Unwelcome Guests Waiting at the Door
Paul Magriel, 1978
New York Times, April 13, 1978
Guinness World Records The North Shore Backgammon Club in Carle Place is a focal point for backgammon events on Long Island. Steve Kurzbaum, the club’s director, runs tournaments every night of the week except Monday. On the last weekend in March, the club held, for the benefit of the Human Resources Center, a nonstop marathon playing session for a group of players. The object was to see who could last the longest. After 50 hours and 356 games, the three remaining players decided to call it quits.

The diagrammed position is taken from one of the last games of this Gammothon, between top scorers Howard Ehrlich and Alphonse Mekalainas, two of the three holdouts. Ehrlich (Black) has already doubled Mekalainas (White) and has taken four men off. White is sitting on the 2-point, waiting for a last-minute shot to hit Black and salvage the game.

Black to play 3-1.
With the roll of 3-1, Black has several choices. This position is a difficult one, and various factors must be weighed before a decision is made. Black’s top priority, of course, is to plan ahead so that he is not hit by White, who has a formidable home board.
(a) 3/off, 1/off

Obviously, Black could simply take two men off by playing 3/off, 1/off. This move, however, would leave Black with a dangerous gap on the 3-point, with this point vacant, Black would have trouble safely clearing his other points. (A gap in the bearoff is considered a defect. The general principle is that gaps should be avoided when possible; when unavoidable, leave them on the higher points.)

(b) 6/3, 6/5
In the actual game, Ehrlich eliminated the gap on the 3-point by playing 6/3, 6/5, clearing his 6-point and simultaneously remaking his 3-point. Unfortunately, the resulting position contains a defect even more serious than the gap left by the first play.

The single extra man left on the 5-point is troublesome particularly because it is isolated. Next turn, if Black rolls a 5 or a 6 without a 1, he will be forced to leave a shot. In fact, the majority of Black’s numbers (19 combinations out of 36, to be exact) cause Black to leave a man exposed.

(c) 4/3, 4/1
Ehrlich overlooked the correct play, 4/3, 4/1, clearing the 4-point and remaking the 3-point. This move leaves a gap on the 4-point, which is not nearly as dangerous as a gap on the 3-point.

More important, it leaves Black with an even number of men on all his high points. For this reason, this is the safest of the three plays: in fact, only about a quarter of Black’s rolls (10 combinations out of 36) will now force him to leave a shot immediately.

XG logo
Tom Keith 2013 
Money play
White owns 2-cube
Black rolls 3-1

1296 games with VR
Checker play: 2-ply
Cube play: 3-ply Red

3-1: Game BG   Equity
1 3/off, 1/off W
+0.8282 x  (a)
2 6/5, 6/3 W
+0.7702 (0.0580)  (b)
3 4/3, 4/1 W
+0.6675 (0.1607)  (c)

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