Chess glossary

The piece the whole game is about. It steps one square in any direction, can never move into check, and can never be captured — the game ends when it has no legal escape.

The strongest piece: it moves any distance along a rank, a file or a diagonal. Worth roughly nine pawns.

Moves any distance along a rank or a file. Worth roughly five pawns, and strongest on open files and the seventh rank.

Moves any distance along a diagonal, so it never leaves the colour of square it starts on. Worth roughly three pawns.

Moves in an L — two squares one way, one square across — and is the only piece that jumps over others. Worth roughly three pawns.

Moves one square forward (two from its starting square) but captures diagonally. It cannot move backwards, which is why every pawn move is permanent.

Any of the six kinds of man on the board. In conversation, "piece" often means everything except a pawn — "I won a piece" means a knight or a bishop, not a pawn.

One of the sixty-four cells, named by its file and rank: e4, g7, a1.

The eight-by-eight grid. It is set up with a light square in each player's bottom-right corner.

A column of eight squares, named a to h from White's left.

A row of eight squares, numbered 1 to 8 from White's side.

A slanting line of same-coloured squares — the bishops' and the queen's highways.

The player who moves first, and the pieces they command.

The player who moves second.

One player's turn. A "move" in notation usually means both players' turns — 1.e4 e5 is move one.

Taking an enemy man by moving onto its square. The captured man leaves the board.

A direct attack on the king. The player in check must answer it immediately: move the king, block the line, or capture the attacker.

A check with no legal answer. The game ends at once, and the player delivering it wins.

Short for checkmate.

The player to move has no legal move and is not in check. The game is a draw, however much material either side has — which is why a winning position still needs care.

A game that ends level: by stalemate, agreement, threefold repetition, the fifty-move rule, or insufficient material.

To concede the game rather than play a lost position out.

The one move that shifts two pieces: the king steps two squares towards a rook and that rook jumps to the far side of it. Legal only if neither piece has moved, the squares between are empty, and the king is not in check or passing through one.

Castling towards the h-file, written O-O. The short, common one.

Castling towards the a-file, written O-O-O. Three squares must be clear instead of two.

What happens when a pawn reaches the far rank: it becomes a queen, rook, bishop or knight of its own colour. The choice is the player's, and it is not limited to pieces already captured.

Practise it: 12 positions

To carry out a promotion.

A pawn that has just advanced two squares may be captured, on the very next move only, by an enemy pawn beside it — as if it had advanced one.

One move that attacks two targets at once. Knights fork most often, but every piece can.

Practise it: 12 positions

A piece that cannot move without exposing something more valuable behind it. A pin against the king is absolute — moving is illegal, not just costly.

Practise it: 12 positions

The reverse of a pin: the valuable piece is in front and must move, so the one behind it falls.

Practise it: 12 positions

Moving one piece so that the piece behind it attacks along the opened line. The moving piece can create a second threat of its own.

Practise it: 12 positions

A discovered attack where the opened line gives check.

Check from two pieces at once, produced by a discovery. It cannot be blocked or answered by a capture — the king must move.

A player's own first rank, where the king usually sits after castling.

Mate delivered by a rook or queen on the back rank, against a king shut in by its own unmoved pawns.

Practise it: 12 positions

A square the king can legally move to. Making one — often by pushing a pawn in front of a castled king — is the standard cure for a back-rank weakness.

A piece with no defender. Loose pieces are what tactics feed on.

A loose piece that is also attacked, and can simply be taken.

Practise it: 12 positions

Guarded by another of your men, so a capture can be answered by a recapture.

Not guarded by anything.

To threaten to capture something, or a sustained campaign against a target such as the enemy king.

Something you intend to do next move that your opponent has to answer.

To guard a man or a square, or to answer a threat.

A move that throws away material or the game — usually by missing a one-move tactic rather than by deep miscalculation.

Giving up material on purpose for something worth more: an attack, a promotion, a mating net.

Practise it: 12 positions

Exchanging a man for one of similar value.

A trade. "The exchange" specifically means a rook for a knight or bishop — winning the exchange is winning a rook for a minor piece.

The total value of the men you have. Counting it before and after a capture is the habit that prevents most blunders.

The bishop sacrifice on h7 (h2 against White) against a castled king: Bxh7+, then a knight to g5 with check and the queen to the h-file. It needs all three pieces ready and h7 left with no defender — and even then, the king stepping out to g6 has to be answered.

Both bishops given up, one on h7 and one on g7, to strip the pawns from in front of a castled king. The queen checks in between, and a rook swinging to the h-file is what turns the attack into a win; without the rook it is only a draw.

A series of checks the other king can never escape. Neither side can make progress, so the game is drawn — the usual way to save a game when you are behind in material.

Promoting a pawn to a rook, bishop or knight instead of a queen. It is right when a queen would leave the opponent stalemated, or when a knight gives a check that a queen could not.

A rook and a bishop taking turns to give check. The rook checks, the king steps aside, and the rook moves off along the line — taking a piece as it goes — to uncover a discovered check from the bishop; then it comes back and checks again. The king can only shuffle between two squares while the rook collects material. Torre–Lasker, Moscow 1925, is the famous example.

A defender with two jobs. When one piece guards two things at once, strike at one of them: if the defender answers, the other is left unguarded; if it does not, you keep what you took. The overloaded piece can be anything, even a pawn.

Mate by two bishops on crossing diagonals against a king boxed in by its own pieces — classically a king on c8, checked from a6 while the other bishop, on f4, covers b8 and c7. A queen sacrifice usually opens the way. Named after Samuel Boden, who mated this way in 1853.

Bringing pieces off their starting squares to squares where they do something. The opening is largely a race to develop.

The four central squares, and the wider zone around them. Pieces in the centre reach more squares, so control of it decides most openings.

The first phase, roughly the first ten to fifteen moves: develop, take space in the centre, get the king safe.

A defence to 1.d4 in which Black plays …Nf6, …g6, …Bg7 and …d6 and castles, letting White build a broad pawn centre in order to strike at it later with …e5 or …c5. The games are often sharp, with each side attacking on a different wing.

The King's Indian line with 5.f3: 1.d4 Nf6 2.c4 g6 3.Nc3 Bg7 4.e4 d6 5.f3. The f-pawn props up e4 and keeps Black's knight off g4; White usually goes on with Be3 and Qd2, and often castles queenside and throws the kingside pawns forward. Named after the German master Friedrich Sämisch.

The phase after development, where plans and tactics decide the game.

The phase where few pieces remain, the king becomes an attacker, and pawns become the point.

Kings facing each other with one square between them. The player who does not have to move controls the squares beyond — often the whole point of a pawn ending.

A pawn with no enemy pawn in front of it on its file or the files beside it. Nothing can stop it except pieces.

One move's worth of time. Gaining a tempo means making a threat that also advances your plan; losing one means moving the same piece twice for nothing.

A position where every legal move makes things worse, and the obligation to move is itself the problem. Almost always an endgame idea.

How exposed your king is. It is the one factor that outranks material, because losing the king ends the game.

A position that should be won with correct play. It is not a won game — stalemate, a back-rank mate or a single blunder can still take it away.

A d-pawn with no pawn of its own colour on the c- or e-file. No pawn can ever defend it, which is its weakness; in return its owner gets open lines and a knight outpost on e5 (e4 for Black). Often written IQP.

Putting a piece — best of all a knight — on the square directly in front of an enemy pawn, so that it cannot advance. It is the first step of the plan against an isolated pawn: blockade, trade pieces, then win the pawn.

The winning position in rook and pawn against rook: your pawn — any but a rook's pawn — is on the seventh rank, your king stands in front of it on the queening square, and the defending king is cut off from the pawn. The win is by building a bridge.

The winning method in the Lucena position. The rook goes to the fourth rank, the king walks out from in front of the pawn under the checks, and the rook blocks the last check — the rook is the bridge the king shelters behind.

The drawing defence in rook and pawn against rook: the defending king stands in front of the pawn and its rook holds its own third rank, so the attacking king cannot come forward. When the pawn steps onto that rank, the rook goes to the far end of the board and checks from behind.

Checking a king with a rook from the far end of the board, behind the king and its pawn. From that distance the king cannot chase the rook away without leaving its pawn, so the checks do not stop.

A way to see at a glance whether a king can catch a passed pawn. Picture the square whose side runs from the pawn to its queening square: if the king can step into that square, it catches the pawn; if it cannot, the pawn queens. A pawn still on its starting square counts as one step further on, because it can move two.

A king walking along a diagonal toward two goals at once — catching the enemy pawn and supporting its own. The opponent can stop only one of them, which is how a king that looks hopelessly far away still makes a draw.

A composed position with a stated task — win or draw — and one precise way to do it. Studies are built to show a single idea in its purest form; the Réti and Saavedra positions are two famous ones.

Squares that win a king-and-pawn ending on arrival: once the attacking king stands on one, with its pawn safe, the pawn queens whoever is to move. For a pawn on its fourth rank or lower they are the three squares two ranks in front of it — d6, e6 and f6 for a pawn on e4. A rook's pawn is different: if the defending king reaches the corner in front of it, the game is a draw.

The opposition taken from further away: the kings stand on the same file or rank with three or five squares between them, and the other side is to move. Whoever holds it can keep it as the kings come closer, until it becomes the ordinary opposition.

Getting past a king that blocks the way by going round it instead of straight at it: the attacking king steps to the side and comes forward on the far side of the defending king, shouldering it away from the pawn's path. The opposition stops a king from coming straight on; outflanking is how it gets past.

A position in which whoever is to move is worse off — each side would rather pass, and neither may. The fight is about arriving there with the opponent to move: directly, or by losing a move with triangulation. Also called reciprocal zugzwang.

The simplest mutual zugzwang: two pawns blocking each other, and each king attacking the other's pawn while guarding its own. Neither king can take, so whoever is to move has to step away, loses the pawn and, as a rule, the game.

Losing a move on purpose with the king. It walks round three squares of a triangle and comes back to where it started, while the opposing king, with only two squares to shuttle between, cannot do the same — so the same position returns with the other side to move. It is how to win a mutual zugzwang that you reached one move too early.

Squares a king must not be the first to step on. They come in pairs, one for each king, that make a mutual zugzwang: when one king steps onto its square, the other answers on the matching one, and the side that stepped first is in zugzwang.

Pairs of squares that belong together in a king ending: whenever the attacking king steps onto one, the defending king has to answer on its partner, or lose. The opposition is the simplest case.

A pawn on the a- or h-file. It queens in a corner, and a defending king that gets into that corner cannot be driven out, so endings that win with any other pawn are often only a draw with a rook's pawn. Against a queen, a rook's pawn on the seventh draws by stalemate unless the attacking king is close.

A pawn on the c- or f-file. Like a rook's pawn, a bishop's pawn on the seventh can hold against a queen: the defending king hides in the nearest corner and leaves the pawn to be taken, because taking it would be stalemate. The queen cannot win alone; the attacking king has to be close.

A pawn on the b- or g-file. Against a queen, a knight's pawn on the seventh loses just as a centre pawn does: there is no stalemate corner for the defending king, so the queen keeps forcing it in front of the pawn while the attacking king walks up.

A drawing defence in rook and pawn against rook, for a rook's pawn on the sixth rank with the attacking rook in front of it: the defending rook attacks the pawn from the side, along the sixth rank, so the attacking rook is tied to guarding it, and the defending king waits on g7 or h7 (b7 or a7 against an h-pawn).

The scan to run before every move: your checks, your captures, your threats — and then your opponent's. Lesson 4 is built on it.

A move worth calculating. Listing two or three candidates before calculating any of them is how strong players avoid tunnel vision.

The rectangle a rook and king shrink around a lone enemy king. Each check makes the box smaller until there is no room left — the method in the rook-mate lesson.

Mate with two rooks (or a rook and queen) checking alternately along successive ranks, driving the king to the edge. Also called the staircase.

Mating a lone king with king and queen. The queen takes squares away, the king walks up, and stalemate is the only real danger.

Mating a lone king with king and rook. Slower than the queen mate, and it needs both pieces working together.