted within its square.Beginner
- CheckA position in which the king is attacked and must be made safe on the immediate move.Beginner
- CheckmateA check with no legal defense, ending the game immediately in victory for the attacking player.Beginner
- StalemateA drawn position where the player to move is not in check but has no legal move.Beginner
- CaptureA move that removes an opposing piece by occupying its square, except for the special en passant capture.Beginner
- RecaptureA capture answering an opponent's capture, usually by immediately taking the piece that just captured.Beginner
- CastlingA special move in which the king moves two squares toward a rook and that rook crosses to the king's other side.Beginner
- Kingside castlingCastling toward the kingside rook, leaving the king on g1 or g8 and the rook on f1 or f8.Beginner
- Queenside castlingCastling toward the queenside rook, leaving the king on c1 or c8 and the rook on d1 or d8.Beginner
- en passantA special pawn capture that immediately takes a pawn just advanced two squares as though it had advanced one.Beginner
- PromotionPromotion replaces a pawn that reaches the last row with a queen, rook, bishop, or knight of the same color.Beginner
- UnderpromotionUnderpromotion means promoting a pawn to a rook, bishop, or knight instead of choosing a queen.Beginner
- InterpositionInterposition stops a rook, bishop, or queen check by placing another piece between the attacker and the king.Basic
- Discovered checkA discovered check occurs when one piece moves away and uncovers another piece's attack on the king.Basic
- Double checkDouble check occurs when one move leaves the king attacked by two pieces at the same time.Basic
- Perpetual checkPerpetual check is a forced sequence of repeated attacks on the king that can return to the same cycle again and again.Basic
- Draw offerA draw offer proposes ending the game without a winner and has that effect only if the opponent accepts.Basic
- ResignationResignation is a voluntary declaration that a player will not continue, normally ending the game in an immediate loss.Basic
- Flag-fallFlag-fall is the signal that a player's allotted time on the chess clock has expired.Basic
- TimeoutTimeout means a player failed to complete the required moves before their chess clock reached zero.Basic
- ForfeitA forfeit is a game loss imposed for absence, a rule violation, or failure to meet a competition condition.Basic
- Threefold repetitionThreefold repetition allows a draw claim when the same position appears for the third time with the same legal possibilities.Intermediate
- Fivefold repetitionThe game is automatically drawn when the same position appears at least five times, with no claim required.Intermediate
- Fifty-move ruleA player may claim a draw after 50 moves by each side without a pawn move or a capture.Intermediate
- Seventy-five-move ruleThe game is automatically drawn after 75 moves by each player without a pawn move or capture, unless the last move checkmates.Intermediate
- Dead positionA position in which neither player can deliver checkmate through any possible sequence of legal moves.Intermediate
- Insufficient materialA common term for pieces that cannot produce checkmate, judged by legal mating possibility rather than material value alone.Intermediate
- MoveA legal action taken by one player on their turn to change the position on the board.Beginner
- Chess clockA device with two connected time displays that separately measures each player's available thinking time.Beginner
- AttackA piece attacks a square or opposing piece when it could capture there according to its movement pattern.Beginner
- Attacked squareA square controlled by an opposing piece because that piece could capture there under its movement rules.Basic
- Castling rightsA position state showing whether a player still retains the legal right to castle with each rook.Intermediate
- Check evasionA legal move that removes the immediate attack on the player’s own king.Basic
- Clock flagThe indicator on each side of a chess clock showing that a player’s allotted time has expired.Basic
- Completed moveA move that has reached its final rules state, usually after the board move is made and the clock is pressed.Intermediate
- Digital chess clockAn electronic two-display clock that controls playing time and supports programmable modes such as increment and delay.Basic
- Displaced pieceA piece accidentally moved away from its correct place without necessarily constituting a chess move.Basic
- Double pawn pushA pawn’s optional first move of two squares, legal only when both squares ahead are empty.Beginner
- En passant rightA temporary chance to capture an enemy pawn immediately after its initial two-square advance.Intermediate
- Illegal positionA board state that could not have been reached through any sequence of legal moves.Intermediate
- Illegal-move penaltyThe rules consequence applied when a player completes a move that does not meet the legal requirements.Intermediate
- Intended moveThe exact move formally declared before play to support certain draw claims under the rules.Intermediate
- IrregularityA competition situation that departs from the correct state or procedure and requires a rules response.Intermediate
- Irreversible moveA move that permanently changes a piece, right, or historically significant part of the position state.Advanced
- Made moveA move whose physical execution has become fixed under the rules, before any separate completion by the clock.Intermediate
- Mating materialThe pieces and position circumstances that allow some checkmate to be reached through legal moves.Intermediate
- Mechanical chess clockA non-electronic chess clock with two linked mechanisms and a physical flag indicating the end of a time period.Basic
- Move-counterA clock device that records how many times each player has pressed their clock control.Intermediate
- One-hand ruleThe requirement to execute each move with one hand and press the clock with that same hand.Basic
- Origin squareThe square occupied by a piece immediately before it begins a move.Basic
- Position reinstatementThe procedure for reconstructing an earlier position and resuming the game from it after an irregularity.Advanced
- Press the clockTo operate the button or lever that stops your time and starts your opponent's time.Beginner
- Pseudo-legal moveA candidate move that follows basic piece movement but may still be illegal because it leaves the moving side's king in check.Advanced
- QueeningPromotion in which a pawn reaching the farthest row is replaced by a new queen of the same color.Basic
- Reversed colorsAn irregularity in which the players begin with the opposite colors from those assigned to them.Intermediate
- Reversible moveIn technical analysis, a non-pawn move to an empty square that does not reset the fifty-move count.Advanced
- Same positionA rules-based identity between positions with the same pieces, side to move, and possible moves.Advanced
- Self-checkAn illegal result created by moving so that the moving side's king remains or becomes attacked.Basic
- Side to moveThe player, White or Black, who has the right and obligation to make the next move.Beginner
- Talking chess clockAn accessible chessclock that speaks the time and, depending on the model, the move count.Intermediate
- Target squareThe square occupied by the moving piece when a move has been made.Basic
- Time displayEither of the two parts of a chessclock that shows one player's remaining time.Basic
- Two-handed moveThe physical execution of one move with both hands, contrary to the competitive one-hand requirement.Intermediate
Results and claims
22- WinA final result in which one player wins the game and the other receives a loss.Basic
- LossA final result in which one player loses the game and the opponent receives the win.Basic
- DrawA final result in which the game ends without either player winning.Basic
- Draw by agreementThe game ends as a draw when one player offers that result and the other accepts.Basic
- Forfeit winA result awarded because the opponent loses under tournament rules rather than through the normal outcome of a played game.Basic
- Forfeit lossA loss imposed by a competition rule or arbiter's ruling even when the board position was not lost.Basic
- WalkoverA win awarded without starting the game because the assigned opponent does not appear or cannot play.Basic
- No-showA player's absence from a round in which an opponent had been assigned, especially when the player misses the permitted arrival deadline.Basic
- Default timeThe maximum permitted delay after a round starts before a player normally loses for failing to appear.Basic
- Automatic drawA draw that arises when a rules condition is met without either player having to claim it.Intermediate
- ClaimA rules-based request by which a player invokes a right that the arbiter must verify.Basic
- Claimable drawA draw that ends the game only after a correct claim by the player having the move.Intermediate
- Double forfeitAn exceptional result in which both players receive a loss because of an infringement or administrative ruling.Intermediate
- Draw claimA formal request for the arbiter to declare a draw because a rule-based condition has been met.Intermediate
- Draw on timeA draw when a player's time expires but the opponent cannot checkmate through any legal sequence of moves.Intermediate
- Game pointThe scoring unit awarded to a player for the result of one game.Beginner
- Game resultThe formal record of how a game ended for each player.Beginner
- Insufficient losing chancesAn optional US Chess procedure for claiming a draw in certain time scrambles with very little practical chance of losing.Advanced
- Simultaneous flag-fallA situation in which both clocks show expired time and the order of the two flag-falls cannot be established.Advanced
- Tablebase claimA specialized ICCF request to set the result of an ending exactly resolved by a database covering up to seven pieces.Expert
- Unfinished gameA game that started but whose final result is not yet known or available.Basic
- Unplayed gameA scheduled or recorded pairing in which the two players did not contest valid moves against each other.Intermediate