From: Backgammon Galore Backgammon Glossary By Tom Keith ©1996-1997 A list of terms and jargon specific to the game of backgammon, with definitions. If you have suggestions or corrections for this glossary, please send email to tom@bkgm.com. Thumb index: A B C D E F G H I J K L M N O P Q R S T U V W X Y Z + Credits A 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 Point A player's one point. Ace Point Game A position in the late stages of a game in which a player is trapped on the opponent's ace point trying to hit a shot as the opponent brings his checkers home and bears them off. Acey-Deucey The roll of 2 and 1 with two dice. A variation of backgammon in which the roll of 2 and 1 gives the player extra turns. Action Play A play designed to provoke an exchange of hits, typically used after the opponent has escaped his runners. Active Builder A checker which is completely free to make another point. Anchor A point occupied by two or more of a player's checkers on the opponent's side of the board. An advanced anchor is an anchor on the opponent's four or five point or any anchor outside the opponent's home board. Around the Corner A move from the opponent's outer board to the player's outer board. Attacking Game Blitz. Automatic Doubles An optional rule in money play which states: if both players roll the same number on the first roll of a game, the stakes are to be doubled. Players usually agree to limit the number of automatic doubles to one per game. Awkward Number A dice roll which causes the player's position to deteriorate. B Back Game A strategy employed by a player who is substantially behind in the race but holds two or more points in the opponent's home board. The player deploys his other checkers where they will be effective blocks, and hopes to hit blots left by the opponent as the opponent brings his checkers home and bears them off. The success of this strategy depends on timing. Compare: running game. Backgammon A board game played with dice and checkers in which each player tries to move his checkers home and bear them off while preventing the opponent from doing the same thing. A completed game of backgammon 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. (Also called a triple game because the winner receives three times the current stake.) Compare: single game and gammon. Backgammon Server A computer used to arrange and mediate games of backgammon between players on a computer network. The server rolls the dice, maintains the board, communicates the plays to each player, and keeps score. Bar The raised ridge down the center of a backgammon board dividing the home board from the outer board, where checkers are placed after they have been hit. A player with a checker on the bar must enter that checker before he can make any other move. Bar Point A player's seven point, so named because it is physically adjacent to the bar. Bear In To move a checker into the player's home board in preparation for bearing off. Bear Off To remove a checker from the board according to a roll of the dice, after all of the player's checkers have been brought into his home board. Beavers An optional rule in money play which says that when a player is doubled, he may immediately redouble (beaver) while retaining possession of the doubling cube. The original doubler has the option of accepting or refusing as with a normal double. Black One of the participants in a backgammon game, presumably the one using darker-colored checkers. Also, the checkers used by this player. Blitz The strategy of an all-out attack on blots in the player's home board aimed at eventually closing out the opponent. Block A point occupied by two or more of a player's checkers on the player's side of the board. Blockade A contiguous or nearly contiguous series of blocks arranged to prevent escape of the opponent's runners. Blot A checker residing alone on a point, where it is potentially exposed to being hit. Blot Hitting Contest An exchange of loose hits in which both players try to gain a key point. Board The entire playing area of a backgammon game. One quadrant of the playing area, such as a player's home board or a player's outer board. A player's home board when it is closed out, as in to make one's board. Box In a chouette, the player who plays alone against all the others. He is said to be in the box. Break Contact To move the last of a player's checkers past the last of the opponent's checkers and proceed to the final stage of the game in which there is no hitting or blocking. Break a Point To remove one of your checkers from a position on the board that contains only two checkers, and thus leave that point open. (This is the opposite of making a point.) Builder A checker brought into the player's outer board, often from the mid point, for the purpose of using it later to make another point. C 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 also: description by Toni Wuersch. Candlesticks A position in which a player's checkers are piled high on just a few points. Captain In a chouette, the leader of the team playing against the box. He has the final say on the play of the team. Cash To offer a double when a player knows it will be refused and thereby convert the player's advantage in the game into money or points. Centered Cube The state of the doubling cube before either player has offered a double. Checker One of the fifteen white or fifteen black markers that the players move around the board according to rolls of the dice. (Also called a man, piece, or stone.) Chouette (Pronounced "shoo-ETT.") A social variant of backgammon for more than two players. One player, the box, plays on a single board against the others who form a team lead by a captain. Close Out To set up blocks on all six points in a player's home board while the opponent has a checker on the bar. The opponent is thereby prevented from entering his checker and can make no further plays until at least one of the blocked points is opened. Closed Board A player's home board when all six points are blocked. Closed Point A point containing two or more of the opponent's checkers. Cocked Dice Illegally thrown dice. Any time a die lands on a checker, off the board, or in any manner other than flush and flat on the half of the board to the player's right, the roll is disqualified and both dice must be rethrown. Combination The two numbers on a pair of rolled dice taken together. The play of a single checker that uses both numbers of a roll. Comeback Shot A roll which enables a checker on the bar to hit a blot. Communicate To keep checkers within six pips of one another for mutual support. Consolidate To reduce the number of blots a player has, frequently as a precursor to offering a double. Contact A position in which it is still possible for one player to hit or block the other, as compared to a race. 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. Cover a Blot To add a second checker to one of the player's blots and thereby make a point. CPW Cubeless Probability of Winning -- a player's chances of winning the game if no doubling cube is being used. Crawford Rule An optional rule for match play which states: if the leading player attains a match score one game short of victory, the next game of the match is to be played without a doubling cube. This one game in which neither player may double is called the Crawford game. (Named for John R. Crawford.) Cross Over The move of a checker from one quadrant of the board to an adjacent quadrant. One of the future moves from one quadrant to the next that a checker must make to reach its home board. Crunch The forced evacuation of desirable points because of the lack of alternate plays. Cube Doubling cube. Cube Decision The choice of whether or not to offer a double, or the choice of whether to accept, or refuse when a double has been offered. Cube Ownership Indicates which player next has the right to double. If, during the course of a game, one player accepts a double offered by the other, that player is now said to own the cube, and only he may offer the next double. The current state of the doubling option from the point of view of one of the players. There are three possibilities: Positive cube ownership, when only that player may double. Neutral cube ownership, when both players may double. Negative cube ownership, when only the opponent may double. D Dance To toss an unplayable roll; in particular, to fail to reenter after having been hit. Dead Checker An extra checker deep in the player's home board. Dead Cube The doubling cube in match play when it offers no utility to a player who has the option of doubling. An example is when the cube equals or exceeds the number of points the trailing player needs to win the match. Dead Number A specific die value which cannot be played in the a position. Decline a Double Refuse a double. Deep On a low-numbered point, usually the one or two point. Dice Cup A cylindrical container, closed at one end, with a ridge around the inside of the open end, used for shaking and rolling dice. Dilly Builder A spare checker which bears only upon points deep in a player's home board. Disengage Break contact. Diversification The spreading out of a player's checkers to increase the number of good rolls on a subsequent turn. See also: duplication. DMP Double match point. Dominate To be at least as good as in all respects. One play is said to dominate another (similar) play if it is as good as the other play by any measure of comparison. Spotting dominated plays can reduce the total number of plays to choose among in a given position. Double An offer made by one player to his opponent during the course of a game (just before the player rolls the dice to start his turn) to continue play 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, the opponent must accept the double, in which case the game continues at twice the stakes with the opponent acquiring ownership of the doubling cube. After the first double of a game, only the player that most recently accepted a double (the player who owns the cube) may redouble. Double Game See Gammon. 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 to win. A game in which the doubling cube has reached a level high enough that if either player wins the game they also win the match. Double Oneself Out To offer a double which, if accepted, will win the match for the doubler if he wins the game. Doubles Two thrown dice with the same number on their upper face. Compare: mixed roll. Doubling Cube A cubical block with the numbers 2, 4, 8, 16, 32, and 64 marked on its faces, used for keeping track of the increase in stakes of a game and the player who has the right to make the next double. Doubling Window From "Cubes and Gammons near the End of the Match" by Antonio Ortega and Danny Kleinman: "The range of winning percentages that may justify giving your opponent a cube that he should certainly take. The top of your doubling window is your cashpoint--the complement of your opponent's takepoint. The bottom of your doubling window is the minimum game-winning chance at which you are better off doubling your opponent in, than ending the game with the cube at 1. Clearly, you should double at your very last turn of the game if you have reached the bottom of your doubling window." Drop Refuse a double. Dropper A player on a backgammon server who avoids a loss by intentionally leaving a match before it is finished. Drop Point The maximum equity at which it is the correct for a player to refuse a double. (Also, the minimum equity at which it is correct for a player to accept a double.) For cubeless equity, the drop point ranges between -0.667 and -0.500, depending on the recube vigorish. For cube equity, the drop point is -1. Drop-Take In a chouette, an agreement between two players after a double by the box that one of them will accept the double, the other will refuse, and they will pool the net result. Duplication A position in which two or more of the opponent's good moves both use the same number. For example, when the opponent needs the same number to hit either of two blots, that number is 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. E Edge of a Prime The open point directly in front of a prime. Efficient Double A double made at the point of maximum effectiveness, when the recipient would be correct to either accept or refuse. End Game The phase of a game which starts when either player begins to bear off. The phase of a game in which no further contact is possible. Enter To move a checker from the bar to a 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. Eject To abandon an ace-point game so as to avoid losing a backgammon or gammon. Equity The expected value of a backgammon position. Specifically, the sum of the values of the possible outcomes from a given position with each value multiplied by its probability of occurrence. Three types of equity are commonly quoted: Cubeless Equity. The value of a position compared to the value of winning a single game, without regard to the effect of the doubling cube. This is a value between -3 and +3 and is equal to P(player wins) - P(player loses) + P(player wins gammon) - P(player loses gammon) + P(player wins backgammon) - P(player loses backgammon) Cube Equity. In money play with a doubling cube, the value of a position to one of the players compared to the current stake being played for. Cube equity considers cube ownership as it relates to the potential for future doubles, but does not consider the current value of cube. Settlement Equity. The value of a position in a money game to one of the players and the fair value, as a factor of the initial stake, that should change hands in lieu of finishing the game. Settlement equity is equal to cube equity times the current value of the doubling cube. See also: descriptions by Michael Zehr and Chuck Bower. See also: match equity. Expert Backgammon A computer program that plays backgammon and performs rollouts, written by Tom Weaver. Exposed Checker A blot within range of a direct shot. Extras An optional rule for chouettes used when only some of the players on the team accept a double from the box. Any of the team members who refused the box's double may give an extra cube to a player who accepted the double. This is essentially a side bet on the game in progress. Extra cubes are offered at the same level as the original cube and must be accompanied by a payment equal to one half their value. When the game is over, the receiver of an extra will collect or pay off on the extra cube in the usual manner. Some chouettes make it mandatory that extra cubes be accepted; others make it optional. See also: explanations by Toni Wuersch, Albert Steg, and Daniel Murphy. Mandatory extras. An optional rule for money play which says that whenever a double is offered and accepted, the doubler has the right to give his opponent an extra cube at the same level. The extra cube must be accompanied by a payment equal to one half of its value. The receiver then has two cubes which he may use together or separately for making future doubles. F Fan To toss an unplayable roll; in particular, to fail to reenter after having been hit. FIBS The First Internet Backgammon Server, an electronic forum for playing backgammon with others from around the world, developed by Andreas Schneider. 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. Fish A poor backgammon money manager. Fly Shot A long indirect shot with few combinations. Forced Play A roll of the dice for which there is only one legal play. Forward Game Running game. 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 the trailing player needs to win the match. See also: mandatory double. Free Drop Vigorish In match play, after the Crawford game, the slight advantage the leader has when the trailer is two points away from victory because the leader has the option of refusing when the trailer offers a double. See also: mandatory double, free drop. Freeze a Builder To bring a checker to bear upon a point held by only two of the opponent's checkers and thus restrict these checkers from being active builders. G Gammon A completed game of backgammon in which the losing player has not borne off any checkers. (Also called a double game when it is not a backgammon because the winner receives twice the value of a single game.) Gammon Price The relative value of winning a gammon versus winning just a single game. Gammon price is computed as GP = (WG - W) / (W - L), where WG is the value of winning a gammon, W is the value of winning a single game, and L is the 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; it can range anywhere from 0 (e.g., at double match point) to well over 100%. See also: explanations by Ron Karr and David Montgomery. Gammon Rate The fraction of games which end in a gammon or a backgammon. This includes games which would end in a gammon if they were played to completion but are not because a player doubles and the opponent refuses. Gammon Vig, or Gammon Vigorish The additional equity resulting from the possibility of a gammon. Gap The space or spaces between established points. Golden Point A player's twenty point (the opponent's five point). Go Out To achieve the points necessary to win a match. GWC Game winning chances. Guff, or Guffy A player's one point. H Half a Roll One number showing on a pair of tossed dice. Hara-Kiri Play A play which exposes blots for the purpose of recirculating the player's checkers. Heavy Point A point with more than three checkers on it. Hit To land on a point where there is an adverse blot, and put the blot on the bar. Hit and Cover To hit an adverse blot and then cover the player's own blot, in a single play with a single checker. Hit Loose To hit an opposing checker at a time when the player's own blots are in danger of a return hit. Holding Game A game in which one player occupies a point or points on the opponent's side of the board to make it more difficult for the opponent to bring home his checkers safely. Holland Rule An optional rule for match_play to be used in conjunction with the Crawford rule. It states that after the Crawford game neither player may double until two rolls have been played by each side. (Named for Tim Holland.) Home Board The side of the board where the players bear off their checkers. Each player's home board comprises that player's points one through six. See also: outer board. I Inactive Builder A checker which may be available in the future to make another point but which is presently occupied otherwise (such as helping to form a block). Inner Table Home board. J Jacoby Rule An common rule for money play which says that gammons and backgammons are to count only as a single game if neither player has offered a double during the game. (Named for Oswald Jacoby.) Janowski's Formula A formula devised by Rick Janowski for estimating match equity at a given match score. It says that if d is the difference in match score and t is the number of points the trailing player has to go, then the probability of the leading player winning the match is .5 + .85d / (t+6) . See also: Neil's Numbers. Jellyfish A computer program that plays backgammon and performs rollouts, developed by JellyFish AS. Jeopardy Potential for awkward rolls on a future turn. Joker An exceptionally good roll, especially a roll that reverses the likely outcome of the game. An example of a joker would be a roll of double sixes to bear off your last four checkers when your opponent otherwise wins on his next turn. K Kauder Paradox The fact that in money play with the Jacoby Rule in effect, a position can theoretically be both a proper double and a proper beaver. By doubling, the underdog gets full value for his potential gammons, thus raising his equity. However, as long as this equity remains negative, the doubler's opponent should naturally beaver. Kibitzer A spectator who often offers unwanted advice or comment. Kill a Checker To move an extra checker deep within a player's home board where it serves no useful purpose. Kill a Number To create a position in which a specific die value cannot be played on the next turn. L Last Roll Position The last position of a game in which both players still have a chance to win. Lover's Leap With an opening roll of 6 and 5, the play of a checker from the twenty-four point to the thirteen point. M Make a Point To place two checkers together at one position so they form a block or an anchor. Mandatory Double A situation possible in match play in which it is correct for a player to double based solely on the match score. In any post-Crawford rule game, it is correct for the trailing player to double at the earliest opportunity because the loss of the game, doubled or not, also means the loss of the match. See also: free drop. Market Gainer Any sequence of two rolls (one by a player and one by his opponent) which leads to a position where the opponent would be willing to accept if he were offered a double. Knowing the number of market gainers can help a player decide whether he should double or play on for a gammon. Market Loser Any sequence of two rolls (one by a player and one by his opponent) which leads to a position in which the opponent is no longer be willing to accept if he is offered a double. (Also known as a market-losing sequence.) Knowing the number of market losers can help a player decide whether he should double now or wait. Match A series of games between two players which ends when one player wins by accumulating the required number of points. See also: match play. Match Equity A player's expectation of winning a match at a given match score. The value of a position in the context of the current match score. Match Equity Table A table showing a player's expectation of winning a match from various match scores. Match Play The competition system used in tournaments in which two participants play a series of games which ends when one player accumulates a required number of points. Each game is worth one, two, or three points (for a single game, gammon, or backgammon) multiplied by the value of the doubling cube. Compare: money play. Match Point A match score in which the leading player needs just one more point to win. Mid Point A player's thirteen point. Mixed Roll Two thrown dice with different numbers on their upper face. Compare: doubles. Modern Game A style of play popularized in the 1970s which emphasizes slotting, making advanced anchors, and playing back games. Money Play The normal style of competition in which games are played independently and the competitors bet on the result. For each game, the loser pays the winner the agreed initial stake multiplied by the value of the doubling cube and further multiplied by two for a gammon or three for a backgammon. Compare: match play. Move The advancement of a player's checker according to the value showing on one of the dice he rolls. There are three types of legal moves. A player may: Enter a checker from the bar. (When a player has a checker on the bar, this is his only legal move.) Move a checker the number of pips indicated on the die to a lower open point, possibly hitting an opposing blot. Bear off a checker, if all of the player's checkers are in his home board. Mutual Holding Game A game in which both players occupy a point or points on the opponent's side of the board to make it more difficult for the other player to bring home his checkers safely. MWC Match winning chances. N Neil's Numbers A mnemonic device invented by Neil Kazaross for estimating match equity based on the current match score. It says that the leader's percent probability of winning the match is 50 + his lead multiplied by the Neil's Number. Points trailer needs: 3 4 5 6 7 8 9 10 11 12 13 14 15 Neil's Number: 10 9 8 7 6 5 4 See also: Janowski's Formula. Normalized Match Score A match score expressed in terms of the number of points each player still needs to win the match, as opposed to the number of points they have won so far. Nullo Play A play which cannot be profitable for any possible sequence of future rolls. O On Roll The player who, after his opponent has just completed a turn, is ready to throw the dice to start his own turn. The only time a player may double is when he is on roll. Opening Roll The first roll of a game, in which both players each throw one die. Open Point A position on the board not occupied by two or more of the opposing player's checkers. Otter An immediate redouble (while retaining ownership of the cube) by the player who just accepted a raccoon. Outer Board The side of the board away from where the players bear off their checkers. Each player's outer board comprises that player's points seven through twelve. See also: home board. Outer Table Outer board. Outfield The outer board, particularly points nine, ten, and eleven. Outside Prime A contiguous sequence of blocked points in which the majority of those points are in the outer board. Own the Cube To be the most recent player of the current game to have accepted a double, and the only player who may offer the next double. P Pass Refuse a double. Pick and Pass To hit a blot and then duck for cover using the same checker in the same play. Pip One of the dots on dice that indicate numeric value. A unit of distance on a backgammon board corresponding to the difference in point numbers. For example, the thirteen point and the seven point are six pips apart. Pip Count A count of the total number of points (or pips) that a player must move his checkers to bring them home and bear them off. For example, at the start of the game each player has a pip count of 167: Two checkers on twenty-four point: 2 x 24 = 48 Five checkers on thirteen point: 5 x 13 = 65 Three checkers on eight point: 3 x 8 = 24 Five checkers on six point: 5 x 6 = 30 --- 167 Play The collection of moves a player makes in satisfying the requirements of a roll. Point One of the twenty-four narrow triangles, twelve on each side of a backgammon board, where the players' checkers sit. The points are numbered for each player 1 to 12 across the near side of the board and 13 to 24 in the other direction across the far side of the board. Either player's one point is the other player's twenty-four point. Make a point. To place two or more of your own checkers together at one position (or point), creating a block which cannot be hit. Point on a blot. To hit an opposing blot with two checkers at once, thereby also "making the point." Pointing on a blot in your own home board is usually a very strong play. A unit of scoring in match play. Each game is worth 1, 2, or 3 points (for a regular win, a gammon, or a backgammon) multiplied by the value of the doubling cube. Possession of the Doubling Cube The sole right to offer the next double. A player obtains possession of the doubling cube when he accepts a double from his opponent, at which point only he may make the next double. Pressure To advance a runner so it directly bears on an opponent's blot, forcing the opponent to cover the blot, move it, or risk it being hit. Prime Six consecutive blocks, which together effectively prevent passage of the opponent's checkers. Several consecutive blocks, such as a 4-prime or 5-prime. Prop, or Proposition A prearranged position played several times, usually for money, as a means of settling a dispute over which checker play or cube action is best. Pure Play Checker placement directed towards eventually making a prime, even if it means taking risks. This includes bringing builders down from the mid point, and slotting to make key points quickly. Pure Race A game which has reached the point where it is no longer possible for either player to hit or block the opponent. Q Quadrant One quarter of the playing area on a backgammon board. The first quadrant comprises a player's points 1 to 6, the second quadrant points 7 to 12, the third quadrant points 13 to 18, and the fourth quadrant points 19 to 24. R Raccoon An immediate redouble by the player who just accepted a beaver. Race A position in which it is no longer possible for either player to hit or block the other, as compared to a position of contact. The relative standing of the players' pip counts. A player with a lower pip count is said to be ahead in the race. Recirculate To intentionally allow a blot to be hit for the purpose of gaining time to preserve other valuable points. Recube Vig, or Recube Vigorish The value of cube ownership to the player being offered a double. Redouble A double other than the first double of a game. Only a player who owns the cube may redouble. Reenter Enter. Reference Position A position of known value used as a guide in assessing the value of similar positions. Refuse a Double To resign a game at the current stakes rather than continue to play at twice the stakes, after the opponent offers a double. Compare: Accept a double. Roll a Prime To make a new point at the leading edge of a prime using checkers from the rear of the prime. Roll Out To analyze a position by repeatedly playing it to a later point in the game using different dice rolls. To estimate the equity of a position by playing to completion the same position many times using different random dice rolls and averaging the results (often using a computer). Such an estimate is called a rollout. Root Number A particular roll of the dice which causes a position to crunch. Run To move a checker, particularly the player's last checker, from the opponent's home board. Runner A checker on the bar or in the opponent's home board. Running Game The final stage of a backgammon game when the two forces have passed each other and have no further contact. The strategy employed by a player who is significantly ahead in the race and tries to bring his checkers home and bear them off with little or no interaction with the opponent. (Also called a forward game.) Compare: back game. S Save Gammon To avoid losing a gammon. Semiactive Builder A checker which may or may not be available to make another point, depending on the roll. Settlement A payment of points by one player to the other based on the fair value of a position. See also: equity. Sheshbesh A Middle Eastern variant of backgammon. Shift Points To give up one point in order to make an adjacent point. Shot An opportunity to hit an adverse blot. A direct shot is an opportunity to hit using a single number. An indirect shot is an opportunity to hit using both numbers of the dice played with the same checker. A particular roll of the dice which could hit an enemy blot. Shut Out Close out. Slot To leave a single checker exposed on a point the player wishes to make, with the intention of covering the blot on the next turn. Single Game A completed game which is not a gammon or a backgammon -- either a game in which the losing player has borne off at least one checker or a game that ends when a double is refused. Spare Checker An extra checker that can be used for hitting or making a point without leaving behind a blot. Split To separate two checkers which are together on a point (typically the twenty-four point) and leave them as blots. Squeeze To take advantage of the opponent's compulsion to move any playable roll. Stake The amount wagered by the participants in a game of backgammon. The current stake is the initial stake multiplied by the value of the doubling cube. Stakes Play Money play. Steam To lose control and be prone to bad checker plays or reckless cube decisions, perhaps as a result of a series of unlucky dice rolls. This may become a self-reinforcing situation: as the bad plays accumulate, the steamer views the resulting bad positions as more evidence of unfairness. Stretched A position barren of spare checkers or builders and thus prone to awkward numbers. Strip a Point To remove all but two checkers from a point. Stripped A position barren of spare checkers or builders and thus prone to awkward numbers. Shift Points To give up one point in order to make another. Sydney The roll of 1 and 6 to escape a prime, usually from the bar and often hitting a blot. T Tailgate To start throwing your dice before the opponent has picked up his dice to finish his turn. Take Accept a double. Take/Drop Decision The choice of whether to accept or refuse a double. TD-Gammon A computer program that plays backgammon, written by Gerald Tesauro. Tempo A unit of time in positional development equal to half a roll. Tempo Move A hit designed to forestall the opponent by depriving him of half a roll when he threatens to hit a blot or make an important point. Thorp Count A formula devised by Edward O. Thorp for making doubling decisions in pure race games. It is a modification of the basic pip count which takes into account some elements of checker distribution. Each player's Thorp count is his pip count, plus 2 for each of his checkers still on the board, minus 1 for each of his occupied home board points, plus 1 for each checker on his one point. Then the player on roll increases his count by 10 percent if it is more than 30. Thorp advises: Double any time your count does not exceed the opponent's by more than 2. Redouble any time your count does not exceed opponent's by more than 1. Accept if your count does not exceed doubler's by more than 2. Timing The general rate of advancement of a player's and the opponent's checkers viewed in terms of their likely position at a future crucial point in the game, partially controllable by the leaving of blots to be hit and the hitting or not hitting of adverse blots. Too Good to Double A position in which a player should not double even though the opponent has a clear drop, because the player has a higher equity by playing on for a gammon. Trap Play A deliberate attempt to squeeze the opponent off of his anchor, so that the trapper can close out any blots thereby exposed and win a gammon. Tric-Trac The name for backgammon in many languages including French and Russian. Triple Game Backgammon. Turn The sequence of actions that each player takes in alternation, which consists of: possibly offering a double; rolling the dice; playing the roll; and picking up the dice. Turn the Cube To offer a double. U Under the Gun A blot in the opponent's home board when it is within direct range of three or more of the opponent's builders and therefore in danger of being pointed on. V Vig, or Vigorish A charge taken by a gambling house on bets. The small additional considerations that affect the total equity of a position, such as gammon vigorish and recube vigorish. Volatility The changeability of the equity of a position. A position of high volatility is one that is likely to see a large change in equity as a result of the player's or the opponent's next roll. A position's volatility is a consideration for a player deciding whether or not to offer a double. W Wash A blitzing technique that involves breaking a higher home-board point in order to hit a blot on a lower home-board point. Wastage The expected loss in pips from dice rolls which are not fully used during bearoff. White One of the participants in a backgammon game, presumably the one using lighter-colored checkers. Also, the checkers used by this player. X Y Z Credits This glossary was compiled and edited by Tom Keith. A number of other people have contributed definitions. These include: William Bitting Peter Hurley Mel Leifer Lou Poppler Brian Sheppard Walter Swan Carl Tait Stephen Turner Thanks to all! If you have a comment or suggestion, please write to tom@bkgm.com. Return to: Backgammon Galore