“M” Backgammon Terms

[Listed by Paul Magriel in his book Backgammon.]  Six criteria for determining whether a situation requires a safe play or a bold play. They are: (a) opponent's home board strength; (b) presence of an anchor in opponent's home board; (c) your home board strength; (d) blots in opponent's home board; (e) number of checkers you have back; and (f) number of checkers opponent has back. Criteria (a) and (f) call for making a safe play; the others point towards making a bold play.

Main flight.

In an elimination tournament, the group in which players start and compete in until they lose, and which offers the largest prize.  Compare: Consolation Flight.

Moving one of your two runners from the opponent's one-point to the opponent's four-point or five-point.   Compare: Minor Split.

To place two checkers together on one point (1) so they form a block or an anchor. Your opponent may not land or touch down on that point as long as the two checkers remain there.

To close all the points (1) in your home board.

Checker.

An optional chouette rule which says: when only one player accepts box's initial double, that player must also beaver; otherwise, he must refuse the double along with everyone else. See post by Roland Scheicher.  Compare: Mandatory Extras (1).

A game in match play where the doubling cube has reached a high-enough level that it represents sufficient points (4) for the leader to win the match; the trailer has nothing to lose by doubling at this point. This includes any post-Crawford game, where the trailing player should double at his first opportunity.

An optional rule for chouette play which says when only one player on the team accepts the box's initial double that player is obliged to accept an extra 2-cube from any other team member that wishes to pay him one point (4). See posts by Daniel Murphy and Toni Wuersch.

An optional rule for money play which says whenever a double is offered and accepted the doubler has the right to give his opponent an extra cube at the same level accompanied by a payment equal to one half of its value. The receiver of an extra now has two cubes which he may use together or separately for making future doubles. See post by Albert Steg.

In post-Crawford match play, if the leader is offered a double when the trailing player has an odd number of points (4) to go, the leader should almost always accept the double. For example, as leader against an opponent who is 5-away, taking and losing two points means the opponent still needs two games (or one gammon) to win the match.

See: Box.

The player on roll has two checkers on each of his lower three home board points, and three checkers on each of upper three home board points. The opponent has one checker on the bar, six checkers borne off, and the remainder on his one-point and two-point. Should the player double? Should his opponent accept the double?

An opportunity to offer a double while it will be accepted by the opponent.

[By analogy to market loser.]  A sequence of two rolls (one for you and one for your opponent) which takes a game from a position in which your opponent would refuse a double to a position in which your opponent would accept a double.

A sequence of two rolls (one for you and one for your opponent) which takes a game from a position in which your opponent would accept a double to a position in which your opponent would refuse a double. Knowing the number and size of your market losers is an important consideration in whether or not to double.

Market loser.

A series of games between two players which ends when one player acquires a predetermined number of points. Traditionally, matches are played to an odd number of points (3, 5, 7, etc.).  See: Match Play.

A player's probability of winning a match from a given score.

The value of a position in the context of the current match score and cube level, usually given in terms of match winning chances.

A chart showing the probability of winning a match from various scores.  Example: The Woolsey-Heinrich match equity table. Match equity tables are laid out according to the number of points each player still needs to win the match. The first column and row represent the Crawford game.