Backgammon Dictionary

The random pairing of competitors in a tournament to determine who will play whom or who will get byes.

Refuse a double.

[From the server message:  Player xxx drops connection.]  A player on a backgammon server who avoids a reduction to his rating by intentionally leaving a match he is about to lose before the result recorded.

The maximum game winning chances at which it is correct for a player to refuse a double; the point at which a player is equally well off accepting a double or refusing a double; take point.

In a chouette, an agreement between two players after a double by the box that one player will accept the double, the other will refuse, and they will share their combined earnings or loss.

Double ducks.

A form of tournament play in which in which multiple pairs of competitors play with the same dice rolls in separate games and compare their results.  See: How to Play Duplicate Backgammon.

In a rollout, the use of the same sequence of random rolls with different candidate positions. The idea is that lucky rolls for one position will tend to be lucky for the other position as well, and luck will be less of a factor in the outcome. See post by David Montgomery.

See: Duplicate Backgammon.

A position in which the same number can be used constructively in more than one way. For example, when your opponent can use a 5 to hit either of two blots, his 5's are said to be duplicated. All else being equal, a position which duplicates the opponent's good numbers is better than one which does not because it means the opponent has fewer good rolls in total. See post by Simon Woodhead.

A backgammon variant in which the players start with all their checkers off the board.  See: How to Play Dutch Backgammon.

[Coined by Danny Kleinman in Double Sixes from the Bar.]  The negative impact on flexibility of having spare checkers exactly six pips apart.

The first few moves of a game, before the players have settled on a particular game plan.

A comparison of the cost of doubling slightly before opponent's drop point versus doubling slightly past opponent's drop point. This number varies depending on the score of the match, the level of the cube, and the chance of gammon in the current game. It is useful in determining how aggressively a player should double to avoid losing his market.

The open point directly in front of a prime.

The average number of rolls required to bear off all your checkers multiplied by the average pip value of a roll (49/6 pips). A player's EPC is equal to his actual pip count plus the wastage of the position. For more information, see article by Walter Trice and post by Douglas Zare. The EPC is also known as the Trice Count in honor of Walter Trice (1949–2009).

A double made at or near the point of maximum effectiveness, when the opponent would be correct to either accept or refuse.

To abandon an ace-point game to avoid losing a backgammon (2) or a gammon.

A tournament event in which half the competitors are eliminated each round until just one player remains.  Compare: Round Robin Format.

A method of rating players devised by Arpad Elo for the U.S. Chess Federation in 1960. Most backgammon ratings systems are based on Elo's method; for example, see FIBS rating formula.