Activate

to develop, improve the position of, mobilize. or make more aggressive.

Active

aggressive, with regard to a move, variation or placement.

superiority in development, space, material, pawn structure, or king safety, or in any combination of these.

the process of determining through careful examination the best moves in a variation or position.

a threat to capture an enemy unit. A force aimed at a specific objective or for a definite purpose. To make moves or a series of moves to mate, gain material, or obtain advantage.

the rank occupied by all eight enemy pieces in the original position.

a pawn whose neighboring pawns are too far advanced to protect it. Usually a weakness, generally restrained by enemy units, often subject to frontal attack along the file it occupies.

A passive bishop, often obstructed by its own pawns; usually a permanent disadvantage.

a checkmate that can be forced against a lone king.

two or more pieces of like power attacking supportively along the same line.

a defensive strategy aimed at preventing the advance of an enemy pawn, especially a passed pawn, by stationing a piece directly in front of it and guarding that square with other pieces or pawns.

a meaningful error.

a viable opening move appearing in current chess literature.

when mobilizing a pawn majority, start by moving the unopposed pawn.

the four squares, e4, d4, e5, d5, taken as a block. Loosely, the surrounding squares as well.

two White pawns, on d4 and e4, or two Black pawns, on d5 and e5.

a centre blocked by both sides pawns and therefore impassable to pieces.

a file containing pawns for both players, so neither side's queens or rooks can move all the way through it.

one in which the centre is blocked by pawns, in which few, if any, exchanges have taken place.

a forced series of moves, usually involving sacrifice, always leading to an improvement of one's situation.

Connected Passed Pawns

two friendly passed pawns on adjacent files, usually occupying the same or a nearby rank.

Corral

the trapping of a knight by a bishop along the edge.

Counterattack

an attack mounted by the defender or a player who is apparently defending.

Cramped

blocked by pawns, usually on the third rank; constricted.

Critical Square

one whose occupation by the superior king insures completing a task.

Decoy

an outside passed pawn offered as a sacrifice to lure an enemy piece (usually the king) out of position.

Development

moving a piece to a better square, or improving its scope or potential by moving a pawn out of its way.

Discovery

moving a unit and thereby unveiling an attack by another friendly unit, often resulting in two attacks simultaneously; one from the moving unit and one from the stationary one. Also called a discovers attack.

Double Attack

two or more threats stemming from the same move.

Double Check

two checks given by the same; a discovery in which both the moving and stationary units give check.

Doubled Pawns

two friendly pawns occupying the same file.

Down the Exchange

having a knight or bishop against an enemy rook.

Edge

any of the board's four outside rows

Endgame

the third and final phase of a chess game, after the opening and middlegame.

En Prise

"in take." A French term designating an unprotected unit subject to capture.

Exchange

an equal trade. To trade equal amounts of material.

Exchange Values

the relative values of the pieces and pawns: a pawn is worth one, a bishop or knight three, a rook five, and a queen nine.

Family Fork

a triple knight fork to the enemy king, queen, and a rook. Also called a royal fork.

Fianchetto

a flank development of a bishop, usually to a knight-two square.

Flank

usually, the two outer rows on either side of the board, though sometimes including the adjacent bishop file.

Flank Openings

an opening in which White doesn't necessarily occupy the centre with pawns, instead relying on off-centre advances and opting to fianchetto at lest one bishop.

Fork

A tactic by which a friendly unit attacks at least two enemy unites with the same move.

Fork Trick

a combination that wins a pawn or trades centre pawns favourably. A piece is temporarily sacrificed and regained by a subsequent pawn fork.

Gambit

a voluntary sacrifice in the opening, usually of a pawn, offered to build the initiative or the attack, or to blunt your opponent's initiative or attack.

Good Bishop

a bishop unimpeded by its own pawns, usually opposing a bad bishop that is so blocked.

Half-Open File

a file, occupied by only one pawn, that the other side's major pieces can use for attack.

Hanging

simultaneously attacked and unprotected. A related term is en prise.

Heavy Piece

a major piece; either a queen or rook.

Hole

a weakness, usually a square on one's third rank, incapable of being defended by a pawn and therefore ideal for occupation by enemy pieces.

Hypermodern

a school or style advocating several ideas opposed to classical principles, such as controlling the centre initially from the flank rather than directly occupying it.

In-Between Move

a move that interrupts an apparently forced sequence. Also called a zwischenzug.

Initiative

the alit to attack and force the play.

Isolated Pawn

a pawn with no friendly pawns on adjacent files therefore incapable of being defended by a pawn.

King Safety

one of the five main elements of chess, along with time, space, pawn structure and material.

Knight's Corral

a bishop trap of a knight on the edge.

Lose a Move

create a zugzwang by transferring the same position to the other player, making it your opponent's turn to move.

Luft

an escape square for the king. When you move a pawn to create an escape square, you "make luft".

Major Piece

a queen or rook.

Maneuver

the repositioning of a piece.

Material

pieces and pawns collectively.

Mating Material

sufficient material to force mate.

Middlegame

the second phase of a chess game, after the opening and before the endgame.

Minor Pieces

Bishops and knights.

Mobility

freedom of movement.

Notation

a system to record chess moves. If you keep notation, you write down the moves of the game.

Open Centre

a centre unblocked by pawns, through which pieces can move.

Open File

a file without pawns on it.

Open Game

a game in which at least a pair of centre pawns have been exchanged, so that movement through the centre is possible.

Opening

the beginning phase of a chess game, usually lasting 10 or 15 moves.

Open Line

a rank, file, or diagonal unobstructed by pawns.

Opposition

in endgames, a zugzwang relationship between the opposing kings, in which it's disadvantageous not to be on the move.

Outpost

a weak square, incapable of being guarded by enemy pawns, supported by at least one friendly pawn, usually on the enemy;s third or fourth rank, that can be occupied by a piece to good effect.

Outside Passed Pawn

the passed pawn farthest from the main fighting area or from the two kings, often used as a decoy.

Overload

a tactic exploiting an overburdened piece's inability to fulfill all it's defensive commitments.

Overworked Piece

an overloaded piece, unable to honour it's protective commitments.

Passed Pawn

a pawn capable of advancing to promotion because no enemy pawns can block it or guard squares in its path.

Passive

refers to a move that merely guards, wards off threats, or marks time, as opposed to an active attacking or counterattacking move.

Pawn Chain

an interlocking group of friendly and enemy pawns blocking each other's movement.

Pawn-grabbing

taking risky pawns at the expense of development and position.

Pawn Island

a group of pawns separated from other friendly pawns by at least one file. A pawn island may contain one or more pawns.

Pawn Majority

a troop of friendly pawns outnumbering enemy pawns over the same number of files.

Pawn Structure

the overall configuration of pawns. One of the five elements of chess.

Pawn Weakness

a pawn that can be exploited or that can't be defended adequately by other friendly pawns.

Pin

a tactic preventing or dissuading an enemy unit from moving off a line for fear of exposing a friendly unit to capture or a key square to occupation. The pinned unit is in the unenviable situation of being a shield.

Principle

a guide for reasonable play.

Problem Bishop

a bishop generally blocked by its own pawns, resulting from a specific opening.

Protected Passed Pawn

a passed pawn defended by another pawn and generally safe from capture by enemy pieces.

Queening

promoting a pawn to a queen.

Removing the Defender

a tactic making a unit vulnerable by capturing, luring or driving away, or immobilizing its protector. Also called removing the guard or undermining.

Sacrifice

a voluntary surrender of material for attack or positional advantages.

Simplification

exchanging pieces to avoid complications, clarifying am advantage.

Skewer

the opposite of a pin. A straight-line tactic in which an enemy piece is compelled to move off the line of attack, exposing on the same line another unit to capture or a key square to occupation.

Space

one of the five main elements of chess, generally based on mobility and the number of squares influenced and controlled.

Strategy

general, long-term planning, as opposed to specific, immediate actions (tactics).

Support Mate

a checkmate given by a protected queen on a square adjacent to the enemy king.

System

a set of related opening variations branching from a particular move or group of moves, in which pieces and pawns are positioned for harmonious purposes, with corresponding logic. and in which definite middlegame plans emerge.

Tactics

short-term, immediate attacks and threats.

Tempo

a unit of chess time. The time represented by a move. Plural: tempi.

Threat

a direct or indirect attack, which must be answered.

Time

one of the main elements of chess, usually evaluated in terms of initiative and development.

Touch Move

a rule requiring the player to move the first unit touched on the player's turn.

Trade

an exchange of equal material.

Transpose

in a variation, to reverse or change the order of moves to arrive at the same position.

Trap

a baited variation to lure a careless opponent into error.

Trapped Piece

a threatened piece that can't escape attack, and therefore is lost.

Underpromotion

promoting a pawn to either a rook, a bishop, or a knight, but not the queen.

Up the Exchange

having the advantage of a rook against a minor piece.

Variation

a sequence of moves, particularly in the opening.

Waiting Move

a move that shifts the turn to the opponent without changing anything important in the position.

Weakness

a square inadequately defended, generally not capable of being guarded by pawns.

X-ray

a skewer attack or defense.

Zugzwang

a German word meaning "compulsion to move". When you are "in zugzwang", any move you make worsens your situation.

Zwischenzug

a German word meaning "intermediate move". Also called "in -between move".