Glossary of chess

This glossary of chess explains commonly used terms in chess, in alphabetical order. Some of these terms 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 Glossary of chess problems; for a list of named opening lines, see List of chess openings; for a list of chess-related games, see List of chess variants; for a list of terms general to board games, see Glossary of board games.

A

absolute pin: A pin against the king is called absolute since the pinned piece cannot legally move out of the line of attack (as moving it would expose the king to check).^[1] Cf. relative pin.
active: Describes a piece that threatens a number of squares, or that has a number of squares available for its next move. It may also describe an aggressive style of play.^[2] Antonym: passive.
adjournment: Suspension of a chess game with the intention to finish it later. It was once very common in high-level competition, often occurring soon after the first time control, but has been mostly abandoned due to the advent of computer analysis.^[3] See also sealed move.
adjudication: A way to decide the result of an unfinished game. A tournament director, or an impartial and strong player, will evaluate the final position and assign a win, draw, or loss assuming best play by both players.^[4]
adjust: See touch-move rule. To adjust the position of a piece on its square without being required to move it. A player may do this only on their turn, and must first say "I adjust", or the French equivalent "J'adoube".^[5]
advanced pawn: A pawn that is on the opponent's half of the board (the fifth rank or higher for White; the fourth rank or lower for Black). 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 mobility. An advanced passed pawn that threatens to promote can be especially strong.^[6]
advantage: A better position with the chance of winning the game. Evaluation factors can include space, time, material, and threats.^[2]
Alekhine's gun: A special form of battery in which a queen backs up two rooks on the same file.^[7]
algebraic notation: The standard way to record the moves of a chess game, using alphanumeric coordinates for the squares.^[8] Also called standard notation.^[9] Abbr. AN.
amateur: Any player whose main occupation is not chess.^[10] 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.^[10]^[11] 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.^[11] See also NN.
analysis: The study of a game or a position, in order to evaluate the quality of the moves and various other aspects of the game or position. At the end of a game, the players will often do an analysis of the game. See also post-mortem.^[2]
annotation: Written commentary on a game or a position using words, chess symbols, and/or notation.^[2]
announced mate: A practice, common in the 19th century, whereby a player would announce a sequence of moves, believed by them to constitute best play by both sides, that led to a forced checkmate for the announcing player in a specified number of moves (for example, "mate in five").^[12]
antipositional: A move or a plan that is not in accordance with the principles of positional play.^[13] 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, their advance can create irreparable weaknesses.^[14]
Anti-Sicilian: An opening variation 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).^[15]
Arabian mate: A checkmate that occurs when the knight and rook trap the opposing king in a corner.^[16]
arbiter: An official responsible for overseeing chess tournaments and ensuring that the rules of chess are obeyed.
arena: A type of tournament without a fixed amount of rounds.^[17]
Armageddon game: A game that is guaranteed to produce a decisive result, because if there is a draw it is ruled a victory for Black. In compensation for this White is given more time on the clock. Often White is given five minutes, and Black four. This format is typically used in playoff tiebreakers when shorter blitz games have not resolved the tie.^[18]
artificial castling: Refers to a maneuver of several separate moves by the king and by a rook where they end up as if they had castled. Also known as castling by hand.^[19]
attack: An aggressive action on a part of the chessboard, or to threaten the capture of a piece or pawn.^[20] See also counterattack, discovered attack, double attack, mating attack, and minority attack. Antonym: defense.
attraction: A type of decoy involving a sacrifice of a minor or major piece on a square next to the enemy king, forcing the king to abandon the defense of another square. For example (see diagram), the black queen has interposed to block a check from the white queen, and White can check the king from the opposite direction to win the queen.^[21]
automaton: An automaton is a self-operating machine. In chess, it refers to chess-playing machines that were in fact hoaxes and under the control of hidden human players. Automatons stirred up great interest in the 18th and 19th centuries and inspired early thoughts of the possibility of artificial intelligence. By far, the most famous chess-playing "automaton" was The Turk, whose secret of human control was kept for a very long time. The first true automaton El Ajedrecista was created by Leonardo Torres y Quevedo.

B

B: Symbol used for the bishop when recording chess moves in English.^[22]
back rank: A player's first rank (the rank on which the pieces stand in the starting position). White's back rank is Black's eighth rank; Black's back rank is White's eighth rank.^[23] Also called home rank and first rank.
back-rank mate: A checkmate delivered by a rook or queen along a back rank from which the mated king is unable to move because it is blocked by friendly pieces (usually pawns) or squares under attack on the player's second rank.^[23] Also called back-row mate.
back-rank weakness: A situation in which a player is under threat of a back-rank mate and, having no time/option to create an escape for the king, must constantly watch and defend against that threat, for example by keeping a rook on the back rank.^[23]
backward pawn: A pawn that is behind a pawn of the same color on an adjacent file and that cannot be advanced with the support of another pawn.^[24]
bad bishop: A bishop that is hemmed in by the player's own pawns.^[25] Cf. good bishop.
bare king: A position in which a king is the only man of its color on the board.^[26]
Basque chess: Or Basque system. A chess competition in which the players simultaneously play each other two games on two boards, each playing White on one and Black on the other. There is a clock at both boards. It removes the bonus in mini-matches of playing White first. Basque chess was first played in the 2012 Donostia Chess Festival in the Basque Country, Spain.^[27]
battery: Gathering pieces along a line of action in somewhat varying setups. In games, it usually means to line up rooks and/or the queen on a file, or to place a bishop and a queen on a diagonal.^[20] In chess problems, battery refers to 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 (or a threat other than a check) will be delivered.^[28] See also Alekhine's gun.
BCF: British Chess Federation, the former name of the English Chess Federation.^[29] See also ECF.
BCM: An abbreviation for the British Chess Magazine.^[30]
BCO: An abbreviation for the 1982 openings reference book Batsford Chess Openings, by Raymond Keene and Garry Kasparov. The second edition (1989) is often called BCO-2.^[31] Cf. ECO and MCO.
best play: The theoretical absolute and ideal best moves from any given position.^[32]
big pawn: A bad bishop stuck behind its own pawns and defending them—effectively doing the work of a pawn.^[33]
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.^[34] See also squeeze.
bishop: A piece that may move along diagonals without jumping.
bishop pair: The player with two bishops is said to have the bishop pair. Two bishops are able to control the diagonals of both colors. In open positions, two bishops are considered to have an advantage over two knights, or a knight and a bishop.^[20] Also called the two bishops.
bishop pawn: Or bishop's pawn. A pawn on the bishop's file, i.e. the c-file or f-file. Sometimes abbreviated "BP".^[35]
bishops on opposite colors: Or bishops of opposite colors. A situation in which one player has only a light-square bishop remaining while the other has only a dark-square bishop remaining. In endgames, this often results in a draw if there are no other pieces than pawns, even if one side has a material advantage of one, two or even three pawns, 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.^[36]
black: The dark-colored squares on the chessboard are often referred to as "the black squares" even though they are often some other dark color. Similarly, "the black pieces" are sometimes actually some other (usually dark) color.^[37] See also white.
Black: The designation for the player who moves second, even though the pieces ("the black pieces") are sometimes actually some other (usually dark) color.^[38] See also White and first-move advantage.
blind chess: See Kriegspiel.
blindfold chess: A form of chess in which one or both players are not allowed to see the board.^[39]
blind pigs: A pair of rooks on the opponent's second rank are referred to as "pigs" as they tend to devour pawns and pieces, and "blind pigs" if they cannot find the mate.^[40]
blitz chess: [from German: Blitz, "lightning"] A fast form of chess with a very short time limit, usually three or five minutes per player for the entire game. With the advent of electronic chess clocks, the time remaining is often incremented by one or two seconds per move.^[41]
blitzkrieg: A blitzkrieg is sometimes used to describe a quick attack on the f7- or f2-square early in the game.^[42]^[43]
blockade: The placement of a piece directly in front of an enemy pawn, where it obstructs the pawn's advance, and hinders the movements of the other enemy pieces. The enemy pawn provides some shelter to the piece that is blocking it, thereby protecting it from attacks by enemy pieces. A blockade is most effective against passed or isolated pawns. The ideal piece to use as a blockader is the knight. This strategy was famously formulated by Aron Nimzowitsch in 1924.^[44]^[45]
blocked position: A position where both sides are constrained from making progress, typically by interlocking pawn chain(s) dividing the available space into two camps.^[46] See also closed game.
blunder: A very bad move, an oversight (indicated by "??" in chess annotation).^[20]
board: 1. See chessboard.; 2. An assignment in team chess, e.g. first board, second board, etc.
board one: See first board.
Boden's Mate: Boden's Mate, named for Samuel Boden, is a checkmate pattern in which the king, usually having castled queenside, is checkmated by two crisscrossing bishops. Immediately prior to delivering the mate, the winning side typically plays a queen sacrifice on c3 or c6 to set up the mating position.^[47]
book draw: An endgame position known to be a draw with perfect play. Historically this was established by reference to chess endgame literature, but in simplified positions computer analysis in an endgame tablebase can be used.^[48] Also called theoretical draw.
book move: An opening move found in 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).^[49]
book win: An endgame position known to be a win with perfect play. Historically this was established by reference to chess endgame literature, but in simplified positions (currently seven pieces or fewer) computer analysis in an endgame tablebase can be used.^[50]
break: A move that gains space and therefore freedom of movement, or the opening of a blocked position by the advance or capture of a pawn.^[51] See also pawn break.
breakthrough: Penetration of the opponent's position, or destruction of the defense, often by means of a sacrifice.^[20]
brevity: [chiefly British] See miniature.
brilliancy: A game that contains a spectacular, deep and beautiful strategic idea, combination, or original plan.^[51]
brilliancy prize: A prize awarded at some tournaments for the best brilliancy played in the tournament.^[52]
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.^[53]
bughouse chess: A popular chess variant played with teams of two or more.^[54]
building a bridge: Making a path for a king in the endgame by providing protective cover against checks from line pieces. A well-known example is the Lucena position.^[55]
bullet chess: Each side has one minute to make all their moves.^[56]
bust: [colloq.] A refutation of an opening, an opening line, a tactic, or a previously published analysis.^[57]^[58]
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 (½ point).^[58]

C

Caïssa: Known as the goddess or muse of chess, whose name is taken from a nymph in a 1763 poem, Caïssa or The Game at Chess, by Sir William Jones.^[59]
calculate: To plan mentally a series of moves and consider possible responses, without actually moving the pieces.^[20]
Candidate Master: A chess title ranking below FIDE Master.^[60] Abbr. CM.
candidate move: A move that seems good upon initial observation of the position, and that warrants further analysis.^[61]
Candidates Match: A knockout match in the Candidates Tournament.^[62]
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.^[63]
can opener: [colloq.] The plan of attacking a kingside position (sometimes a fianchettoed one) by advancing the h-pawn with the intention of opening a file near the defender's king.^[64]^{[verification needed]}
capped piece: A particular piece with which one player attempts to deliver checkmate. The requirement to checkmate with the capped piece constitutes a handicap. When the capped piece is a pawn, it is called a pion coiffé [from French, "capped pawn"].^[65]
capture: A move by a pawn or piece that removes from the board the opponent's pawn or piece. The capturing piece then occupies the square of the captured piece, except in the case of a capture that is done en passant.^[66]
castling: A move in which the king and a rook are moved at the same time. It moves the king from the center to a flank where it usually is safer, and it develops the rook. It is the only time two pieces are moved in a turn. Castling can be done on either the kingside (notated 0-0) or the queenside (0-0-0). Castling cannot be done in reply to a check, nor if the king were to cross or land on a square which is under attack by the opponent, nor if either the king or the rook involved has already moved.^[67]^[68]
castling into it: A situation where one side castles and a result is that the king is in more danger at the destination than on the initial square, either immediately or because lines and diagonals can be more readily opened against it.^[69]
castling long: Castling queenside; in chess notation: 0-0-0.^[67] Also called long castling.^[70]
castling rights: The ability to castle under the laws of chess.
castling short: Castling kingside; in chess notation: 0-0.^[67] Also called short castling.^[70]
casual game: See friendly game.
category of a 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.^[71]
CC: An abbreviation sometimes used for correspondence chess or for chess club.
center: Or centre. The four squares in the middle of the board.^[72] See also expanded center. Sometimes short for pawn center. A king "in the center" can refer to an uncastled king on a center file.
center file: Or centre file. The king's file (e-file) or queen's file (d-file).
center pawn: Or centre pawn. A pawn on the king's file (e-file) or queen's file (d-file).^[73]
centipawn: A unit of evaluation used by chess engines, e.g. an evaluation of +1.32 is worth 20 centipawns more than an evaluation of +1.12. Historically a centipawn corresponded to a material value of 0.01 of a pawn; however, the strongest modern engines no longer rate pawns as worth 1.^[74]
central file: See center file.
centralization: Moving a piece or pieces toward the center of the board, where they will not only control the center, but also extend their influence to other areas. Pieces are best placed near the center of the board, because they increase their power and maneuverability. Knights in particular benefit from being centralized.^[75] Antonym: decentralization.^[76]
central pawn: See center pawn.
cheapo: Slang for a primitive trap, often set in the hope of swindling a win or a draw from a lost position.^[77] Also called cheap shot.
check: A direct attack on the king by an enemy man. The attacked king is said to be in check. There are only three possible immediate responses to a check: capturing the attacking piece, moving the king to an unattacked square, or interposing a piece between the attacker and the king. In casual games a player usually announces "check"; however, this is not a requirement in tournament games.^[78]
checkmate: Often shortened to mate. A position in which a player's king is in check and the player has no legal move (i.e. cannot move out of or escape the check). A player whose king is checkmated loses the game.^[79]
chess annotation: See annotation.
chess blindness: The failure of a player to see a good move or danger that should normally be considered obvious. The term was coined by Siegbert Tarrasch. Similar to Kotov syndrome.^[80]
chessboard: The chequered board used in chess, consisting of 64 squares (eight rows by eight columns) arranged in two alternating colors, light and dark.^[81]
chess clock: A device made up of two adjacent clocks and buttons, keeping track of the total time each player takes for their moves. Immediately after moving, the player hits their button, which simultaneously stops their clock and starts their opponent's. The picture shown displays an analogue clock where the term flag fall originates. Modern clocks are digital.^[82]
chess club: An in-person, local chess play organization.
chessmen: The movable figures placed on the board in a game of chess. Includes both pieces and pawns.^[83] Singular: chessman.
chess notation: See notation.
chess opening: See opening.
chess problem: Also called composition.
chess set: The thirty-two pieces required for a game, plus a chessboard.
chess variant: A chess-like game played using a board, pieces, or rules different from standard chess.^[84]
Chess960: A synonym for Fischerandom.
chop wood: Slang for capturing or exchanging pieces.^[85] See also wood.
classical: 1. An opening system geared towards forming a full pawn center. Classical ideas were challenged by hypermodern ideas.^[72]; 2. A game using a longer time control such as 40/2; the opposite of fast chess categories such as rapid, blitz or bullet.^[86]
classical bishop sacrifice: See Greek gift sacrifice.
clearance: Removal of piece from a square, rank, file or diagonal so that another piece may use it. It often involves sacrificing the piece that blocked the position.^[87] See Clearance sacrifice.
clock move: In a game played clock move, a move is considered completed only after the clock is pressed. For example, one could touch a piece, then move a different piece—as long as the player has not pressed their clock button. This way of playing is uncommon but can be seen in casual games or blitz games.^[88]
clock time: Time (consumed or remaining) on the chess clock, in a tournament game.^[89]
closed file: A file on which White and Black each have a pawn.^[90]
closed game: Or close game. A closed game has few open lines (files or diagonals). It is generally characterized by interlocking pawn chains, cramped positions with few opportunities to exchange, and extensive maneuvering behind lines. Such a game may evolve and later become an open game.^[91] Cf. open game. See also positional play.
Closed Game: A Closed Game is a particular opening that begins with the moves 1.d4 d5. It is also known as a Double Queen's Pawn Opening or Double Queen's Pawn Game.^[92] See also Open Game and Semi-Open Game.
closed tournament: A tournament in which only invited or qualifying players may participate. Also called invitational tournament. Cf. open tournament.
CM: An abbreviation for the Candidate Master title.
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 or blitz chess. The Blackburne Shilling Gambit is a typical example of coffeehouse play.^[93]
color: Or colour. The white or black pieces, and the white or black squares. The actual pieces and squares may be other colors, usually light and dark, but they are referred to as white and black.^[83] See White and Black in chess.
colorbound: Or colourbound. The property of a piece to access only squares of one color. In standard chess, each bishop is colorbound to either the white or black squares.
colors reversed: Or colours reversed. With colors reversed refers to opening moves by White normally played by Black, or vice versa. An example is the King's Indian Attack, where White's opening setup mirrors Black's setup in the King's Indian Defense. In such openings, White necessarily has an extra tempo compared to Black. Also called a reverse opening.^[94]
combination: A sequence of moves, including forced moves, and often involving a sacrifice, to gain an advantage.^[72]
compensation: That which is gained in return for a loss – often a positional improvement in return for loss of material. If material is sacrificed there may be a gain in development, or if a minor piece is exchanged for two or three pawns, the pawns would be the compensation.^[95]
computer move: A move that seems likely to have been played by a computer rather than a human, either because the move seems counterintuitive, or to not make immediate sense, or to eventually make sense but not until deep into the game. Computer moves seem to be what they are: moves based on millions of brute-force calculations, and not on intuition, aesthetics, or emotion. A computer move would overlook a dramatic capture that might cause an opponent to immediately resign, in favor of an obscure move that may turn out to be only slightly better. At one time the term was used disparagingly, but its meaning has evolved as computers have improved. It is occasionally used to suggest that a player has been assisted by computer.^[96]^[97]
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.^[72] See also connected pawns.
connected pawns: Refers to two or more pawns of the same color on adjacent files.^[75] Cf. isolated 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.^[98] See also doubled rooks.
consolidation: The improvement of a player's position by the reposition of one or more pieces to better square(s), typically after a player's attack or combination has left their pieces in poor positions or uncoordinated.^[99]
consultation game: A game in which two or more players consult with each other to jointly decide the moves for one side. Consultation games may also involve teams of two or more players playing on both sides.^[100]
continuation: See variation.
control: When a player's pawn, piece or pieces guard a square, or squares, or a file, or a rank in such a way that the territory can be advantageously used; and the opponent is prevented from using the territory.^[101] Also, the player that has the initiative has control.
control of the center: Having one or more pieces that attack any of the four center squares; an important strategy, and one of the main aims of openings.^[102]
cook: In chess problems, an unintended duplicate solution, or a refutation.^[103] See also Glossary of chess problems § cook.
coordination: The quality of multiple pieces working together, mutually supporting and complementing one another.^[104]
corr.: An abbreviation for correspondence game.
correspondence chess: Chess played at a long time control by long-distance correspondence. Traditionally correspondence chess was played though the post; today it is usually played over a correspondence chess server or by email. Typically, one move is transmitted in every correspondence.^[105]
corresponding squares: Corresponding squares are pairs of squares such that when a king moves to one square, it forces the opponent's king to occupy the other square in order to hold the position. Corresponding squares usually occur in pawn endgames. The theory of corresponding squares has developed to include complex calculations based on math-like formulas.^[106] Also called related squares. Cf. opposition.
counterattack: An attack that responds to an attack by the opponent.^[107]
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); the 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 Counterattack]; 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.^[108]
counterplay: The defending side's own aggressive action.^[109]
country move: A disparaging term for a move considered unsophisticated, especially an unnecessary single-step advance of the rook's pawn in the opening. The term was popular in London in the late 19th century.^[110]
cover: To protect a piece or control a square.
cramped: Having limited mobility in a position.^[111]
critical position: The moment in a game or opening when the evaluation shows that things are about to change, either towards an advantage for one player, or towards equality; a wrong move can be disastrous.^[109]
critical square: See key square.
cross-check: A cross-check is a check played in reply to a check, especially when the original check is blocked by a piece that itself either delivers check or reveals a discovered check from another piece.^[112]
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. There may be one column for each successive round, or, in a round-robin tournament, there may be one column for each player, with the players in the same order in the columns as in the rows. For each player, the table cells on the player's row record the results of the player's games, using 1 for a win, 0 for a loss, and ½ 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.)^[113] For examples see Hastings 1895 chess tournament, Nottingham 1936 chess tournament, and AVRO tournament.
crush: Slang for a quick win, especially an overwhelming attack versus poor defensive play. A crushing move is a decisive one.

D

dark-square bishop: One of the two bishops that moves only on the dark squares. In the starting position, White's dark-square bishop is on c1; Black's is on f8.^[38] Often shortened to dark bishop^[76] or DSB. Cf. light-square bishop.
dark squares: The 32 dark-colored squares on the chessboard, such as a1 and h8. A dark square is always located at a player's left-hand corner.^[38] Cf. light squares.
dead draw: A drawn position in which neither player has any realistic chance to win. In the strict sense, dead draw may refer to a position in which it is impossible for either player to win (such as insufficient material). In a broader sense, it may refer to a simple, lifeless position that would require a major blunder before either side would have a chance to win.^[114]
dead position: A position where neither player can mate the opponent's king with any series of legal moves (e.g. knight and king against a bare king). This position is drawn.^[116]
decoy: This is a tactic used to lure an enemy man away from its defensive position.^[117]^[118] See also deflection and attraction.
defense: 1. A move or plan to meet the opponent's attack.^[109]; 2. Part of the name of openings played by Black; e.g. the Scandinavian Defense, King's Indian Defense, English Defense, etc.^[109]
deflection: A decoy tactic that involves luring an enemy piece away from a good square; typically, away from a square on which it defends another piece or threat. Deflection is thus closely related to overloading.^[119] See also attraction.
demonstration board: A large standing chess board used to analyze a game or show a game in progress. Johann Löwenthal invented the demonstration board in 1857.^[120]
descriptive notation: A system of recording chess moves, used primarily in the English and Spanish speaking countries until the 1980s. Descriptive notation is based on natural language descriptions of chess moves rendered in abbreviated form, for example "pawn to queen's bishop's fourth" is rendered as "P-QB4". Now replaced by the standard algebraic notation.^[121]
desperado: A piece that seems determined to give itself up, typically to bring about stalemate or perpetual check. Also an en prise or trapped piece that sacrifices itself for the maximum compensation possible.^[122]
development: The movement of non-pawn pieces in the opening from their original squares to squares where they can be more active. Development of one's pieces is one of the objectives of the opening phase of the game.^[117]
diagonal: A line of squares of the same color touching corner to corner, along which a queen or bishop can move.^[123]
discovered attack: An attack made by a queen, rook or bishop when another piece or pawn moves out of its way.^[117]
discovered check: A discovered attack to the king. This occurs when a player moves a piece, resulting in another piece putting their opponent's king in check.^[124]^[125]^[126]
diversionary sacrifice: Especially in the middlegame, the sacrifice of a decoy piece.^[127]
domination: From endgame studies, control of all movement squares of an enemy piece.^[128]
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, for example in a discovered attack when the moved piece also makes a threat.^[117]
double check: A check delivered by two pieces at the same time. A double check necessarily involves a discovered check. By its nature a double check cannot be met by interposing a defending piece in the line of attack, or by capturing an attacker; when subjected to a double check, the attacked king must move, which makes the double check especially powerful as an attacking tactic.^[129]
doubled pawns: Two pawns of the same color on the same file; generally considered a weakness due to their inability to defend each other.^[123]
doubled rooks: A powerful configuration in which a player's two rooks are placed on the same file or rank with no other men between them. They defend each other and attack along the shared file or rank, as well as two additional ranks or files. The configuration can be especially decisive in the endgame.^[130]
double fianchetto: A player's king bishop and queen bishop have both been fianchettoed.^[131]
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 by stalemate, by a dead position, by the threefold repetition rule, by the fifty-move rule, by the fivefold repetition rule and by the seventy-five-move rule. A position is said to be a draw (or a "drawn position" or "theoretical draw") 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 ½ point, although in some matches only wins are counted and draws are ignored.^[117]
draw by agreement: A game that is ended by both players' accepting a draw.^[132] See also resign.
draw death: Hypothetical scenario whereby elite-level chess players, aided by modern computer analysis, become so good that they never make mistakes, leading to endless drawn games (since chess is widely believed to be drawn with best play from both sides).^[133]
drawing line: An opening variation that commonly ends in a draw.^[134]
drawing weapon: An opening line played with the intent of drawing the game.^[135]
drawish: An adjective describing a position or game that is likely to end in a draw.^[136]
draw odds: A type of chess handicap where one player (Black in an Armageddon game) has only to draw in order to win the match.^[137]
draw offer: A proposal by a player to the opponent that the game be drawn by agreement.^[138]
dynamism: A style of play in which the activity of the pieces is favored over more positional considerations, even to the point of accepting permanent structural or spatial weaknesses. Dynamism stemmed from the teachings of the Hypermodern school and challenged the dogma found in more classical teachings, such as those put forward by Wilhelm Steinitz and Siegbert Tarrasch.^[139]

E

eat: [colloq.] To remove the opponent's piece or pawn from the board by taking it with one's own piece or pawn.^[140]^[141] See also capture.
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 the British Chess Federation (BCF) until 2005 when it was renamed.
ECU: The European Chess Union (ECU) is the continental association for chess in Europe.
ECO: The Encyclopaedia of Chess Openings (ECO), a standard and comprehensive chess opening reference. Also a classification system (ECO code) for openings that assigns an alphanumeric code from A00 to E99 to each opening.
edge: A small but meaningful advantage in the position against one's opponent. It is often said White has an edge in the starting position, since White moves first (see First-move advantage in chess).^[142]
eighth rank: The rank on which pawns promote (rank eight for White; rank one for Black). Also called last rank.
Elo rating system: The Elo rating system is a method for calculating the relative skill levels of chess players, named after Arpad Elo. Since 2012, FIDE publishes a monthly international chess rating list using the Elo system.^[143]
endgame: The third and last phase of the game, when there are few pieces left on the board. The endgame follows the middlegame.^[143]
endgame tablebase: A computerized database of endgames with a small number of pieces, providing perfect play for both players, and thus completely solving those endgames. As of 2012, tablebases have been calculated for all positions with up to seven pieces.^[144]
en passant: [from French, "in the act of passing"] The rule that allows a pawn that has just advanced two squares to be captured by an enemy pawn that is on the same rank and adjacent file. The pawn can be taken as if it had advanced only one square. Capturing en passant is possible only on the next move.^[145] Abbr. e.p.
en prise: [from French, "in a position to be taken",^[146]^[147] often italicized] En prise describes a piece or pawn exposed to a material-winning capture by the opponent. This is either a hanging piece, an undefended pawn, a piece attacked by a less valuable attacker, or a piece or pawn defended insufficiently. For instance, 1.e4 Nf6 2.Nf3? leaves White's e-pawn en prise.^[148]^[149]
e.p.: An abbreviation for en passant.
epaulette mate: A checkmate position where the king is blocked on both sides by its own rooks.^[150]
EPD: An abbreviation for Extended Position Description.
equalize: Or equalise. To reach a position where the players have equal chances of winning, referred to as equality, or a position that is equal. In the opening, because White has the advantage of the first move, the immediate goal for Black is to achieve equality.^[151]
escape square: See flight square.
evaluation: Or simply eval. The analysis of a position. A computer or engine evaluation is a means of assigning a number value to a position, based not on intelligence, but on algorithms, which vary from engine to engine and depend on engine strength. Engine evaluations have foibles and imperfections even when functioning as designed. If an engine describes a position as +2.50, the plus sign ("+") indicates the position is favorable to White; a minus sign ("−") indicates the position is favorable to Black. The number can correspond to the approximate value of pieces, although engines use other factors besides material. The notation +2.50 indicates that White is ahead by two and one-half pawns. The notation +M4 (or sometimes #4) indicates that White can force checkmate in four moves.^[152]^[153]^[154] Cf. analysis.
exchange: To swap or trade pieces by capture. Usually the pieces are of equal value (i.e., rook for rook, knight for knight, etc.), or of bishop for knight (two pieces that are considered approximately equal in value).^[155] Also called even exchange.
exchange, the: The advantage of a rook over a minor piece (knight or bishop). The player who captures a rook for a minor piece is said to have "won the exchange", the player who has lost the rook has "lost the exchange". An exchange sacrifice is giving up a rook for a minor piece.^[148]
exchange variation: This is a type of opening in which there is an early, voluntary exchange of pawns or pieces.^[156]
exhibition: Chess games played for the public in various formats and for various purposes, often to promote the game, or a particular match or player, or as a fundraiser. An exhibition may pit two masters against each other, and normally use chess clocks. In a simultaneous exhibition, one player takes on a number of opponents at once, and it is often not timed. A blindfold exhibition is the same but more challenging, since the exhibitor plays without seeing the boards.^[157]
expanded center: The central sixteen squares of the chessboard.^[158]
exposed king: A king lacking pawns to shield it from enemy attack.^[159]
extended fianchetto: See fianchetto.
Extended Position Description: 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.^[160] Abbr. EPD.

F

family fork: A knight fork that simultaneously attacks the enemy king (giving check), queen, and possibly other pieces. Also known as a family check.^[161]
FAN: An abbreviation for figurine algebraic notation, which substitutes symbols for letters to represent piece names (e.g. ♘f3 instead of Nf3).^[162]
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 rapid chess, blitz chess, and bullet chess.
FEN: An abbreviation for Forsyth–Edwards Notation.
FGM: An abbreviation for the FICGS Grandmaster title.
fianchetto: To develop a bishop to the board's longest diagonal on the file of the adjacent knight (b2 or g2 for White; b7 or g7 for Black). The fianchetto of both bishops by a player is called a double fianchetto. Less common is to develop a bishop to the rook's file (a3 or h3 for White; a6 or h6 for Black), called extended fianchetto.^[131] The Italian word ("little flank") is pronounced /ˌfiənˈkɛtoʊ/ or /ˌfiənˈtʃɛtoʊ/ in English, while its name sounds like [fjaŋˈketto] in Italian.^[163]^[164]
FICGS Grandmaster: A correspondence chess title calculated by the FICGS (Free Internet Correspondence Games Server) organization.^[165]
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.^[166]
FIDE Master: A chess title ranking below International Master.^[167] Abbr. FM.
FIDE rating: See Elo rating system.
fifty-move rule: A draw may be claimed if no capture or pawn move has occurred in the last fifty moves by either side.^[168] For the occurrence of seventy-five such moves, see seventy-five-move rule.
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, "f-file" and "king bishop file" both denote the squares f1–f8 (or KB1–KB8 in descriptive notation).^[166]
fingerfehler: [from German, "finger mistake"] An error caused by unthinkingly touching the wrong piece or releasing a piece on the wrong square, forcing the player to move that piece in accordance with the touch-move rule.^[169]
first board: In team chess, the player who is assigned to face the strongest opponents. Also called top board and board one. Second board faces the next strongest players, followed by third board, and so on. Generally board assignments must be made before the competition begins and players may not switch boards, although reserve players are often allowed as substitutes.
first-move advantage: The slight (by most accounts) advantage that White has by virtue of moving first.^[166]
first player: The expression "the first player" is sometimes used to refer to White.
first rank: See home rank.
Fischerandom: Also known as Chess960. A variation of chess invented and advocated by Bobby Fischer. The pieces and pawns have their normal moves, but the setup of pieces on the first rank is random, except that two rules must be followed: the king must be placed on a square between the rooks, and the bishops are placed on squares of opposite color. Black's pieces are placed opposite White's. Castling may be done; the special castling rules incorporate the normal castling in classic chess.^[170]^[171]
Fischer delay: A time control method with time delay, invented by Bobby Fischer. When it becomes a player's turn to move, the delay is added to the player's remaining time.^[172]
fish: [derogatory slang] A weak or easily defeated player or players. See also woodpusher.
fivefold repetition: A game is drawn if the same position occurs five times, with specific meaning of occurrence as under threefold repetition.^[173]
five-minute chess: See blitz chess.
flag: Part of an analogue chess clock, usually red, that 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.^[166]
flag-fall: The event when the allotted time of a player has just expired; the player has run out of time.^[115]
flank: The queenside a-, b-, and c-files; or the kingside f-, g-, and h-files. Distinguished from the center d-file and e-file.^[174] Also called wing.
flank opening: An opening played by White and typified by play on one or both flanks.^[175]
flight square: A square to which a piece can move, that allows it to escape attack.^[161] Also called escape square. See also luft.
FM: An abbreviation for the FIDE Master title.
FOA: An abbreviation for the FIDE Online Arena.
Fool's mate: The shortest possible chess game ending in mate: 1.f3 e5 2.g4 Qh4# (or minor variations on this).^[176]
forced mate: A sequence of two or more moves culminating in checkmate that the opponent cannot prevent.^[177]
forced move: A move that is the only one to not result in a serious disadvantage for the moving player. Forced can also be used to describe a sequence of moves for which the player has no viable alternative, for example "the forced win of a piece" or "a forced checkmate". In these cases the player cannot avoid the loss of a piece or checkmate, respectively.^[176] Cf. forcing move.
forced win: A win guaranteed by a series of forcing moves.
forcing move: A move that presents a threat and limits the opponent's responses.^[178] Cf. forced move.
forfeit: Refers to losing the game by breaking rules, by absence or by exceeding the time control (forfeit on time).^[179]
fork: A simultaneous attack by a single piece on two (or more) of the opponent's pieces (or other direct target, such as a mate threat). When the attacker is a knight the tactic is often specifically called a knight fork. 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 usage is rare.^[5]
Forsyth–Edwards Notation: 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.^[180]^[181] Abbr. FEN.
fortress: In endgame theory, a fortress is an impenetrable position which, if obtained by the side with a material disadvantage, may result in a draw due to the stronger side's inability to make progress.^[182]
frame: A square region of the board enclosing another region not part of the given frame, akin to a picture frame. Also referred to as a ring.^[183] The outer frame consists of the 28 squares along the edge of the board, the middle frame consists of the 20 squares just inside the outer frame, and the inner frame consists of the 12 squares just inside the middle frame.^[184] The notion of the frame may be expanded to include the center itself as the innermost frame. The mobility of pieces is closely related to the frame on which they stand. In general, a piece closer to the center has greater freedom of movement than a piece closer to the edge of the board.
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.^[185] Also called casual game and informal game.
frontier line: An imaginary line dividing the board into two halves, passing between the fourth and fifth ranks.^[186]^[187] The frontier line separates White's side of the board from Black's side. Coined by Nimzowitsch.^[188]^[189]

G

gambit: A sacrifice (usually of a pawn) used to gain an early advantage in space or time in the opening.^[5]
game clock: See chess clock.
game score: Often shortened to score. The record of a game in some form of notation, usually algebraic notation. In over-the-board tournaments, the game score is recorded on a score sheet.^[190]
gardez: [from French: gardez la reine!, "Protect the Queen!"] An announcement to the opponent that their queen is under direct attack, similar to the announcement of "check". This warning was customary until the early 20th century.^[191]
GM: An abbreviation for Grandmaster.^[192]
God: Metaphorical; a hypothetical player who always plays perfectly.^[193]
good bishop: A bishop that has greater mobility, because the player's own pawns are on squares of color opposite to that of the bishop.^[194] See also bad bishop.
Grandmaster: The highest title a chess player can attain (besides World Champion). Awarded by FIDE, the title is valid for life unless exceptional circumstances (such as cheating) occur.^[195] Abbr. GM.
grandmaster draw: A game in which the players agree to a quick draw. Originally it referred to such games between grandmasters, but the term can now refer to any such game.^[195]
Greek gift sacrifice: A typical sacrifice of a bishop by White playing Bxh7+ or by Black playing ...Bxh2+ against a castled king to initiate a mating attack. Also known as the classical bishop sacrifice.^[196]

H

half-open file: A file on which only one player has pawns.^[197] Also called semi-open file.
handicap: See odds.
hanging: [colloq.] Unprotected and exposed to capture. A hanging piece may also be said to be en prise.^[195]
hanging pawns: Two pawns of the same color on adjacent files, with no pawns of the same color on the files to either side of them.^[195]
harmony: See coordination.
Harry: A nickname for the h-pawn, sometimes occurring in the expression, "Harry the h-pawn".^[198]^[199]
hauptturnier: German word that is freely translated as "candidates tournament". In the early part of the 20th century, it was necessary for the ambitious European amateur to win a succession of prizes in small tournaments, to progress to a higher level of competition. The creation of the hauptturnier enabled the process to become more formalized, and they became a regular feature of the major German chess congresses. Winning such an event conferred the title of 'Master of the German Chess Federation', and this, in turn, could be used to gain admittance to prestigious international tournaments. Some of the best players in chess history, such as Emanuel Lasker and Siegbert Tarrasch, secured their Master titles and advanced their chess careers in this way.^[200]
heavy piece: See major piece.
hole: A square that is inside or near a player's territory that cannot be controlled by a pawn. It is a gap in a player's pawn configuration, and especially dangerous when the hole is close to the center or near the king. A knight landing on a hole may be part of an attack. An example of a hole is e4 in the Stonewall Attack.^[201]
home rank: The rank on which the pieces stand in the starting position (rank one for White; rank eight for Black).^[202] Also called back rank and first rank.
horizontal line: See rank.
Horwitz bishops: A player's light-square and dark-square bishops placed so that they occupy adjacent diagonals, creating a potent attack. Also called raking bishops, and sometimes Harrwitz bishops.^[205]^[206]
human move: A move a human would make, as opposed to the kind of move that only a computer would make.^[207]
Hutton pairing: A pairing technique invented in 1921 by George Dickson Hutton for matching teams of players in which only one game is required per player. Has been used regularly for correspondence team events and for matches between many teams conducted on one day.^[208] Also called jamboree pairing.
hypermodernism: A school of thought that prefers controlling the center with pieces from the flanks as opposed to occupying it directly with pawns. Two major proponents of hypermodernism were Réti and Nimzowitsch.^[209] See also classical.

I

IA: An abbreviation for International Arbiter.
ICCA: See International Correspondence Chess Federation.
ICCF: An abbreviation for the International Correspondence Chess Federation.^[210]
ICS: An abbreviation for Internet chess server.
IGM: An abbreviation for the older term International Grandmaster. The modern usage is Grandmaster (GM).
illegal move: A move that is not permitted by the rules of chess. An illegal move discovered during the course of a game must be corrected.^[211]
illegal position: A position in a game that is a consequence of an illegal move or an incorrect starting position; a position that is impossible to reach by any sequence of legal moves.^[211]
IM: An abbreviation for the International Master title.^[212]
imbalance: Any difference between the positions of White and Black. An imbalanced position is one where White and Black both have unique advantages. Conversely, a balanced position may be drawish.^[209]
inaccuracy: A move that is not the best, but not as bad as a blunder.^[212]
inactive: See passive.
in check: See check.
increment: Refers to the amount of time added to each player's time before each move. For instance, rapid chess might be played with "25 minutes plus 10 second per move increment", meaning that each player starts with 25 minutes on their clock, and this increments by 10 seconds after (or before) each move, usually using the Fischer Delay method.^[41] See Time control § Increment and delay methods.
Indian bishop: A fianchettoed bishop, characteristic of the Indian defenses, the King's Indian and the Queen's Indian.^[213]
Indian Defense: An opening that begins 1.d4 Nf6. Originally used to describe queen's pawn defenses involving the fianchetto of one or both black bishops; now used to describe all Black defenses after 1.d4 Nf6 that do not transpose into the Queen's Gambit.^[214]
informal game: See friendly game.
initiative: The ability to make attacking moves, and force the course of play. It is an aspect of time. The attacking player has the initiative, and the defending player attempts to seize it.^[215]
innovation: A synonym for theoretical novelty.
insufficient material: An endgame scenario in which all pawns have been captured, and one side has only its king remaining while the other has only its king, a king plus a knight, or a king plus a bishop. A king plus bishop versus a king plus bishop with the bishops on the same color is also a draw, since neither side can checkmate, regardless of play. Situations where checkmate is possible only if the inferior side blunders are covered by the fifty-move rule.^[216] See Draw (chess) § Draws in all games.
interference: The interruption of the line or diagonal between an attacked piece and its defender by interposing a piece.^[215]
intermediate move: See zwischenzug.
intermezzo: 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. Abbr. IA.
International Correspondence Chess Federation: The International Correspondence Chess Federation (abbr. ICCF) was founded in 1951 to replace the International Correspondence Chess Association (ICCA).^[210]
International Grandmaster: Abbr. IGM. The original name of the FIDE title, now simply called Grandmaster (GM).
International Master: A chess title that ranks below Grandmaster but above FIDE Master. Abbr. IM.
International Woman Master: Obsolete name for Woman International Master.
Internet chess server: An external server that provides the facility to play, discuss, and view chess over the Internet. Abbr. ICS.
interpose: To move a piece between an attacking piece and its target, blocking the line or diagonal of attack. Interposing is not possible if the attacker is a knight, king, or pawn, thus only possible in case of attacking rooks, bishops, or queens. Interposing a piece is one of the three possible responses to a check.^[5]
Interzonal tournament: A tournament organised by the FIDE starting from the 1950s to 1993. It was the second qualifying cycle of the World Chess Championship. The participants were selected from the top players of the Zonal tournaments. The top ranking players qualified for the Candidates Tournament. Since 1998 the winners of the zonal tournaments have played short matches against each other over a few weeks in a knockout-style competition to determine who is eligible for the Candidates Tournament.
IQP: An abbreviation for isolated queen pawn. See isolani.
irregular opening: Early 19th-century chess literature classified all openings that did not begin with either 1.e4 e5 or 1.d4 d5 as "irregular". As opening theory developed and many openings previously considered "irregular" became standard (e.g. the Sicilian Defense), the term gradually became less common. Opening books today are more likely to describe debuts such as 1.b4 (the Sokolsky Opening) as "uncommon" or "unorthodox".^[217]
isolani: Refers to a d-pawn with no pawns of the same color on the adjacent c-file and e-file, and is a synonym for isolated queen pawn. Aron Nimzowitsch, who coined the term, regarded the isolani as a weapon of attack in the middlegame but an endgame weakness; he saw the problem of hanging pawns as related.^[218] See also Pawn structure § Queen's Gambit – Isolani.
isolated pawn: A pawn with no pawn of the same color on an adjacent file.^[219]
isolated queen pawn: Or isolated queen's pawn. Abbr. IQP. See isolani.
Italian bishop: A white bishop developed to c4 or a black bishop developed to c5. A bishop so developed is characteristic of the Italian Game. In the Giuoco Piano both players have Italian bishops. The Italian bishop stands in contrast to the Spanish bishop on b5 characteristic of the Ruy Lopez. "Italian" may be used as an adjective for an opening where one or both players have Italian bishops.^[220]

J

j'adoube: (from French, "I adjust", pronounced [ʒa.dub]) The international signal of the intention to adjust the position of a piece on the board. When playing with the touch-move rule, a player must say this in order to be able to touch a piece without being subject to the touched piece rule. The verb adouber, literally "to dub" (raise to the knighthood), is rarely used in contemporary French outside of this context. A local language equivalent, e.g. "I am adjusting", is generally also acceptable.^[5]

K

K: Symbol used for the king when recording chess moves in English.^[22]
key square: 1. An important square.; 2. In pawn endings, a square whose occupation by one side's king guarantees the achievement of a certain goal, such as the promotion of a pawn or the win of a pawn.^[216]
KGA: The King's Gambit Accepted opening.
KGD: The King's Gambit Declined opening.
KIA: The King's Indian Attack 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 serious breach of chess etiquette.^[221]
kick: Attacking a piece, often a knight, with a pawn, so that it will move. Kicking a piece may lead to gaining a tempo, or may force the opponent to concede control of key squares.^[221]
KID: The King's Indian Defense opening.
king: The most important piece in chess. It may move to any adjacent square, and it may castle. A king threatened with capture is in check; a player cannot end their move with their king in check. If a player's king is in check and there is no escape, then the king is in checkmate, and the player loses. If the player whose turn it is has no legal moves and their king is not in check, then it is stalemate, and the game is drawn.
king bishop: Or king's bishop. The bishop that is on the kingside at the start of the game. Sometimes abbreviated "KB".^[83]
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.^[222] Also called king chase.
king knight: Or king's knight. The knight that is on the kingside at the start of the game. Sometimes abbreviated "KN".^[83]
king pawn: Or king's 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.^[83]
king pawn opening: Or king's pawn opening. An opening that begins 1.e4.
king rook: Or king's rook. The rook that is on the kingside at the start of the game. Sometimes abbreviated "KR".^[83]
kingside: Or king's side. The side of the board (half-board) the kings are on at the start of the game (the e- through h-file), as opposed to the queenside.^[35] Also called king's wing.
king walk: A consecutive series of king moves designed to bring the king to a safer square. For example, if a player has castled kingside but the opponent has sacrificed a piece to destroy the kingside pawn cover, they may choose to walk the king over to the queenside to shelter behind the queenside pawns.^[223] See also King walk.
knight: A piece that may move to any nearest square not on a rank, file, or diagonal on which it stands. In other words, it may move two squares horizontally or vertically and then one square perpendicular to that (forming an L shape), jumping over any pieces in the way.
knight pawn: Or knight's pawn. A pawn on the knight's file, i.e. the b-file or g-file. Sometimes abbreviated "NP".^[83]
knight's tour: A puzzle that challenges a person to set a knight on an empty chessboard, and make the piece move around (as it moves in a chess game), but to visit every square only once. The knight's tour is the best known of a variety of tours and puzzles based on chess pieces. A closed tour (also known as a re-entrant tour) ends on the same square on which it began and needs 64 moves. An open tour ends on a different square and needs only 63 moves.^[224]
knockout tournament: See Single-elimination 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. round-robin tournament and Swiss tournament.
Kotov syndrome: This phenomenon, described by Alexander Kotov in his 1971 book Think Like a Grandmaster, 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 that they have hardly thought about at all, and it may not be a good move for that reason.^[225]
Kriegspiel: [from German, "war game"] Kriegspiel is a chess variant played by two opponents who can see only their own board, and one monitoring umpire who makes the moves of both players on a neutral board. It requires three chess sets and boards. The players make their moves based on limited information from the umpire. It was introduced in 1898. It is sometimes referred to as blind chess, not to be confused with blindfold chess.^[226]
Kt: The symbol sometimes used for the knight when recording chess moves in descriptive notation, mainly in older literature. An N is used instead in algebraic notation and in later descriptive notation to avoid confusion with K, the symbol for the king.^[22]

L

last rank: See eighth rank.
laws of chess: The rules of chess.

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