Chess words, plainly explained

Chess Glossary

Chess has a vocabulary of its own, borrowed from Persian, French, German and Italian over many centuries. This glossary explains the words you are most likely to meet, in a sentence or two each, grouped by the part of the game they belong to. Where a position makes the idea clearer, the term comes with a small board.

The board and the pieces

File: A column of squares running from one player’s side of the board to the other. The eight files are lettered a to h.

The marked squares make up the e-file.
Rank: A row of squares running across the board. The eight ranks are numbered 1 to 8, starting from White’s side.

The marked squares make up the fourth rank.
Diagonal: A slanting line of squares of one color. Bishops move only along diagonals.

The bishop on c1 can travel along the diagonal from c1 to h6.
Center: The four squares in the middle of the board: d4, e4, d5 and e5. Pieces placed on or near them reach more of the board.

The four center squares: d4, e4, d5 and e5.
Kingside: The half of the board where the kings start: the e, f, g and h files.

The kingside is the half of the board from the e-file to the h-file, where the kings start.
Queenside: The half of the board where the queens start: the a, b, c and d files.

The queenside is the half of the board from the a-file to the d-file, where the queens start.
Back rank: The rank a player’s pieces start on: the first rank for White and the eighth for Black.
Minor piece: A bishop or a knight. Each is worth about three pawns.
Major piece: A rook or a queen. Major pieces are also called heavy pieces.
Material: The pieces and pawns a player has. Being “up material” means having more, counted by the usual values: pawn 1, knight 3, bishop 3, rook 5, queen 9.
The exchange: The difference between a rook and a minor piece. Winning a rook for a bishop or knight is “winning the exchange”.
Bishop pair: Both of a player’s bishops, one on each color of square. Together they cover the whole board and are often a small advantage in open positions.

Moves and rules

Capture: Moving a piece onto a square occupied by an enemy piece, which is removed from the board.
Castling: A single move of the king and a rook together: the king goes two squares toward the rook, and the rook hops to the square the king crossed. It is allowed only if neither piece has moved, the squares between them are empty, and the king is not in check and does not cross or land on an attacked square.

Castling kingside: the king goes from e1 to g1, and the rook from h1 to f1.
En passant: French for “in passing”. When a pawn advances two squares and lands beside an enemy pawn, that pawn may capture it on the very next move as if it had advanced only one square.

Black’s pawn has just moved from d7 to d5. White’s pawn on e5 may capture it by moving to d6.
Promotion: When a pawn reaches the far rank it is replaced by a queen, rook, bishop or knight of the same color. Choosing anything other than a queen is called underpromotion.

The pawn moves to e8 and is exchanged for a queen, rook, bishop or knight.
Check: An attack on the king. The player in check must end it at once by moving the king, blocking the attack or capturing the attacker.

The rook on e1 attacks the king on e8. Black is in check.
Checkmate: A check that cannot be escaped. It ends the game, and the player giving it wins. Often shortened to “mate”.

The queen gives check, the white king protects her, and the black king has no safe square. Checkmate.
Stalemate: A position where the player to move is not in check but has no legal move. The game is a draw.

Black is to move and is not in check, but every square beside the king is covered. Stalemate.
Draw: A game with no winner. Draws come about by stalemate, agreement, repetition, the 50-move rule or insufficient material.
Threefold repetition: A player may claim a draw when the same position, with the same player to move and the same moves available, occurs for the third time.
50-move rule: A player may claim a draw when 50 moves by each side have passed with no capture and no pawn move.
Insufficient material: A draw because neither side has enough pieces left to give checkmate, such as king against king, or king and one minor piece against king.

King and bishop against king. No checkmate is possible, so the game is a draw.
Perpetual check: A series of checks the other player cannot escape. It leads to a draw, in practice by threefold repetition.
Resign: To concede the game before checkmate. Players usually resign when the loss is certain.
Touch-move: The over-the-board rule that a player who deliberately touches a piece must move it if it has a legal move.
Algebraic notation: The standard way to write down moves. Each square is named by its file and rank, and a move is written as the piece’s letter and the square it goes to: Nf3 means a knight moves to f3, and e4 means a pawn moves to e4.

This knight move is written Nf3: N for knight, f3 for the square it lands on.

Tactics

Tactic: A short sequence of moves that wins material or gives checkmate by force.
Combination: A forcing series of moves, often starting with a sacrifice, that ends in a clear gain.
Fork: One piece attacking two or more enemy pieces at the same time, so that only one can be saved.

The knight jumps to c7, where it checks the king and attacks the rook at the same time.
Pin: An attack on a piece that cannot move without exposing a more valuable piece behind it. If the piece behind is the king, the pinned piece may not legally move at all.

The bishop pins the knight on f6. If the knight moves, the queen on d8 is captured.
Skewer: An attack on a valuable piece that must move away, exposing a second piece behind it to capture.

The rook checks the king on e5. Once the king leaves the rank, the rook takes the queen on b5.
Discovered attack: An attack opened up when one piece moves out of the way of another. If the uncovered piece attacks the king, it is a discovered check.

The knight jumps to e6 with check and uncovers the bishop’s attack on the rook at h8. Black must answer the check, and the rook is lost.
Double check: A check from two pieces at once, which happens when a piece gives check as it uncovers a second check. The only answer is to move the king.

The knight moves to f6 and gives check, and the rook behind it gives check as well. The king has to move.
Hanging piece: A piece that is attacked and not defended, so it can be captured for free. Also said of any undefended piece.
En prise: French for “in a position to be taken”: said of a piece that is left where it can be captured.
Sacrifice: Giving up material on purpose to gain something else, such as an attack on the king.
Removing the defender: Capturing or driving away a piece that protects something important, so that what it protected can be taken.
Deflection: Forcing a defending piece to leave the square or line it needs to guard.
Decoy: Luring an enemy piece, often the king or queen, onto a square where it can be attacked.
Overloaded piece: A piece with two defensive jobs that cannot do both at once.
Back-rank mate: Checkmate by a rook or queen on the back rank against a king hemmed in by its own pawns.

The rook gives check along the back rank, and the king’s own pawns block every escape.
Smothered mate: Checkmate by a knight against a king that is completely surrounded by its own pieces.

The knight on f7 gives checkmate. The king is walled in by its own rook and pawns.
Zwischenzug: German for “in-between move”: an unexpected move, usually a check or a threat, played before the expected recapture.
X-ray: An attack or defense that works through another piece standing on the same line.
Luft: German for “air”: an escape square for the castled king, made by advancing one of the pawns in front of it.

The pawn has moved to h3, so the king can step to h2 if it is checked on the back rank.
Blunder: A serious mistake, such as leaving a piece to be taken or overlooking a checkmate.

Strategy and pawn structure

Development: Bringing the pieces off their starting squares to squares where they are useful.
Tempo: A single move regarded as a unit of time. Making the opponent waste a move “gains a tempo”.
Initiative: The ability to make threats that the opponent has to answer. The player with the initiative decides where the game goes.
Open file: A file with no pawns on it. Rooks are strongest on open files. A file with only enemy pawns on it is half-open.

No pawns stand on the d-file, so it is open, and White’s rook controls it.
Outpost: A square in the opponent’s half that is protected by a pawn and cannot be attacked by an enemy pawn. Knights are especially strong on outposts.

The knight on d5 is protected by pawns, and no black pawn can ever attack it.
Passed pawn: A pawn with no enemy pawn in front of it on its own file or on either neighboring file, so no pawn can stop it from promoting.

No black pawn stands on the c-, d- or e-file, so nothing but pieces can stop White’s d-pawn.
Isolated pawn: A pawn with no friendly pawns on the neighboring files. It has to be defended by pieces.

White has no pawns on the c-file or e-file, so the pawn on d4 is isolated.
Doubled pawns: Two pawns of the same color on one file, usually the result of a capture. They cannot protect each other and are often a weakness.

Two white pawns stand on the c-file. Neither can protect the other.
Backward pawn: A pawn that has fallen behind the pawns beside it and cannot safely advance to join them.

The d3 pawn is backward. Its neighbors have gone ahead, and if it steps to d4 a black pawn captures it.
Pawn chain: A diagonal line of pawns in which each one protects the pawn in front of it.

A pawn chain from b2 to e5. Each pawn protects the one in front of it.
Pawn structure: The arrangement of the pawns. Because pawns cannot move backward, the structure changes slowly and shapes each side’s plans.
Good and bad bishop: A bishop is “bad” when its own pawns stand on squares of its color and block it, and “good” when they do not.

White’s bishop is hemmed in by its own pawns on c4 and e4, which stand on squares of its color. It is a bad bishop.
Weak square: A square that can no longer be defended by a pawn, where an enemy piece can settle.
Space: The room a player’s pieces have to move in, usually the squares behind that player’s advanced pawns.
Prophylaxis: A move made to prevent the opponent’s plan before it starts.
Trade: A capture answered by a recapture of equal value. Also called an exchange.

Openings

Opening: The first phase of the game, in which both sides develop their pieces. Also the name for a recognized sequence of first moves.
Gambit: An opening in which a player offers material, usually a pawn, in return for faster development or control of the center.
Fianchetto: Developing a bishop onto the long diagonal by moving the knight’s pawn one square and placing the bishop behind it, on g2 or b2 for White.

White has played the pawn to g3 and placed the bishop on g2, where it looks down the long diagonal.
Open game: An opening that begins with both players moving the king’s pawn two squares (1.e4 e5). More loosely, any position with open lines for the pieces.
Closed game: An opening that begins with both players moving the queen’s pawn two squares (1.d4 d5). More loosely, a position where locked pawns block the pieces.
Italian Game: The opening 1.e4 e5 2.Nf3 Nc6 3.Bc4, in which White’s bishop aims at the f7 pawn. One of the oldest recorded openings.

The Italian Game: White’s bishop comes to c4.
Ruy Lopez: The opening 1.e4 e5 2.Nf3 Nc6 3.Bb5, also called the Spanish Game. It is named after the 16th-century Spanish priest who analyzed it.

The Ruy Lopez: White’s bishop comes to b5 and puts pressure on the knight.
Sicilian Defense: The reply 1…c5 to 1.e4. Black fights for the center from the side and gets an unbalanced game.

The Sicilian Defense: Black answers 1.e4 with the c-pawn.
French Defense: The reply 1…e6 to 1.e4, followed by …d5. Black accepts a cramped position in return for a solid pawn chain.

The French Defense: the pawn on e6 supports the advance to d5.
Caro-Kann Defense: The reply 1…c6 to 1.e4, followed by …d5. It is similar in spirit to the French but keeps the light-squared bishop free.

The Caro-Kann Defense: the pawn on c6 supports the advance to d5.
Queen’s Gambit: The opening 1.d4 d5 2.c4. White offers a wing pawn to pull Black’s pawn away from the center.

The Queen’s Gambit: White offers the pawn on c4.
King’s Indian Defense: A defense to 1.d4 in which Black plays …Nf6, …g6 and …Bg7, lets White build a pawn center, and attacks it later.

The King’s Indian Defense: Black’s bishop sits on g7 while White takes the center.
Scholar’s Mate: A four-move checkmate on f7 with queen and bishop. It only works if the defender does not see it coming.

Scholar’s Mate: the queen has captured on f7, protected by the bishop, and it is checkmate.
Transposition: Reaching a known position by a different order of moves.

Endgames

Endgame: The last phase of the game, when few pieces remain and the kings can take an active part.
Middlegame: The phase between the opening and the endgame, when most pieces are developed and the main plans are carried out.
Opposition: Two kings facing each other with one square between them. The player who does not have to move “has the opposition”, because the other king must give way.

The kings face each other with one square between them. Whoever has to move must give way.
Zugzwang: German for “compulsion to move”: a position in which every available move makes the player’s own position worse.

Black to move is in zugzwang: any king move lets the pawn through. If Black could pass, the game would be a draw.
Rule of the square: A quick way to see whether a king can catch a passed pawn: picture a square reaching from the pawn to its promotion rank. If the king can step inside it, the pawn is caught.

The marked squares are the corners of the pawn’s square. The black king is inside it, so it catches the pawn.
Key squares: Squares which, once occupied by the attacking king, guarantee that a pawn will promote.

For a pawn on e4 the key squares are d6, e6 and f6. If White’s king reaches one of them, the pawn will promote.
Lucena position: A standard winning position in rook endgames: the stronger side has a pawn on the seventh rank with its king in front of it, and uses the rook as a shield against checks, a method known as building a bridge.

The Lucena position. White’s pawn is one step from promoting, and the rook will shield the king from checks.
Philidor position: A standard drawing method in rook endgames: the defender keeps the rook on its own third rank until the enemy pawn advances, then checks the king from behind.

The Philidor position. Black’s rook holds the rank in front of the white king; if the pawn advances to e6, the rook drops back to check from behind.
Opposite-colored bishops: Each side has one bishop and they travel on different colors, so they can never meet. Endgames with only these bishops are often drawn even a pawn or two down.

White’s bishop moves on light squares and Black’s on dark squares, so they can never attack each other.
Fortress: A defensive set-up that the stronger side cannot break down, despite having more material.
Tablebase: A computer database that gives the exact result, with perfect play, of every position with only a few pieces left.

Clocks and competition

Time control: The amount of thinking time each player has for the game.
Increment: Extra seconds added to a player’s clock after each move.
Flag: To run out of time. The word comes from the small flag on a mechanical clock that falls when the time is up.
Bullet: Chess with less than three minutes per player for the whole game.
Blitz: Fast chess, usually three to five minutes per player, often with a small increment.
Rapid: Chess with more than 10 minutes but less than an hour per player.
Classical: Slow chess, with an hour or more per player. World championship matches are played at classical time controls.
Elo rating: A number that measures playing strength, named after the physicist Arpad Elo. It rises after wins and falls after losses, by more when the result is a surprise.
Grandmaster: The highest title awarded by the world chess federation, held for life. It is often shortened to GM.
FIDE: The Fédération Internationale des Échecs, the international chess federation, founded in 1924. It publishes the official Laws of Chess and runs the world championship.
Simultaneous exhibition: An event in which one strong player plays many opponents at once, walking from board to board.