This page explains commonly used terms in chess in alphabetical order. Some of these have their own pages, like fork and pin. For a list of unorthodox chess pieces, see fairy chess piece; for a list of terms specific to chess problems, see chess problem terminology; for a list of chess related games, see chess variants.

Absolute pin

A pin against the king, called absolute because the pinned piece cannot legally move as it would expose the king to check. See relative pin.

Active

Describes a piece that is able to move or control many squares. See also passive.

Adjournment

Envelope used for the adjournment of a match game Efim Geller vs. Bent Larsen, Copenhagen 1966

Suspension of a chess game with the intention to continue at a later occasion. See Sealed move.

Adjudication

The process of a strong chess player deciding on the outcome of an unfinished game. This practice is now uncommon in over the board events, but does happen in online chess when one player refuses to continue after an adjournment.

Adjust or j'adoube

To adjust the position of a piece on its square without being required to move it. Adjustment can only be done when it is the player's move and the adjustment is preceded by saying "I adjust" or "j'adoube".

Advanced pawn

A pawn that is on the opponent's side of the board (the fifth rank or higher). An advanced pawn may be weak if it is overextended, lacking support and difficult to defend, or strong if it cramps the enemy by limiting his mobility. An advanced passed pawn that threatens to promote can be especially strong.

Alekhine's gun

A formation in which a queen backs up two rooks on the same file.

Algebraic notation

The standard way to record a chess game using alphanumeric codes for the squares.

Amateur

A person who does not earn a living through chess. The distinction between professional and amateur is not very important in chess as amateurs may win prizes, accept appearance fees, and earn any title including World Champion. In the 19th century, "Amateur" was sometimes used in published game scores to conceal the name of the losing player in a Master vs. Amateur contest. It was thought to be impolite to use a player's name without permission, and the professional did not want to risk losing a customer. See also NN or N.N.

Analysis

Study of a position to determine best play for both sides.

Annotation

Commentary on a game using a combination of written comments, chess symbols or notation.

Antipositional

A move or a plan that is not in accordance with the principles of positional play. Antipositional is used to describe moves that are part of an incorrect plan rather than a mistake made when trying to follow a correct plan. Antipositional moves are often pawn moves, since pawns cannot move backwards to return to squares they have left.

Anti-Sicilians

Variations that White uses against the Sicilian Defense (1.e4 c5) other than the most common plan of 2.Nf3 followed by 3.d4 cxd4 4.Nxd4 (the Open Sicilian). Some Anti-Sicilians include the Alapin Variation (2.c3), Moscow Variation (2.Nf3 d6 3.Bb5+), Rossolimo Variation (2.Nf3 Nc6 3.Bb5), Grand Prix Attack (2.Nc3 Nc6 3.f4 g6 4.Nf3 Bg7 and now 5.Bc4 or 5.Bb5), Closed Sicilian (2.Nc3 followed by g3 and Bg2), Smith-Morra Gambit (2.d4 cxd4 3.c3), and Wing Gambit (2.b4).

Arbiter

See International Arbiter.

Armageddon

A game which White must win to win the match, but which Black only needs to draw to win the match. White has more time than black: the discrepancy can vary, but in FIDE World Championships, White has six minutes, while Black only has five. Typically used in playoff tie-breakers where shorter blitz games have not resolved the tie.

Artificial castling

Refers to a maneuver of several single moves by the king and a rook where they end up as if they had castled.

Attack

An assault, either short-term (e.g., after 1.e4 Nf6, Black is attacking White's pawn on e4) or long-term, for example in the form of a sustained mating attack against the enemy king or a minority attack against the opponent's queenside pawn structure. See defence.

Automaton

A self-operating chess-playing machine. Popular attractions in the 18th and 19th centuries, most of these devices were hoaxes under the control of a human player. The most famous chess-playing automaton was The Turk.

Symbol used for the bishop when recording chess moves in English.

Back rank

A player's first rank (the one on which the pieces stand in the initial array); White's back rank is Black's eighth rank and vice versa.

Back rank mate

A checkmate delivered by a rook or queen along a back rank in which the mated king is unable to move up the board because the king is blocked by friendly pieces (usually pawns) on the second rank.

Backward pawn

A pawn that is behind the pawns of the same color on the adjacent files and that cannot be advanced with the support of another pawn.

Bad bishop

A bishop which is hemmed in by the player's own pawns.

Battery

An arrangement of two pieces in line with the enemy king on a rank, file, or diagonal so that if the middle piece moves a discovered check will be delivered. The term is also used in cases where moving the middle piece will uncover a threat along the opened line other than a check.

BCF

British Chess Federation, the former name of the English Chess Federation. See ECF.

BCM

An abbreviation for the British Chess Magazine.

BCO

An abbreviation sometimes used for the chess opening reference Batsford's Chess Openings. The second edition is often called BCO-2. Cf. ECO and MCO.

Bind

A strong grip or stranglehold on a position that is difficult for the opponent to break. A bind is usually an advantage in space created by advanced pawns. The Maróczy Bind is a well-known example. See also Squeeze.

Bishop

see bishop

Bishops on opposite colors

A situation in which one side has only its light-squared bishop remaining while the other has only its dark-squared bishop remaining. In endgames, this often results in a draw if there are no other pieces (only pawns), even if one side has one or two pawns extra, since the bishops control different squares (see opposite colored bishops endgame). In the middlegame, however, the presence of opposite colored bishops imbalances the game and can lead to mating attacks, since each bishop attacks squares that cannot be covered by the other.

Bishop pair

In open positions, two bishops (on opposite colors) are considered to have an advantage over two knights or a knight and a bishop. (In closed positions knights may be more valuable than bishops.) The player with two bishops is said to have the bishop pair.

Bishop pawn

A pawn on the bishop's file, i.e. the c-file or f-file.

Black

The designation for the player who moves second, even though the corresponding pieces, referred to as "the black pieces," are sometimes actually some other (usually dark) color. Similarly, the dark-colored squares on the chessboard are often referred to as "the black squares" even though they often are not literally black. See also White, First-move advantage in chess.

Blindfold chess

A form of chess in which one or both players are not allowed to see the board.

Blitz chess

A fast form of chess (Blitz being German for lightning) with a very short time limit, usually 3 or 5 minutes per player for the entire game. With the advent of electronic chess clocks, it is often the case that the time remaining is incremented by 1 or 2 seconds per move.

Blockade

A strategic placement of a minor piece directly in front of an enemy pawn, where it restrains the pawn's advance and gains shelter from attack. Blockading pieces are often overprotected.

Blunder

A very bad move, an oversight (indicated by "??" in notation).

Board

See chessboard.

Book draw

An endgame position known to be a draw with perfect play. The name reflects that traditionally the analysis has been found in the chess endgame literature, but in simplified positions (currently six pieces or fewer) computer analysis in an endgame tablebase can be used.

Book move

An opening move found in the standard reference books on opening theory. A game is said to be "in book" when both players are playing moves found in the opening references. A game is said to be "out of book" when the players have reached the end of the variations analyzed in the opening books or if one of the players deviates with a novelty (or a blunder).

Book win

An endgame position known to be a win with perfect play. The name reflects that traditionally the analysis has been found in the chess endgame literature, but in simplified positions (currently six pieces or fewer) computer analysis in an endgame tablebase can be used.

Break

A pawn advance or capture that opens up a blocked position.

Breakthrough

Destruction of a seemingly strong defense, often by means of a sacrifice.

Brevity

(chiefly British) See Miniature.

Brilliancy

A spectacular and beautiful game of chess, generally featuring sacrificial attacks and unexpected moves. Brilliancies are not always required to feature sound play or the best moves by either side.

Brilliancy prize

A prize awarded at some tournaments for the best brilliancy played in the tournament.

Bronstein delay

A time control method with time delay, invented by David Bronstein. When it becomes a player's turn to move, the clock waits for the delay period before starting to subtract from the player's remaining time.

Bughouse chess

A chess variant played with teams of two or more.

Bullet chess

A form of chess in which each side has 1 minute to make all their moves.

Bye

A tournament round in which a player does not have a game, usually because there are an odd number of players. A bye is normally scored as a win (1 point), although in some tournaments a player is permitted to choose to take a bye (usually in the first or last round) and score it as a draw (˝ point).

Caďssa

The goddess of chess, occasionally invoked to indicate luck or good fortune: "Caissa was with me".

Calculate

To carefully plan a series of moves while considering possible responses.

Candidate move

A move that seems good upon initial observation of the position, and that warrants further analysis.

Candidates Match

A knockout match in the Candidates Tournament.

Candidates Tournament

A tournament organised by the FIDE, the third and last qualifying cycle of the World Chess Championship. The participants are the top players of the interzonal tournament plus possibly other players selected on the basis of rating or performance in the previous candidates tournament. The top ranking player(s) qualify(ies) for the world championship.

Capped piece

A certain piece with which one player tries to deliver checkmate. When the capped piece is a pawn, it is called a pion coiffé (French for capped pawn). Playing with a capped piece is a handicap in chess.

Capture

Remove the opponent's piece or pawn from the board by taking it with one's own piece or pawn. Except in the case of an en passant capture, the capturing piece or pawn does so by occupying the same square that the captured piece or pawn occupied.

Castling

A special move involving both the king and one rook. Its purpose is generally to protect the king and develop the rook. Castling on the kingside is sometimes called castling short and castling on the queenside is called castling long; the difference is based on whether the rook moves a short distance (two squares) or a long distance (three squares).

Casual game

See friendly game.

Category tournament

The category of a tournament is a measure of its strength based on the average FIDE rating of the participants. The category is calculated by rounding up the number (average rating ? 2250)/25. So each category covers a 25 point rating range, starting with Category 1 which spans ratings between 2251 and 2275. A Category 18 tournament has an average rating between 2676 and 2700.

CC

An abbreviation sometimes used for correspondence chess.

Centralization

Moving a piece or pieces toward the center of the board. In general, pieces are best placed in or near the center of the board because they control a large number of squares and are available for play on either flank as needed. Because of their limited mobility, knights in particular benefit from being centralized. There are several chess aphorisms referring to this principle: "A knight on the rim is dim" (or "grim" instead of "dim") and "A knight on the side cannot abide."

Centre/Center

The four squares in the middle of the board.

Central pawn

A pawn on the king's file or queen's file, i.e. on the d-file or e-file.

Cheapo

Slang for a primitive trap, often set in the hope of swindling a win or a draw from a lost position.

Check

An attack on the king. The attacked king is said to be in check.

Checkmate

A position in which a player's king is in check and the player has no legal move (i.e cannot move out of check). A player whose king is checkmated loses the game.

Chessboard

This is the chequered board used in chess. It consists of 64 squares (eight rows and eight columns) arranged in two alternating colors (light and dark). Similar boards are also known as checkerboards.

A chess clock

Chess clock

A device made up of two adjacent clocks and buttons, keeping track of the total time each player takes for his or her moves.

Classical

An opening system geared towards forming a full pawn center. See also Hypermodern.

Clock move

A timed game is played clock move if a move is completed only when the clock has been pressed. It is therefore possible to touch one piece, but then decide to move another piece. This way of playing is common in casual games, in favour of touch move.

Closed game

• A position with few open lines (files or diagonals), generally characterized by interlocking pawn chains, cramped positions with few opportunities to exchange, and extensive maneuvering behind lines. Such a position may later become an Open game. See also Positional game.

• A chess opening that begins with the moves 1.d4 d5. See also Open game and Semi-open game.

Closed file

A file on which black and white both have a pawn.

Closed tournament

A tournament in which only invited or qualifying players may participate, as opposed to an open tournament. Also called an invitational tournament.

Coffeehouse

Adjective used to describe a move, player, or style of play characterized by risky, positionally dubious play that sets traps for the opponent. The name comes from the notion that one would expect to see such play in skittles games played in a coffeehouse or similar setting, particularly in games played for stakes and/or blitz chess. The Blackburne Shilling Gambit is a typical example of coffeehouse play.

Color

The white or black pieces.

Combination

A clever sequence of moves, often involving a sacrifice, to gain the advantage. The moves of the other player are usually forced, i.e. a combination does not give the opponent too many possible lines of continuation.

Compensation

An imbalanced equivalent return, for example sacrificing material for development or trading a bishop for three pawns.

Connected pawns

Refers to two or more pawns of the same color on adjacent files. See also isolated pawns.

Connected passed pawns

Passed pawns on adjacent files. These are considered to be unusually powerful (often worth a minor piece or rook if on the sixth rank or above and not properly blockaded) because they can advance together. Also see connected pawns.

Connected rooks

Two rooks of the same color on the same rank or file with no pawns or pieces between them. Connected rooks are usually desirable. Players often connect rooks on their own first rank or along an open file. cf. Doubled rooks.

Control of the centre/center

Having one or more pieces that attack any of the four centre squares; an important strategy, and one of the main aims of openings.

Cook

An unintended solution of a chess problem. The term may also be used more generally to refer to a refutation to published analysis.

Correspondence chess

This is chess played at a long time control by various forms of long-distance correspondence, usually through a correspondence chess server, through email or by the postal system. Typically, one move is transmitted in every correspondence.

Corresponding squares

Squares of reciprocal (or mutual) Zugzwang often found in king and pawn endgames. Also known as related squares.

Counterattack

An attack that responds to an attack by the other player.

Countergambit

A gambit offered by Black, for example the Greco Counter Gambit, usually called the Latvian Gambit today (1.e4 e5 2.Nf3 f5?!); the Albin Countergambit (1.d4 d5 2.c4 e5); and the Falkbeer Countergambit (1.e4 e5 2.f4 d5). An opening need not have "countergambit" in its name to be one; for instance, the Benko Gambit (1.d4 Nf6 2.c4 c5 3.d5 b5), Englund Gambit (1.d4 e5?), the Budapest Gambit (1.d4 Nf6 2.c4 e5), the Blackburne Shilling Gambit (1.e4 e5 2.Nf3 Nc6 3.Bc4 Nd4?!) and many lines of the Two Knights Defense (e.g. 1.e4 e5 2.Nf3 Nc6 3.Bc4 Nf6 4.Ng5 and now 4...Bc5!? (the Wilkes-Barre Variation or Traxler Counter-Attack), 4...Nxe4?!, 4...d5 5.exd5 Na5 6.Bb5+ c6 (the main line), 4...d5 5.exd5 Nd4 (the Fritz Variation), and 4...d5 5.exd5 b5 (the Ulvestad Variation)) are all examples of countergambits.

Counterplay

Active maneuvering by the player in an inferior or defensive position.

Cover

To protect a piece or control a square. For example, to checkmate a king on the side of the board, the five squares adjacent to the king must all be covered.

Cramped

A position with limited mobility.

Critical position

A position that is of key importance in determining the soundness of an opening variation. If one side can demonstrate an advantage in a critical position, the other side must either find an improvement or else abandon that variation as inferior.

Cross-check

A cross-check is a check played in reply to a check, especially when the original check is blocked by a piece which itself either delivers check or reveals a discovered check from another piece.

Crosstable

An arrangement of the results of every game in a tournament in tabular form. The names of the players run down the left side of the table in numbered rows. The names may be listed in order of results, alphabetically, or in pairing order, but results order is most common. The columns are also numbered, each one corresponding to the player in the same numbered row. Each table cell records the outcome of the game between the players on the intersecting row and column, using 1 for a win, 0 for a loss, and ˝ for a draw. (In a double round-robin tournament each cell contains two entries, as each pair of players plays two games alternating white and black.) Every game is recorded twice, once from the perspective of each player. The diagonal cells that correspond to the player playing himself are marked with a * or other symbol as they are not used. For examples see Hastings 1895 chess tournament, Nottingham 1936 chess tournament, and AVRO tournament.

Dark squares

The 32 dark-coloured squares on the chessboard, such as a1 and h8. A dark square is always located at a player's left hand corner.

Dark-square bishop

One of the two bishops that moves on the dark squares, situated in c1 and f8 in the initial position.

Dead draw

A drawn position in which neither player has any realistic chance to win. A dead draw may refer to a position in which it is impossible for either player to win (such as insufficient material), or it may refer to a simple, lifeless position which would require a major blunder before either side would have a chance to win.

Decoy

This is a chess tactic used to lure a piece to an unfavourable square.

Defence

(1) A move or plan which tries to meet the opponent's attack; (2) an opening played by Black, for example the Scandinavian Defence, King's Indian Defense, English Defense, etc.

Deflect

To cause a piece to move to a less suitable square. Typically used in the context of a combination or attack, where the deflected piece is critical to the defence.

Wouter Mees at the demonstration board

Demonstration board

A large standing chess board used to analyse a game or show a game in progress. Johann Löwenthal invented the demonstration board in 1857.

Descriptive notation

An old system of recording chess moves, used primarily in the English and Spanish speaking countries through the 1970s or 1980s. Now replaced by the standard algebraic notation.

Desperado

• A piece that seems determined to give itself up, typically either to bring about stalemate

• A piece to sell itself as dearly as possible in a situation where both sides have hanging pieces.

Develop

In the opening, moving a piece from its original square to make it more active. To redevelop a piece means to move it to a better square after it has already been developed.

Diagonal

A line of squares of the same colour, along which a queen or bishop can move.

Discovered attack

An attack made by a queen, rook or bishop when another piece or pawn moves out of its way.

Discovered check

A check delivered by a piece when another piece or pawn has moved out of its way.

Domination

A situation whereby capture of a piece is unavoidable despite it having wide freedom of movement. Usually occurs in chess problems.

Double attack

Two attacks made with one move: these attacks may be made by the same piece (in which case it is a fork); or by different pieces (a situation which may arise via a discovered attack in which the moved piece also makes a threat). The attacks may directly threaten opposing pieces, or may be threats of another kind: for instance, to capture the queen and deliver checkmate.

Double check

A check delivered by two pieces at the same time. A double check necessarily involves a discovered check.

Doubled pawns

A pair of pawns of the same color on the same file.

Doubled rooks

Two of a player's rooks placed on the same file or rank.

Draw

A game that ends without victory for either player. Most drawn games are draws by agreement. The other ways that a game can end in a draw are stalemate, threefold repetition, the fifty move rule, and insufficient material. A position is said to be a draw (or a drawn position) if either player can, through correct play, eventually force the game into a position where the game must end in a draw, regardless of the moves made by the other player. A draw is usually scored as ˝ point, although in some matches only wins are counted and draws are ignored.

Drawing line

An opening variation that commonly ends in a draw, for example 1.e4 e5 2.Nf3 Nc6 3.Nc6 Nf6 4.Bb5 Nd4 5.Nxd4 exd4 6.e5 dxc3 7.exf6 Qxf6 8.dxc3 Qe5+ 9.Qe2 Qxe2+, a line in the Rubinstein Variation of the Four Knights Game. See Collection of drawing lines at chessgames.com. Often such a variation is played because one or both players is/are eager to draw the game.

Drawing weapon

An opening line that a player plays with the intent of drawing the game. This may or may not be a line commonly thought of as a drawing line. In high-level chess and correspondence chess, a player well-versed in opening theory may even use as a drawing weapon a sharp opening that has been analyzed to a drawn position in a number of lines, such as the Marshall Attack in the Ruy Lopez, and the Sveshnikov and Poisoned Pawn variations of the Sicilian Defense. One example of the successful employment of a drawing weapon was the 2000 World Chess Championship match between Garry Kasparov and Vladimir Kramnik. In that match, Kramnik used the Berlin Defense to the Ruy Lopez as a drawing weapon with great effect. Kramnik drew all four games with that opening, drew all the rest of his games as Black, and won two games as White, with no losses.

Duffer

A weak chess player, also referred to as a "fish", "patzer" or "woodpusher."

Dynamism

A style of play in which the activity of the pieces is favoured over more positional considerations, even to the point of accepting permanent structural or spatial weaknesses. Dynamism stemmed from the teachings of the 'Hypermodern movement' and challenged the dogma found in more classical teachings, such as those put forward by Wilhelm Steinitz and Siegbert Tarrasch.

ECF

The English Chess Federation (ECF) is the governing chess organisation in England and is one of the federations of the FIDE. It was known as British Chess Federation(BCF) until 2005 when it was renamed.

ECO

The Encyclopaedia of Chess Openings, a standard and comprehensive chess opening reference. Also a classification system (ECO code) for chess openings that assigns an alphanumeric code from A00 to E99 to each opening.

Elo rating system

The Elo rating system is a method for calculating the relative skill levels of chess players, named after the Hungarian Arpad Elo. Since 1970 FIDE publishes quarterly an international chess rating list using the Elo system.

En passant

("in the act of passing"; derived from French) The rule that allows a pawn that has just advanced two squares to be captured by a pawn on the same rank and adjacent file. The pawn is therefore taken as if it had only moved one space. It is only possible to take en passant on the next move.

En prise

(from French) A piece that can be captured. Usually used of a piece that is undefended and can be captured.

Endgame

The stage of the game when there are few pieces left on the board. The endgame follows the middlegame.

Endgame tablebase

A computerized database of endgames with up to seven pieces, providing perfect play for both players, and thus completely solving those endgames. (The six-piece endgames have been finished; some seven-piece endgames have been finished as of 2008.)

Epaulette mate

A checkmate position where the king is blocked on both sides by his own rooks.

Extended Position Description (EPD)

A Forsyth-Edwards Notation derivative format that contains the position on the chessboard, but not the game. It is primarily used to test chess engines.

Equalise/Equalize

To create a position where the players have equal chances of winning (referred to as "equality"). In opening theory, since White has the advantage of the first move, lines that equalize are relatively good for Black and bad for White.

Escape square

A square to which a piece can move, which allows it to escape attack. See also flight square and luft.

Exchange

• The capture of a pair of pieces, one white and the other black, usually of the same type (i.e rook for rook, knight for knight etc).

• The exchange is used to refer to the advantage of a rook over a minor piece (knight or bishop). The player who captures a rook while losing a minor piece is said to have won the exchange, and the opponent is said to have lost the exchange. An exchange sacrifice is giving up a rook for a minor piece.

Exchange variation

This is a type of opening in which there is an early, voluntary exchange of pawns or pieces.

Exhibition

A contest of one or more games played for the purpose of public entertainment, as opposed to a match or tournament. An exhibition may pit two masters against each other, in which case chess clocks are normally used and the contest is quite serious. A simultaneous exhibition (or display) has one or more masters play many celebrity or amateur opponents at once, and is often not timed.

Expanded centre

The central sixteen squares on the board.

Family fork, family check

A knight fork that attacks more than two opposing pieces concomitantly.

Fast chess

A form of chess in which both sides are given less time to make their moves than under the normal tournament time controls. See also blitz chess.

Fianchetto

Refers to a bishop developed to the second square on the file of the adjacent knight (that is, b2 or g2 for white, b7 or g7 for black), or the process of developing a bishop to such a square. It usually occurs after moving the pawn on that file ahead one square (or perhaps two). The Italian word is actually a noun ("in fianchetto") and not a verb.

FIDE

The World Chess Federation (Fédération Internationale des Échecs), the primary international chess organizing and governing body. The abbreviated name FIDE is nearly always used in place of the full name in French.

First-move advantage

The slight (by most accounts) advantage that White has by virtue of moving first.

FEN

Abbreviation for Forsyth-Edwards Notation, which is a standard notation for describing a particular board position of a chess game. The purpose of FEN notation is to provide all the necessary information to restart a game from a particular position.

FIDE Master (FM)

A chess title ranking below International Master.

File

A column of the chessboard. A specific file can be named either using its position in algebraic notation, a?h, or by using its position in descriptive notation. For example, the f-file or the king bishop file comprises the squares f1?f8 or KB1?KB8.

Fifty move rule

A draw may be claimed if no capture or pawn move has occurred in the last fifty moves by either side.

First board

See top board.

Fish

A weak chess player, also referred to as a "duffer", "patzer" or "woodpusher".

Fischer delay

A time control method with time delay, invented by Robert Fischer. When it becomes a player's turn to move, the delay is added to the player's remaining time.

Flight square

A square to which a piece can move, which allows it to escape attack. See also escape square and luft.

Flag

Part of an analogue chess clock (usually red) which indicates when the minute hand passes the hour. To flag someone means winning the game on the basis of the opponent exceeding the time control.

Flank

The queenside a, b, and c-files, or the kingside f, g, and h-files, also called wing; distinguished from the center d and e-files.

Flank opening

This a chess opening played by White and typified by play on one or both flanks.

FM

Abbreviation for the FIDE Master title.

Focal point

The square upon which a player focuses an attack, e.g. by repeatedly attacking that square or sacrificing a piece there. For example, in an attack upon an uncastled king, Black's f7 square (or White's f2 square) is a common focal point. Examples of attacks on the focal point f7 include the Fried Liver Attack (initiated by a knight sacrifice on f7) and the primitive Scholar's Mate (ending with checkmate on f7).

Fool's mate

The shortest possible chess game ending in mate: 1. f3 e5 2. g4 Qh4# (or minor variations on this).

Forced move

A move which is the only one which does not result in a serious disadvantage for the moving player.

Forfeit

Refers to losing the game by absence or by exceeding the time control (forfeit on time).

Fork

When one piece, generally a knight or pawn, simultaneously attacks two (or more) of the opponent's pieces, often specifically called a knight fork when the attacker is a knight. Some sources state that only a knight can give a fork and that the term double attack is correct when another piece is involved, but this is by no means a universal usage.

Fortress

A fortress is a position that, if obtained by the weaker side, will prevent the opposing side from penetration, this generally resulting in a draw (which the weaker side is seeking).

Friendly game

A game that is not played as part of a match, tournament, or exhibition. Often the game is not timed, but if a chess clock is used rapid time-controls are common. The term refers only to the circumstances in which the game is played, not the relationship between the players or the intensity of the competition. Also called a casual game.

Gambit

A sacrifice (usually of a pawn) used to gain an early advantage of space and /or time in the opening.

GM

abbreviation for Grandmaster.

Good bishop

A bishop which has high mobility, typically because the player's pawns are on squares of color opposite to that of the bishop. (See .)

Grandmaster

The highest title a chess player can attain (besides World Champion). When used precisely, it is the title awarded by FIDE starting in 1950, but it can be used to describe someone of comparable ability. The term International Grandmaster or IGM would refer only to the FIDE title.

Grandmaster draw

A game in which the players quickly agree to a draw after making little or no effort to win. This may be a very boring game, e.g. 1.d4 d5 2.c4 c6 3.cxd5 cxd5 4.Nc3 Nf6 5.Nf3 Nc6 6.Bf4 Bf5 7.e3 e6 Draw Agreed, or a superficially exciting game played with a variation the players know leads to a draw, e.g. 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6 dxc6 5.0-0 Bg4 6.h3 h5 7.c3 Qd3 8.hxg4 hxg4 9.Nxe5 Bd6 (a pseudo-sacrifice of Black's queen) 10.Nxd3 Bh2+ 11.Kh1 Bd6+ and Black draws by perpetual check. Although originally used to refer to such games between grandmasters, the term is now used colloquially to refer to any such game.

Greek gift sacrifice

Also known as the classical bishop sacrifice, it is a typical sacrifice of a bishop by White playing Bxh7+ or Black playing Bxh2+ against a castled king in order to initiate a mating attack.

Half-open file

A file on which only one player has no pawns.

Handicap

See Odds.

Hanging

Unprotected and exposed to capture. Slang for en prise. To "hang a piece" is to lose it by failing to move or protect it.

Hanging pawns

Two friendly pawns abreast without friendly pawns on adjacent files. Hanging pawns can be either a strength (usually because they can advance) or a weakness (because they cannot be defended by pawns) depending on circumstances.

Heavy piece

A queen or rook, also known as a major piece.

Hole

A square that a player does not, and cannot in future, control with a friendly pawn. The definition is somewhat subjective: the square must have some positional significance for the opponent to be considered a hole - squares on the first and second ranks are not holes. On the other hand a square is a hole even if it can be controlled in the future with a pawn that has made a capture. An example of the hole is the square e4 in the Stonewall Attack.

Hypermodern

An opening system geared towards controlling the center with distant pieces as opposed to occupying it with pawns. See also Classical.

ICCA

See ICCF.

ICCF

The international Correspondence Chess Federation, founded in 1951 to replace the International Correspondence Chess Association (ICCA).

ICU

Irish Chess Union http://www.icu.ie/index.php publishes ICJ Irish Chess Journal

IGM

An abbreviation for the older term International Grandmaster. The modern usage is Grandmaster (GM).

IM

Abbreviation for the International Master title.

Inactive

See passive.

Initiative

The advantage that a player who is making threats has over the player who must respond to them. The attacking player is said to "have the initiative". s/he can often turn the play as s/he wills. The initiative often results from an advantage in time and/or space. The notion of the initiative was introduced by Capablanca.

Indian bishop

A fianchettoed bishop, characteristic of the Indian defences, the King's Indian and the Queen's Indian.

Indian defence

A chess opening that begins 1.d4 Nf6. Originally used to describe queen's pawn defences involving the fianchetto of one or both Black bishops, it is now used to describe all Black defences after 1.d4 Nf6 that do not transpose into the Queen's Gambit.

Insufficient material

An endgame scenario in which all pawns have been captured, and one side has only its king remaining while the other is down to just a king or a king plus one knight or one bishop. A king and bishop versus a king and bishop with the bishops on the same color is also a draw. The position is a draw because it is impossible for the dominant side to deliver checkmate regardless of play. Situations where checkmate is possible only if the inferior side blunders are covered by the fifty move rule. (See Draw (chess).)

Interference

This happens when the line between an attacked piece and its defender is interrupted by sacrificially interposing a piece.

Intermediate move

See zwischenzug.

International Arbiter

A tournament official who arbitrates disputes and performs other duties such as keeping the score when players are under time pressure.

International Grandmaster (IGM)

The original name of the FIDE title now simply called Grandmaster (GM).

International Master (IM)

A chess title that ranks below Grandmaster but above FIDE Master.

Internet chess server

This is an external server that provides the facility to play, discuss, and view chess over the internet, also abbreviated ICS.

Interpose

To move a piece between an attacking piece and its target, blocking the line of attack. Interposing a piece is one of the three possible responses to a check, the others being to move the king or capture the attacking piece.

Interzonal Tournament

A tournament organised by the FIDE, the second qualifying cycle of the World Chess Championship. The participants are selected from the top players of the zonal tournaments. The top ranking players qualify for the candidates tournament.

IQP

An abbreviation for Isolated Queen Pawn. See also isolani.

Irregular opening

Irregular openings are chess openings with an unusual first move from White. These openings are all categorized under the ECO code A00.

Isolani

refers to a d-Pawn with no Pawns of the same color on the adjacent c- and e-files, and is a synonym for 'Isolated Queen's Pawn'. The term was coined by Nimzovitch, who considered the isolani as a weapon of attack in the middle game but an endgame weakness; he considered the problem of hanging pawns to be related.

Isolated pawn

A pawn with no pawn of the same color on an adjacent file.

Italian bishop

A White bishop developed to the c4 square or a Black bishop developed to c5. This development is characteristic of the Italian Game, 1.e4 e5 2.Nf3 Nc6 3.Bc4, particularly the Giuoco Piano, 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5, where both players have Italian bishops. Likewise, "Italian" may be used as an adjective denoting an opening where one or both players has an Italian bishop, such as after 1.e4 e5 2.Nf3 Nc6 3.Nc3 Nf6 4.Bc4, the Italian Four Knights Game.

J'adoube

(from French) "I adjust". A player says "J'adoube" as the international signal that he intends to adjust the position of a piece on the board without being subject to the touched piece rule.

Symbol used for the king when recording chess moves in English.

Key square

1. An important square.

1. (Pawn endings) A square whose occupation by one side's king guarantees the achievement of a certain goal, such as the win of a pawn, see King and pawn versus king endgame.

KGA

The King's Gambit Accepted chess opening.

KGD

The King's Gambit Declined chess opening.

KIA

the King's Indian Attack chess opening.

Kibitz

As a spectator, making comments on a chess game that can be heard by the players. Kibitzing on a serious game while it is in progress (rather than during a post-mortem) is a breach of etiquette.

Kick

Attacking a piece, typically by a pawn, so that it will move.

KID

The King's Indian Defence chess opening.

King

see king

King Bishop

The bishop that was on the king-side at the start of the game. The terms King Knight and King Rook are also used. Sometimes abbreviated KB, KN, and KR respectively.

King hunt

A sustained attack on the enemy king that results in the king being driven a far distance from its initial position, typically resulting in its checkmate. Some of the most famous games featuring king hunts are Edward Lasker-Thomas, Polugaevsky-Nezhmetdinov, and Kasparov-Topalov.

King pawn

A pawn on the king's file, i.e. the e-file. Sometimes abbreviated KP. Also King Bishop Pawn (KBP), King Knight Pawn (KNP), and King Rook Pawn (KRP) for a pawn on the f, g, or h-file respectively.

Kingside

The side of the board where the kings are at the start of the game (the e through h files), as opposed to the queenside.

Knight

see knight

Knight pawn

A pawn on the knight's file, i.e. the b-file or g-file.

Knockout tournament

A tournament conducted as a series of matches in which the winner of each match advances to the next round and the loser is eliminated. Well known chess tournaments held in the knockout format include London 1851 and the 2007 Chess World Cup. Cf. and Swiss tournament.

Kotov syndrome

This phenomenon, first described by Alexander Kotov, can occur when a player does not find a good plan after thinking long and hard on a position. The player, under time pressure, then suddenly decides to make a move, often a terrible one which was not analysed properly.

Kt

The symbol sometimes used for the knight when recording chess moves in descriptive notation, mainly in older literature. A N is used instead in algebraic notation and in later descriptive notation to avoid confusion with K, the symbol for the king.

Laws of Chess

The rules of chess.

Lightning chess

A form of chess with an extremely short time limit, usually 1 or 2 minutes per player for the entire game.

Light squares

the 32 light-coloured squares on the chessboard, such as h1 and a8.

Light-square bishop

One of the two bishops moving on the light squares, situated on f1 or c8 in the initial position.

Line

• A sequence of moves, usually in the opening or in analyzing a position.

• An open path for a piece (Queen, Rook, or Bishop) to move or control squares.

Liquidation

See simplification.

Long diagonal

One of the two diagonals with eight squares (a1-h8 or h1-a8).

Loss

A loss for one of the two players, which may occur due to that player being checkmated by the other player, resigning, exceeding the time control, or being forfeited by the tournament director. Chess being a zero-sum game, this results in a win for the other player, except in the very rare circumstance where the tournament director forfeits both players, for example for cheating or both players exceeding the time control (the latter does not normally result in a double forfeit today).

Lucena position

A well-known rook and pawn versus rook endgame position in which the player with the extra pawn can force a win.

Luft

(from the German for air) Space made for a castled king to give it a flight square to prevent a back rank mate. Usually luft is made by moving a pawn on the second rank in front of the king.

Main line

The principal, most important, or most often played variation of an opening or piece of analysis. For example, 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.Nf3 0-0 6.Be2 e5 7.0-0 Nc6 8.d5 Ne7 is often referred to as the main line of the King's Indian Defence.

Major piece

A queen or rook, also known as a heavy piece.

Majority

A larger numbers of pawns on one flank opposed by a smaller number of the opponent's; often a player with a majority on one flank has a minority on the other.

Maróczy Bind

A bind on the light squares in the center, particularly d5, obtained by White by placing pawns on c4 and e4. Named for Géza Maróczy, it originally referred to formations arising in some variations of the Sicilian Defence, but the name is now also applied to similar setups in the English Opening and the Queen's Indian Defence. It was once greatly feared by Black but means of countering it have been developed since the 1980s and earlier.

Match

A competition between two individuals or two teams. A match may be the entire competition, or it may be a round in a knockout tournament or team tournament. Unlike in some sports where the word match is sometimes used to describe a single game, a chess match always consists of at least two games (and often many more).

Mate

Short for checkmate.

Material

All of a player's pieces and pawns on the board. The player with pieces and pawns of greater value is said to have a "material advantage". When a player gains a material advantage they are also said to be "making material". (See Chess piece point value.)

Mating attack

An attack aimed at checkmating the enemy king.

MCO

Modern Chess Openings, a popular chess opening reference. Often the edition is also given, as in MCO-14, the 14th edition. Cf. ECO.

Middlegame

The part of a chess game that follows the opening and comes before the endgame, beginning after the pieces are developed in the opening. This is usually roughly moves 20 through 40.

Miniature

A short game (usually no more than 20 to 25 moves). However, a significant minority of authors include games up to 30 moves. John Nunn, 101 Brilliant Chess Miniatures, Gambit Publications, 1999, p. 6. ISBN 1-901983-16-1. Usually only decisive games (not draws) are considered miniatures, and a miniature should not be spoiled by an obvious blunder by the losing side. A miniature may also qualify as a brilliancy. The Opera game is a famous example. Sometimes called a brevity (chiefly British).

Minor exchange

The exchange of a bishop for a knight.

Minor piece

A bishop or knight.

Minority attack

An advance of pawns on the side of the board where one has fewer pawns than the opponent, usually carried out to provoke a weakness.

Mobility

The ability of a piece, or of a player's pieces collectively, to move around the board. (In computer chess this is often measured by the number of legal moves available.)

Mobile pawn center

Pawns on central squares able to advance without becoming weak.

Move

A turn by each player, but also used to refer to a ply.

Move order

The sequence of moves one chooses to play an opening or execute a plan. Different move orders often have different advantages and disadvantages. For example, 1.d4 Nf6 2.Nf3 avoids the Budapest Gambit (2.c4 e5!?), but makes it impossible for White to play the Sämisch Variation (2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.f3) or Four Pawns Attack (5.f4) against the King's Indian Defence, and to transpose to certain lines of the Nimzo-Indian Defence and Queen's Gambit Declined, Exchange variation where the knight goes to e2 instead of f3. (See transposition.)

Mysterious rook move

A horizontal rook move to a closed file. An example of prophylaxis, it is intended to discourage the opposing player from opening the file.

Symbol used for the knight when recording chess moves in English.

NCO

Abbreviation sometimes used for the chess opening reference Nunn's Chess Openings. Cf. ECO and MCO.

NN or N.N.

Used in a game score in place of a player whose name is not known. The origin of this usage is uncertain. It may be an abbreviation of the Latin nomina (names), or it may be short for the Latin phrase nomen nescio (names unknown). See also Amateur.

Norm

A performance at a chess tournament that indicates a player is ready to receive a title, or the level of performance needed. In addition to other requirements, a certain number of norms is generally required to earn a title. See Grandmaster and International Master.

Novelty

A new move in the opening. Sometimes called a "theoretical novelty" or "TN."

Odds

This refers to the stronger player giving the weaker player some sort of advantage, such as in material, extra moves, time on the clock, or some combination thereof. One relatively small form of odds is "draw odds", where a drawn game is deemed the same as a win for the weaker player. In "pawn odds" the stronger player starts without one of his pawns and plays as White (in a match at odds, the players may alternate colors). At pawn and move odds the stronger player has the black pieces and begins the game without one of her pawns, traditionally the f-pawn. If the gap in skill is greater the stronger player might give "pawn and two moves", where she starts without one of her pawns, plays as Black and lets the opponent begin the game by playing two moves in succession. If the difference in skill is even greater, the stronger player may give odds of one or more of the queen-side pieces, e.g. odds of (queen) knight, (queen) bishop, (queen) rook, queen, or both the queen rook and queen knight (removing the relevant piece before the game starts).

Since the advent of the chess clock, time odds have become more common than material odds. The stronger player will begin the game with only one or two minutes on the clock, while the weaker player is given five or more minutes on the clock. A very unusual and difficult form of odds game is the "ringed piece", where a ring is put around one of the stronger player's pieces (for example the queen knight) and the stronger player must checkmate with that piece; any other result is deemed a win for the weaker player.

Offhand game

See skittles.

Olympiad

An international team chess tournament organized biennially by FIDE. Each team represents a FIDE member country.

Open file

A file on which there are no pawns. A file on which only one player has no pawns is said to be half-open.

Open game

• A game in which exchanges have opened files and diagonals, as opposed to a