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10-Percent Doubling Rule A guideline for cube handling in pure race positions. If you add 10% to your pip count, you should double if the result is not more than two pips greater than the opponent's count, and you should redouble if the result is not more than one pip greater. Your opponent should accept the double if your count plus 10% is no more than two pips less than his count. 8-9-12 Doubling Rule A guideline for cube handling in pure race positions. You should double if the opponent's pip count exceeds yours by 8% or more, and redouble if it exceeds yours by 9% or more. Your opponent should accept the double if his pip count exceeds yours by no more than 12%.

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ABT American Backgammon Tour, an annual master-point competition of participants in major U.S. tournaments.  Website: ABT. Accept a Double To agree to continue playing a game at twice the previous stakes after the opponent offers a double.  Compare: Refuse a Double. Ace A rolled die showing the number 1. Ace-Point Traditional name for the one-point. Ace-Point Game A position in the late stages of a game in which a player is anchored on the opponent's one-point trying to hit a shot as the opponent brings his checkers home and bears them off. Acey-Deucey [Also spelled "Acey-Deucy" or "Acey-Ducey".]  The roll of 1 and 2 with two dice. A backgammon variant in which the roll of 1 and 2 gives the player extra turns.  See: How to Play Acey-Deucey. Acting Captain In a chouette, the crew member who plays for the team against the box after the original captain has declined box's double and is no longer in the game. Action Play A play designed to provoke an exchange of hits, typically used after the opponent has escaped his runners. Action Position A position in which one player doubles based upon his immediate blot-hitting chances. Active Builder A checker which is completely free to make another point. Advanced Anchor An anchor on the opponent's five-point, four-point, or sometimes three-point. An made point on the opponent's five-point, four-point, or bar-point. (Many authors include the bar-point, though it is technically not an anchor, because it functions much like an advanced anchor when playing a holding-game.)  See: Holding Point. Advanced Level A player of considerable experience and skill who has moved beyond intermediate level. Ahead in the Count Having a lower pip count than your opponent; see count (2). Ahead in the Race Having a lower pip count than your opponent. Air Ball An unexpectedly poor roll, especially one that fails to hit or fails to make a point. Ammunition Checkers in position to carry out an attack, in particular, checkers in the zone. Analog Clock A traditional chess clock with hands that show the time remaining for each player. It has a flag that falls to indicate when a player's time has expired. Analog clocks generally do not have a time delay feature, making them less suitable than digital clocks for use in backgammon. Anchor A point (1) occupied by two or more of your checkers in the opponent's home board. Annotated Match A recorded match with added analysis and commentary.  Example: The annotated match between Kit Woolsey and Jeremy Bagai. Annotation Analysis and commentary about a backgammon game written after the game is played. Anti-Joker A very bad roll; the opposite of a joker. Army The formation of a player's checkers as they work together to block and attack the opponent, then and come home safely. Around the Corner A move from the opponent's outer board to the player's outer board. Asset A feature that contributes to the strength of a position, such as made points and flexibility.  Compare: Liability. Attacking Game Blitz (1). Attack Zone See: Zone of attack. Automatic Doubles An optional rule in money play: If both players throw the same number on the first roll of a game, the stakes are doubled. The doubling cube is turned to 2 and stays in the middle. Players usually agree to limit the number of automatic doubles to one per game. Automatics Automatic doubles. Awkward Number A dice roll which forces a player to leave a shot or break a valuable point (2).

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Back Game [Also spelled "backgame".]  A strategy employed by a player who is substantially behind in the race but has two or more anchors in the opponent's home board. The player holds both anchors as long as possible, forcing his opponent to bear in or bear off awkwardly. The idea is to hit a late shot and then contain the hit checker behind a prime. See posts by Daniel Murphy and Marty Storer.  Compare: Holding Game. Backgammon A game played with dice and checkers on a board consisting of twenty-four points (1), in which each player tries to move his checkers home and bear them off while preventing the opponent from doing the same thing.   See: the Rules of Backgammon. A completed game of backgammon (1) in which the losing player has not borne off any checkers and still has one or more checkers on the bar or in the winner's home board. A backgammon is also called a triple game because the winner receives three times the value of the doubling cube.  Compare: Single Game and Gammon. Backgammon Board Backgammon (1) is played on a board consisting of twenty-four narrow triangles called points (1). The triangles alternate in color and are grouped into four quadrants of six triangles each. The quadrants are referred to as a player's home board and outer board and the opponent's home board and outer board. The home and outer boards are separated from each other by a ridge down the center of the board called the bar. Backgammon Server A computer on the Internet which hosts games of backgammon (1). Competitors play in real time with opponents from around the world. The server rolls the dice, communicates the plays to each player, keeps score, and maintains ratings for all players. Some servers even let you play for money. You typically interact with a server using client software downloaded to your computer.  See: Backgammon Play Sites. Back Man Runner; a player's rearmost checker. Baffle Box A device through which dice are dropped to randomize a roll. The dice are deflected and jostled about as they fall through the box. Bakelite An early type of plastic, used in the 1920's and 1930's for the creation of backgammon playing pieces. Many people prefer the look and feel of bakelite to newer materials. See post by Albert Steg. Banana Split [Because you must be "bananas" to try it.]  To hit loose by breaking a point in your home board, thereby leaving two blots. Bankroll The amount of money you have available for betting, or the maximum amount you are willing to lose in a session.  See: Money Management. Bar The raised ridge down the center of a backgammon board dividing the home board from the outer board. Checkers are placed on the bar after they have been hit. Barabino [Named after backgammon expert Rick Barabino.]  A roll of 5-4 from the bar used to make an anchor on the opponent's five-point. Bar-Point A player's seven-point, so named because it is physically adjacent to the bar. Battle of Primes A position in which both players have checkers trapped behind an opponent's prime.   See: Prime-vs-Prime. Bear In To move a checker into your home board prior to bearing off. Bear Off To remove a checker from the board according to a roll of the dice after all of your checkers have been brought into your home board. Bearoff The last stage of the game during which checkers are borne off. Bearoff Database A computer-generated table associating each possible bearoff position with a value that represents the quality of that position. The associated value is either the equity of the position (in a two-sided database) or a distribution of the expected number of rolls to bear off (in a one-sided database). Bear On To be within six points (1) of, and therefore reachable with a single number of the dice. For example, a checker on the 13-point bears on points 12 through 7. Beaver An immediate redouble by a player who just accepted a double. A player who beavers turns the cube up one level and retains possession of the cube.  See: Beavers. Beavers A rule often used in money play (but never in match play) which says: A player who accepts a double may immediately redouble (beaver) without giving up possession of the cube. The opponent (the player who originally doubled) may refuse the beaver, in which case he resigns the game and loses the current (doubled) stakes. Otherwise, he must accept the beaver and continue the game at quadruple the stakes prior to the double. See post by Sander van Rijnswou. Behind in the Count Having a higher pip count than your opponent; see count (2). Behind in the Race Having a higher pip count than your opponent. Bertha To mistakenly play the roll of 6-5 from the opponent's one-point to your mid-point without seeing that the opponent has made his bar-point and blocks your way. BIBA British Isles Backgammon Association.  Website: BIBA. Big Play A bold or aggressive play when a safer but less constructive play is available. Binache Beaver. Blitz An all-out attack on enemy blots in your home board aimed at closing out your opponent. A quick elimination tournament consisting of short matches. Block [Noun.]  A point (1) occupied by two or more checkers held for the purpose of hindering the opponent's progress. [Verb.]  To prevent forward movement of the opponent's checkers by making points in front of them. Blockade A series of blocks arranged to prevent escape of the opponent's runners. The ideal blockade is a prime. Blocking Backgammon A backgammon variant in which one checker by itself controls a point (1).  See: How to Play Blocking Backgammon. Blocking Game A game plan where the primary strategy is to build a strong blockade. Blot A single checker sitting alone on a point (1) where it is vulnerable to being hit. Blot-Hitting Contest An exchange of loose hits in which both players try to gain a key point. Blue game A kind of collusion in a chouette. Two or more players silently agree to share their winnigs, thus if either of them is in the box and the other is captain, the captain deliberately makes bad moves or wrong doubling decisions. (From Philipp Martyn on Backgammon, p. 162.) Blunder A large checker play or cube error, especially one made out of recklessness or inattention.   Compare: Whopper. See post by Daniel Murphy. Board A backgammon board. One of the four quadrants that make up the playing area: your home board, your outer board, the opponent's home board, and the opponent's outer board. A player's home board. For example: a strong board is a home board with several made points; an n-point board is a home board with n points made; to make your board means to close all the points in your home board. Board Layout See: Starting Position. Board Setup See: Starting Position. Bold Play A play that leaves one or more blots that the opponent can easily hit.   Compare: Safe Play. Bold-Safe Criteria See: Magriel's Safe-Bold Criteria. Book a Checker Cover a blot. Bot [Contraction of "robot."]  A computer program on a backgammon server that plays and competes just as if it were a human player. Any computer program that can play backgammon (1) and analyze positions (such as Jellyfish, Snowie, or GNU Backgammon). Box [Short for "man in the box," a person in a difficult or trying position.]  The player in a chouette who plays alone against all the others. Boxcars A roll of 6-6 (double 6's). Boxes A roll of 6-6 (double 6's). Boys (The Boys) A roll of 6-6 (double 6's). Break To take apart, as in break a point, break a prime, or break one's board. Break a Point To remove a checker from a point (1) that contains only two checkers, thus leaving an open. (The opposite of make a point.) Break a Prime To open one or more points (2) in a prime. Break Contact To move past the last of the opponent's checkers, so that no further hitting or blocking is possible. The game becomes a pure race. Break One's Board To open one or more points (2) in your home board after having made your board. Broken Prime An incomplete prime with a gap in it. Bronstein Clock A chess clock with a feature that allows a time delay with each move.   See also: Fischer Clock. Builder A checker brought into your outer board where it bears directly onto one or more key points that you want to make. Build One's Board To make points in your home board. Bump Hit a checker. Bump and Pass Pick and pass. Bump and Run Pick and pass. Bury a Checker To play a checker deep within your home board where it has no value. Busted Back Game A backgame attempt that fell apart when the backgame player was forced to move checkers deep into his home board where they could no longer contain a hit checker. Button up To safety a blot by bringing it together with another checker. Bye [As in "go by".]  The position of a player in a tournament who advances to the next round without playing a match. Byes are often randomly awarded in the first round of an elimination tournament to make the number of players in the second round an exact power of 2. BYOB Acronym of "bring your own board," sometimes used in announcement of live tournaments.

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Calcutta Auction A lottery of entrants in a backgammon tournament. At the start of the tournament, players are auctioned off and the proceeds go into a pool to be distributed later to the buyers of the successful players. Sometimes players are grouped into fields, with each field sold as a package. The rules usually allow a player to buy back a portion of himself if he wants to increase his stake in the tournament. See posts by Toni Wuersch and Chuck Bower. California Rule An optional rule that says the winner of the opening roll has the option of rerolling both dice if he also turns the cube to 2. (The cube remains in the center.) See post by Peter Anderson. Candlesticks A position in which a player's checkers are piled high on a few points (1). Captain In a chouette, the leader of the team playing against the box. He rolls the dice and makes the final decisions for the team. Cash a Game To offer a double which you believe will be refused so you can collect the current value of the cube; claim a game. Cast To throw a pair of dice. Catalin An early plastic, similar to bakelite, that was popular in the 1930's and 40's in the creation of backgammon playing pieces. Catchers checkers which have been purposely spread out to maximize the chance of hitting an opposing checker if it tries to escape. Centered Cube The position of the doubling cube before either player has offered a double. A centered doubling cube is placed halfway between the players at the start of each game with the number 64 facing up (representing a value of 1). Championship Division Open division. Chase Play dangerously, especially in offering or accepting doubles, in an attempt to recover losses. Checker One of the fifteen markers, all of one color, that a player moves around the board according to rolls of the dice. Also known as men, pieces, stones, or counters. Checker Play The movement of the checkers according to numbers on the dice. The art or skill of moving the checkers.   Compare: Cube Play (2). Chequer British spelling of checker. Chess Clock Two adjacent connected clocks with buttons that stop one clock while starting the other so that the two component clocks never run simultaneously. The purpose is to keep track of the total time each player takes and ensure that neither player unduly delays the game. Clocks may be analog or digital. Digital clocks work best in backgammon because they have a time delay feature. Chouette [Pronounced "shoo-ETT". From the French word for "barn owl," a bird that is often attacked by all other birds.]  A social form of backgammon for three or more players. One player, the box, plays on a single board against all the others who form a team led by a captain.  See: How to Run a Chouette. Cinque-Point Traditional name for the five-point. Claim a Game To offer a double which you believe will be refused so that you can collect the current value of the cube; cash a game. Clean Play A move completed legally. Clear a Point To move all the checkers off of a point (1). Clear from the Rear A good general strategy to use when bearing in or bearing off against opposition. You clear your highest point (1) first and avoid creating gaps. Client Software Software that runs on a user's computer and communicates with a backgammon server to allow the user to play backgammon (1) with others on the Internet. The client software displays the board and interacts with the user as he rolls the dice and moves the checkers. Clock Chess clock. Clockwise The direction your checkers move around the board when they are set up to bear off to the left. When your checkers move clockwise, your opponent's checkers move counterclockwise. Close a Point Make a point; place two or more of your checkers on a point (1), and thereby prevent your opponent from landing there. Closed Board A player's home board when all six points (1) are blocked. Closed Point A point (1) containing two or more checkers; a block or an anchor. Close Out To make all six of your home board points while the opponent has one or more checkers on the bar. The opponent is then prevented from entering his checker or making any other move until one of the closed home-board points is opened. Cluster Count A collection pip counting techniques used by Jack Kissane and described in this article. Cocked Dice Thrown dice which do not both land flat on the surface of the half of the board to the player's right. The roll is disqualified and both dice must be rethrown. Cock Shot Entering from the bar with a roll of 6-2 and hitting a blot on the eight-point when the only open point is the two-point. Coffeehouse Misleading talk to confuse opponent. For example, in a chouette, when a team player advises the captain not to double knowing full well that the captain will double, he tempts the box to unwisely accept (ethically borderline, at best). (From Backgammon, by Paul Magriel, p 396.) Combination The two numbers on a pair of rolled dice taken together; see combinations of the dice. The play of a single checker that uses both numbers of a roll, such as a combination shot. Combination Shot An opportunity to hit an opposing blot that requires using the numbers on both dice taken together; an indirect shot.   Compare: Direct Shot. Combinations of the Dice The number of possible rolls out of 36 that accomplish a specific objective. Comeback Shot An opportunity to hit an opponent's blot immediately after being hit yourself; in particular, an opportunity to hit from the bar. Come In Enter. Comfort Station Mid-point. Committed Position A position from which there is only one reasonable game plan for winning, as opposed to a noncommitted position. Communicate To keep checkers within six pips (2) of one another for mutual support; see connectivity. Compact Position A position with several made points close to one another and few gaps. Compact positions are powerful because spare checkers can easily build new points and rear points can be broken safely. Confetti What you sometimes get paid in if you are not careful with whom you play. Confidence Interval A range of values that contain, with a certain probability, a rollout's convergence value. For example, with a 95%-confidence interval, there is only a 5% chance that performing the same rollout an infinite number of times will yield a result outside the interval. See post by Stig Eide. Connected Position A position in which all fifteen of a player's checkers are located within a short distance of each other. A position which is well-connected will tend to stay well-connected. Connectivity The degree to which all of a player's checkers work together as a unified army without large gaps between them. Connected checkers defend each other and are easily made into points (2). Consolation Division Consolation flight. Consolation Flight A event for players eliminated early in the main flight of an elimination tournament; sometimes called a sympathy flight. Consolidate To reduce the number of blots a player has, frequently as a precursor to offering a double. Consultation Advice offered by the crew to the captain in a chouette. Contact Position A game where the opposing forces have not moved past each other and where it is still possible for one player to hit or block the other.   Compare: Pure Race. Contain a Checker To prevent an opposing checker from escaping to its own side of the board by blocking it or hitting it and sending it back. Control a Point A player controls a point (1) if he has two or more checkers on that point. Only the player who controls a point may move additional checkers to that point. Control the Cube Own the cube. Convergence Value (of a Rollout) The value approached by a rollout as more and more trials are performed. It is the result you would obtain if you could do a rollout an infinite number of times. Correspondence Games Games played by e-mail. Count Pip count. The relative standing of the players' pip counts. The player with the lower pip count is said to be ahead in the count. Counter Checker. Counterclockwise The direction your checkers move around the board when they are set up to bear off to the right. When your checkers move counterclockwise, your opponent's checkers move clockwise. Counterplay Possibilities for retaliation, switching from a defensive posture to an offensive posture. Count the Position To tabulate the players' pip counts to find out who is ahead in the race and by how much. Coup Classique A win from the seemingly unwinnable position in which your opponent has borne off twelve checkers and has just three checkers remaining on his two-point. You bravely maintain contact with a single checker on his one-point and deploy your other fourteen checkers where they can contain his checkers if you are able to hit one or, preferably, two of them. Winning a coup classique is especially satisfying for you and maddening for your opponent. Cover a Blot To add a second checker to a blot, thereby making the point. CPW Cubeless probability of winning. Cramped Having little or no mobility. Crawford Game The first game in a match after either player comes to within one point (4) of winning. The rules of match play say that the doubling cube may not be used during the Crawford game.  See: Crawford Rule. Crawford Rule [Named for John R. Crawford.]  A standard rule of match play. When the leading player comes within one point (4) of winning the match, the following game is played without a doubling cube. This one game without doubling is called the Crawford Game. After the Crawford game, the doubling cube is back in play again. See posts by: Chuck Bower, Kit Woolsey, and Walter Trice. Crew In a chouette, members of the team who play with the captain against the box. Crossover The movement of a checker from one quadrant of the board to an adjacent quadrant. Crossover Count The total number of crossovers needed to get all your checkers home and then borne off. Crunch The forced evacuation of desirable points (2) due to the lack of alternate plays; in particular, a position in which you are forced to bury checkers deep within your home board. Crunched Position A position which has collapsed, with several checkers being forced to the low points (1) in the player's home board while other checkers remain in the opponent's territory. Crunching Position A priming game in which one side is about to collapse, but has not done so yet. Cube [Noun.]  Doubling cube. [Verb.]  To offer a double. Cube Action All of the cube decisions associated with a given position, namely: (a) whether the player on roll should double, and (b) whether his opponent should accept the double, refuse the double, or possibly beaver. Cube Decision The choice of whether or not to offer a double, or the choice of whether to accept, or refuse a double that has been offered. Cubeful Equity In money play with the doubling cube, the absolute value of a position to one of the players compared to the initial stake being played for.  See: Equity. Cubeful equity considers the current value of the cube, cube ownership, and the potential for future doubles. In match play, cubeful equity corresponds to the probability of winning the match from the current position.  Compare: Cubeless Equity. Cubeful Rollout A rollout performed with the doubling cube in play. All appropriate cube decisions are made as the position is played out. That means some trials will end in a dropped double and others will end with the cube at 2, or 4, or even higher. Cubeful rollouts more accurately simulate actual games than cubeless rollouts, but they have greater variance, so they do not converge as quickly. And cubeful rollouts may be more susceptible to systematic error because of cube misplays. Cube Handling The art or skill of making cube decisions. Cube in the Middle See: Centered Cube. Cubeless Equity The value of a position if the game is played without a doubling cube. This is a value between -3 and +3 and is equal to P(W) + P(Wg) + P(Wbg) - P(L) - P(Lg) - P(Lbg), where P(W) is the probability of winning the game, P(Wg) is the probability of winning a gammon (or backgammon), P(Wbg) is the probability of winning a backgammon, P(L) is the probability of losing the game, P(Lg) is the probability of losing a gammon (or backgammon), P(Lbg) is the probability of losing a backgammon.  Compare: Cubeful Equity. Cubeless Probability of Winning The chance of winning the game if no doubling cube is used; also called game winning chances. Cubeless Rollout A rollout performed without using a doubling cube. Each trial is played to the end of the game and scored plus or minus 1, 2, or 3 points (4) depending on whether gamed ended in a single game, gammon, or backgammon (2). Because cubeless rollouts do not include cube play, they do not perfectly simulate a game, but cubeless rollouts have less variance and less systematic error than cubeful rollouts. Cube Ownership Which player has the right to make the next double. At the start of the game, the cube is in the middle and either player may double. After one player accepts another's double, he owns the cube, and only that player may make the next double. Cube Play The act of offering a double, or the act of accepting or refusing the opponent's double. The art or skill of making cube decisions.  Compare: Checker Play (2). Cube Proxy A player in a chouette who temporarily handles the cube for another while that player is away from the game. See post by Ilia Guzei. Cube Reference Position A position for which the correct cube action is known which serves as a standard by which other similar positions may be judged. See post by Chuck Bower. Cup Dice cup. Current Stake The initial stake multiplied by the value of the doubling cube.

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Dance [From the action a player makes as he reaches to enter his checker, then pulls his arm back when he notices the numbers are blocked.]  To throw numbers which fail to enter a checker from the bar. Dead Checker A spare checker deep in the player's home board where it serves no useful purpose.  See: Bury a Checker. Dead Cube A doubling cube with no further doubling value. In match play, the cube is said to be dead when the player owning the cube has no reason to double. For example, a player who owns a 2-cube when he is two points (4) away from winning the match will never double because he can win the match with the cube at its current level. Dead Man Dead checker. Dead Number A specific number on the dice which cannot be played in the current position; see kill a number. Decline a Double Refuse a double. Deep On a low-numbered point (1), usually the one-point or two-point. Deep Anchor An anchor on the opponent's one-point or two-point. Deuce A rolled die showing the number 2. Deuce-Point Traditional name for the two-point. Dice [Plural of die.]  Two small cubes, each with faces marked with spots (pips (1)) representing the numbers 1 to 6. Dice for backgammon usually have rounded corners so they roll more easily. You throw a pair of dice at the start of each turn, and move your checkers according to the numbers thrown. Dice Combination One of the 36 possible rolls using two dice. Dice Cup A container, often of leather or plastic, used for shaking and rolling dice. Dice cups often have a ridge around the inside of the open end designed to "trip up" the dice as they leave the cup. Dice cups make dice manipulation harder and help ensure randomness of the rolls. Dice Manipulation Any unfair means used to influence the roll of the dice. See post by Kit Woolsey. Dice Mechanic A person skillful in the use of unfair means to control the dice. Die Singular of dice. Digital Clock An electronic chess clock with digital displays showing the time remaining for each player. A display shows 00:00 when a player has run out of time. Digital clocks typically have a time delay feature which makes them particularly well suited for backgammon.  Compare: Analog Clock. Dilly Builder A spare checker which bears only on points deep in a player's home board. Direct Hit A hit using the number on just one die. You must be within six points of a blot to be able to hit it directly.   Compare: Indirect Hit. Direct Range Reachable using a single number from one die. For example, a blot is in direct range of being hit if it is six points or less away from an opposing checker. Direct Shot A chance to hit a blot six points or less away using a single number from one die. Disengage To break all contact and turn the game into a pure race. Disjointed Position A position that is poorly connected, in which a player's army is divided into two or more groups with large gaps between them. Distribution The arrangement of checkers among points. A good distribution is compact with spares on most points. You don't want too many points or too few points (candlesticks). Diversification The spreading out of your checkers to increase the number of good rolls on your next turn. See post by Simon Woodhead.  Compare: Duplication. Division One of the sections in a tournament into which players are divided according to their ability and experience. For example, a tournament might have a novice division, an intermediate division, and an open division. DMP Double match point. Double An offer made by one player to his opponent during the course of a game (just before the player rolls the dice) to continue the game at twice the current stakes. The opponent may refuse the double, in which case he resigns the game and loses the current (undoubled) stakes. Otherwise, he must accept the double and the game continues at double the previous stakes. A player who accepts a double becomes owner of the cube and only he may make the next double in the same game. Double Bump Double hit. Double Direct Shot Double shot. Double Ducks The roll of 2-2 on the dice (double 2's). Double Elimination A tournament format in which a competitor continues playing until he has lost twice.  Compare: Single Elimination. Double Game Gammon. Double Hit To hit two opposing blots on one turn. Double Jeopardy Potential for awkward rolls both next turn and the turn after. Double Match Point A match in which both players need just one more point (4) to win. A game in which the doubling cube has reached a high enough level that a win by either player also wins the match. Double Oneself Out To offer a double which, if accepted, will win the match for that player if he goes on to win the game. Doubler Doubling cube. Doubles Two thrown dice with identical numbers on their upper faces. Double Shot One blot which can be directly hit two different ways, or two blots each of which can be directly hit one way.  Compare: Single Shot. Doublets Doubles. Doubling Block Doubling cube. Doubling Cube A cubical block, slightly larger than a regular die, with the numbers 2, 4, 8, 16, 32, and 64 marked on its faces. It is used for keeping track of the increase in stakes of the game and the player who next has the right to double. The cube starts in the middle with the number 64 facing up (representing a value of 1). When you offer a double, you turn the cube to its next higher value and pass it to your opponent. If he accepts your double, he places the cube on his side of the board and becomes the owner of the cube. After the first double of a game, only the player who last accepted a double may make the next double. Rules that affect use of the doubling cube:  automatic doubles, the Jacoby rule, and beavers. Doubling on the Come Offering a double in anticipation of a good roll. Doubling Window The range of game winning chances which are both a proper double and a proper take. The range of game winning chances which would be a proper double and a proper take if neither player could use the cube again. Down An early-game move of a checker from the mid-point to the same player's outer board. Draw The random pairing of competitors in a tournament to determine who will play whom or who will get byes. Drop Refuse a double. Dropper [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. Drop Point 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. Drop-Take 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. Ducks Double ducks. Duplicate Backgammon 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. Duplicate Dice 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. Duplicate Tournament See: Duplicate Backgammon. Duplication 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. Dutch Backgammon A backgammon variant in which the players start with all their checkers off the board.  See: How to Play Dutch Backgammon. Dyscommunication [Coined by Danny Kleinman in Double Sixes from the Bar.]  The negative impact on flexibility of having spare checkers exactly six pips apart.

E

Early Game The first few moves of a game, before the players have settled on a particular game plan. Early-Late Ratio 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. See post by Tom Keith. Edge of a Prime The open point directly in front of a prime. Effective Pip Count 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. Efficient Double A double made at its point of maximum effectiveness, when the opponent would be correct to either accept or refuse. Eject To abandon an ace-point game to avoid losing a backgammon (2) or a gammon. Elimination Format A tournament event in which half the competitors are eliminated each round until just one player remains.  Compare: Round Robin Format. Elo Ratings System 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. EMG Equity Equivalent-to-money-game equity. End Game The phase of a game which starts when either player begins to bear off. Enter To move a checker from the bar to an open point in the opponent's home board according to a roll of the dice. When a player has a checker on the bar, this is his only legal move. EPC Effective pip count. Equity The value of a position to one of the players. Equity is the sum of the values of the possible outcomes from a given position with each value multiplied by its probability of occurrence. It is the same as the fair settlement value of the position. Your equity is the negative of your opponent's equity. See post by Gary Wong. Equity comes in different flavors.  See: Cubeless Equity, Cubeful Equity, Match Equity, and EMG Equity. Equivalent-to-Money-Game Equity Cubeful equity normalized by transforming it linearly so that winning a single game at the current value of the cube is reported as +1 and losing a single game at the current value of the cube is reported as −1. EMG equity is commonly used in match play to compare the size of errors in different games. See the Snowie Support FAQ for a further description and an example. Error Rate A measure of the average equity lost per move due to errors in play. The lost equity can be measured either in match-winning chances or EMG equity. Different programs compute error rate differently: Snowie divides by the total number of moves and reports the rate in "millipoints per move." Gnu Backgammon divides by the number of unforced plays. See post by Gregg Cattanach. Escape To advance a runner to safety or past the opponent's blockade. Establish a Point Make a point. Eureka [Also spelled "Eureika".]  Simplified backgammon, in which each player starts with two checkers on his one, two, and three-point, and three checkers on his four, five, and six-point. See How to Play Eureika. Exposed Checker A blot within range of a direct hit. Extras See: Mandatory Extras.

F

Fan To fail to reenter after being hit; to dance. Fast Board Speed board. Favorite The player judged most likely to win a game or match.  Compare: Underdog. Fevga [Also spelled "feuga".]  A Greek game similar to Moultezim in which players start at diagonally opposite corners of the board and move in the same direction. There is no hitting and one checker by itself controls a point.  See: How to Play Fevga. FIBS First Internet Backgammon Server, an electronic forum for playing backgammon with others from around the world.  Website: FIBS. FIBS Rating A number associated with each player based on that player's record of performance against other rated players. Every player starts with a rating of 1500. Your rating goes up when you win and down when you lose. The size of the change depends on whether the favorite wins (less change) or underdog wins (greater change).  See: FIBS Rating Formula. FIBS Rating Formula The ratings system used on FIBS. Most other backgammon servers use similar systems. See this article by Kevin Bastian for a description of the formula. Field Goal When you have an opportunity to hit two checkers that are two spaces apart and roll a number than lands between them. Finalist One of the two players competing in the finals of an elimination tournament. Finals The last match that determines the overall winner of an elimination tournament. Fischer Clock A chess clock with a feature that adds a given amount to a player's time after each move. A Fischer clock is better for backgammon than using a standard analog clock, but not as good as a digital clock with a time delay feature. Fish Derogatory term for a poor player willing to play for high stakes. Five-Point The fifth point (1) in a player's home board, counting from the edge of the board toward the bar. A very strong point to acquire early in a game. Flexibility The degree to which checkers are arranged to allow the greatest number of future rolls to play constructively or at least comfortably. Flight A chart showing which players play each other in an elimination tournament. Flunk To fail to enter a checker from the bar; to dance. Fly Shot A long indirect shot with few combinations (2); in particular, a roll that hits an outfield blot from the opponent's one-point. Fold Refuse a double; pass. Forced Play A roll of the dice for which there is only one legal play. Forward Anchor Advanced anchor. Forward Game A game plan in which the chief objective is to enter as rapidly as possible into a pure race; a running game. Any game plan other than a back game. Four-Point The fourth point (1) in a player's home board, counting from the edge of the board toward the bar. Free Drop In match play, after the Crawford game has been played and the trailing player has an even number of points to go, the option of the leading player to refuse a double without reducing the number of games his opponent will need to win. See this thread.  See also: Mandatory Double. Freeze a Builder To bring a checker to bear on a point (1) held by exactly two opposing checkers, and thus restrict the use of those checkers as builders. Freeze-Out Match An alternative to match play in which two players each begin with a predetermined amount of money or points (4) and play using table-stakes betting until one of them loses everything he started with. See post by Dave Brotherton. French Backgammon A backgammon variant in which players start with all their checkers off the board and doubles are played using both sides of the dice.  See: How to Play French Backgammon. Front a Prime To make a point directly in front of an opponent's prime. Frozen Cube Dead Cube. Full Prime A prime of six consecutive points (2) which completely block the opponent from escaping.  Compare: Partial Prime.

G

Gain a Tempo Hit the opponent and thereby deprive him of half a roll. Game Plan A strategy for winning the game. The three major game plans are run, block, and attack. Gamesmanship The use of ethically dubious means to obtain an advantage in a game. This includes intentionally distracting, confusing, or generally duping an opponent. See post by Albert Steg. Game Winning Chances The probability of winning the current game if it is played to conclusion without a doubling cube; also called cubeless probability of winning. Gammon A completed game of backgammon in which the losing player has not borne off any checkers. A gammon is also called a double game because the winner receives twice the value of the doubling cube.   Compare: Single Game and Backgammon (2). In money play, with the Jacoby rule in effect, gammons do not count if the doubling cube has not been turned that game. Gammon Count The minimum number of pips a player needs to roll to bring all his checkers home and bear off his first checker, thereby avoiding losing a gammon.  Compare: Pip Count. Gammon Cube Jacoby rule. Gammon-Go A situation in match play where losing a gammon has no cost, but winning a gammon is particularly valuable. Examples: (a) you trail 4-away/2-away and opponent owns the cube at 2; or (b) you trail 2-away/1-away in the Crawford game; or (c) you trail 3-away/1-away after the Crawford game and the cube is at 2. Gammon-go for you is gammon-save for your opponent. See posts by Mary Hickey and Marty Storer. Gammonish A position that has a higher than normal gammon rate. Gammon Price The relative value of winning a gammon compared with the value of winning a single game. Gammon price is computed as GP = (WG - W) / (W - L), where WG = value of winning a gammon, W = value of winning a single game, and L = value of losing a single game. In money play, the gammon price is 50%. In match play, the gammon price depends on the score of the match and the level of the doubling cube. See posts by David Montgomery and Ron Karr. Gammon Rate The chance of a game ending in a gammon or a backgammon (2) if played to completion (i.e., without a doubling cube). Gammon rate may refer to a particular game in progress or to backgammon games in general. An individual player's gammon rate is the fraction of his wins which are gammons or backgammons. See post by David Montgomery. Gammon-Save A situation in match play where winning a gammon has no value, but losing a gammon is particularly costly. Examples: (a) you lead 2-away/4-away and own the cube at 2; or (b) you lead 1-away/2-away in the Crawford game; or (c) you lead 1-away/3-away after the Crawford game and the cube is at 2. Gammon-save for you is gammon-go for your opponent. See posts by Mary Hickey and Marty Storer. Gammon Vigorish (Vig) The additional equity resulting from the possibility of winning a gammon. Gap The space or spaces between made points. GG Gammon-go. Gin Position A position from which a player cannot lose. Gioul A Middle Eastern game in which a single checker controls a point (1) and doubles are very powerful.  See: How to Play Gioul. Girls (The Girls) A roll of 5-5 (double 5's). Give a Little Present to Double. Giving for Game A statement made by a player in a chouette that he is willing to pay the captain or any other team member the full stake at which the game currently stands for the right to take over their games. The player making this offer does so because he wishes to double the box when the other players to do not. GNU Backgammon A neural-net computer program that plays backgammon (1) and analyzes positions and matches. GNU Backgammon is a cooperative effort of many volunteers. It is "free" software as defined by the GNU General Public License. See the post by Gary Wong and the tutorial by Albert Silver.  Website: GNU Backgammon. Golden Point [Coined by Paul Magriel in his book Backgammon.]  The opponent's five-point, the best place to build an anchor. Go Out To achieve the points (4) necessary to win a match. Greedy Bearoff A mode in some computer programs and on some backgammon servers where the computer will automatically bear off the maximum number of checkers possible. Greek Backgammon Tavli. GS Gammon-save. Guff (Guffy) A player's one-point. Gul Bara A Middle Eastern game in which a single checker controls a point (1) and doubles are very powerful.  See: How to Play Gul Bara. GWC Game winning chances.

H

Half a Roll One of the two numbers on a pair of thrown dice. Half-Crossover Method A pip counting method devised by Douglas Zare. See this post and this article. Handicap An artificial advantage given to a weaker player in an effort to equalize the chances of winning. Some popular handicaps are: (a) the weaker player gets to go first; (b) once during the game the weaker player gets to reroll if he doesn't like his roll; (c) the weaker player gets to start the game owning the cube; (d) the weaker player gets to start the game with a strong roll such as 5-3, 4-2, 6-5, or 3-1. Hara-Kiri Play A play which exposes blots for the purpose of recirculating the player's checkers; also known as a suicide play. Head-to-Head One player against another player for money. Heavy Point A point (1) with more than three checkers on it. Hedge A side bet between two players prior to competing in the final rounds of a tournament designed to protect the loser from going away empty handed. For example, two players competing for a $10,000 prize might agree beforehand that the winner will pay the loser $2,500. See this thread. Hit To move to a point (1) occupied by an opposing blot and put the blot on the bar. Hit and Cover To hit an opposing blot and then continue on with the same checker to cover your own blot. Hit and Pass Pick and pass. Hit and Run Pick and pass. Hit and Split To hit a blot with one number while splitting your runners with the other number. The hit provides protection for the advanced split checker, making it less likely the opponent will be able to point on it. Hit Loose To hit an opposing blot and while leaving your own blot(s) in danger of a return hit, particularly in your own home board. Hit Off the Edge of a Prime To hit an opposing blot sitting on the front edge of a partial prime to keep the blot from escaping. Holding Game A strategy used when you are behind in the race and your opponent has escaped his runners. You make an advanced anchor on the opponent's side of the board and hold on to it as long as you can with the idea of hindering the opponent from bearing in safely. See this thread.  Compare: Back Game. Holding Point The defensive point (2) you control when playing a holding game, usually the opponent's four-point, five-point, or bar-point. Holland Rule [Named after Tim Holland, who proposed the rule.]  An optional rule in match play that was popular in the 1980's but is now rarely used. After the Crawford game a player may not double until at least two rolls have been played by each side. See post by Kit Woolsey. Home Home board. Home Board