anticipatory: an effect implemented in anticipation of a subsequent event

anti-critical: a move which prevents a subsequent line-closing

battery: the alignment of a line-piece and another same-colored unit, aimed at a target (usually a King)

bi-valve: a move which opens one line and closes another

composer: one who creates chess compositions

composition: a puzzle which uses a chessboard and chess pieces, with stated stipulation(s)

cook: an unintended solution or sequence which spoils a problem

correction: a specific move by piece X which eliminates the 'general error' of a random move by X

critical: a move which allows a subsequent line-closing

cycle: three or more effects or elements which repeat in cyclic fashion over multiple solutions (or lines of play)

cyclic play: multiple solutions (or lines of play) showing a cycle

dual: a defect that allows more than one defense or continuation in a thematic line of play

dual-avoidance: the effect of forcing a specific reply or continuation

FIDE: Federation Internationale Des Echecs, the World Chess Federation

FIDE Album: FIDE's volumes containing the best problems published in a given 3-year period

formal tourney: a composing tourney in which the judge does not know the participants' names

judge: one who evaluates and honors problems submitted for a formal or informal tourney

informal tourney: a composing tourney in which the judges knows the participants' names

key or key-move: the initial move in a problem's solution

key-piece: the unit which makes the key-move

line: a consecutive array of diagonally or orthogonally adjacent squares

line-closing: the effect of closing a line

line-opening: the effect of opening a line

line-piece: a unit which guards a line (or lines), typically a Queen, Rook or Bishop

Meredith: a chess problem which contains 12 units or less (counting Kings)

miniature: a chess problem which contains 7 units or less (counting Kings)

pin: the effect of a line-piece that prevents an opposing unit from moving due to a subsequent exposed check

pinner: a unit enforcing a pin on an opposing unit

post-key: the play which occurs after the key-move

problem: see composition

promotion: the changing of a Pawn to a Queen, Rook, Bishop or Knight upon reaching the 1st or 8th rank

random move: a move by unit X which creates a 'general error'

reciprocal: two effects or elements which occur in opposing fashion in two solutions (or lines of play)

sacrifice: the offering of a unit to the opposing side to achieve an objective

set/play: a solution or continuation which exists if the side on-move could simply "pass" on his first move

solution: that which solves a chess problem

solver: one who solves (and/or cooks) chess problems

task: a record achievement of a specific theme, strategy, pattern, or combination thereof

try: in a direct-, self- or reflex-genres: a move which fails to exactly one defense; in help-genres: an intended solution which fails

underpromotion: the changing of a Pawn to a Rook, Bishop or Knight upon reaching the 1st or 8th rank

unpin: a move which eliminates a pin

waiter or waiting move: a move by one side which invokes zugzwang on the opposing side

WCCI: World Championship in Composition for Individuals, a FIDE informal tourney honoring the best problems published within a given 3-year period

WCCT: World Chess Composition Tournament, a FIDE formal tourney in which countries compete as teams

zugzwang: the compulsion of one side to move, creating a weakness exploitable by the other

Albino: the effect of a white Pawn, on the 2nd rank, moving to all four of its initially available arrival squares

AUW: short for "Allumwandlung", referring to the existence of promotions to Queen, Rook, Bishop and Knight

Babson or BabsonTask: respective promotions to Q/R/B/S, on one square, in reply to Q/R/B/S promotions (by the opposing side) on one square

Bristol: a move by line-piece X which clears the way for a subsequent move by line-piece Y in the same direction

Ceriani-Frolkin: in a proofgame, a promoted piece is captured

Circe: a fairy condition where a piece, when captured, is reborn on its game-array square; see the magazine for a more complete definition!

Grasshopper: a unit which moves along Queen-lines, but must hurdle over another unit to the square immediately beyond

Grimshaw: the mutual interference of a Rook and Bishop (of the same color) upon their arrival on a given square

Hannelius: in a twomover, the following pattern: 1.X?(2.A#)1...a!; 1.Y?(2.B#)1...b!; 1.Z!(~) 1...a 2.B#, 1...b 2.A#

Illegal Cluster: a position which is illegal, but becomes legal upon removal of a single unit (Kings excluded)

Kniest: in help-genres, the removal of a black unit (usually a Pawn) to allow subsequent mate of the black King on that square

Leo: a Chinese Queen which moves like a normal Queen but captures like a Lion

Lewmann Defense: in a twomover, an anticipatory line closing used to to defend against the threat

Lion: a unit which moves and captures like a Grasshopper, but its arrival square may be any number of squares beyond the hurdle, provided the line is free

Moose: a unit which hurdles like a Grasshopper, but turns 45 degrees upon passing over its hurdle

Nowotny (Novotny): the simultaneous interference of both a Rook and Bishop (of the same color) by an opposing unit

ODT: Orthogonal/Diagonal Transformation, the transference of orthogonal moves/functions in one line to diagonal in another line, and vice versa

Pao: a Chinese Rook which moves like a normal Rook but captures like a Lion, on orthogonal lines only

Pronkin: in a proofgame, a promoted piece returns to a homesquare for that type of unit

Zilahi: in help-genres, the reciprocal or cyclic relation of sacrificed (or captures) units and mating units