Magriel's NYT Columns |
Last weekend, at a tournament in Hasbrouck Heights, an interesting match position arose that later was the subject of much debate. Black, leading 5 to 3 in a 7-point match, had already been doubled. Because he now owned the cube at the 2-level, Black was aware that winning this game would give him the match.
The game had reached a critical juncture when Black rolled a 4-2 in the diagrammed position.
3
MATCH TO 7 5 |
| Black to play 4-2. |
- If White misses (25 chances out of 36), Black will now be the strong favorite to come home safely and easily win the game (and match).
- If White rolls a 3 and hits (11 chances out of 36), Black will be put on the bar against White’s closed home board. Black, unable to move, will be powerless to prevent White from picking up his remaining two blots on the 7- and 13-points. Such a massacre will not only cost Black the game, but will almost certainly result in a gammon (or double game) worth 4 points to White.
The risk of being gammoned and so losing the match at once is unacceptably high. Trying too hard to win this one particular game (by hitting), jeopardizes the overall match chances.
The correct and more prudent play is 5/3, 5/1. This play may allow White to enter a straight race (which will be closely contested) but avoids the possibility of Black’s being gammoned. If White happens to win the race, the score will be tied 5 to 5. Even after Black loses this game, he will still have a 50 percent chance of winning the match. Thus the correct play is not as likely to win the game but gives Black the best chance of winning the match.
Black could also play safe by moving 8/6, 8/4. This play, however, leaves three blots in Black’s home board. As a result, White unafraid of being hit, may cause Black problems by lingering on the 7-point. The correct play, which leaves no blots in Black’s home board makes it undesirable for White to leave himself open in the outfield.
Note that in the regular (nonmatch) game the decision whether to hit is a closer issue because the gammon does not weigh quite so heavily. The same play, 5/3, 5/1, is still preferable for a reason that is not relevant in the match situation described. In the race that will probably result, Black’s advantage will be magnified by the leverage of owning the cube and the consequent threat to redouble.
* * *
This evening the Metropolitan Backgammon Association will conduct the fourth Big Apple Backgammon Championship, with sections for intermediate and advanced players. Final registration will be between 6 and 7:30 P.M. in the Holiday Inn at 440 West 57th Street. Further details about tonight’s tournament or the Jersey Association may be obtained from Dan Caverly, at (201) 785-1574.
Rollout
Tom Keith 2013 |
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Match to 7 White 3, Black 5 Black owns 2-cube Black rolls 4-2 1296 games with VR Checker play: 2-ply Cube play: 3-ply Red |
4-2: | Game | G | BG | Equity | ||||
1 | 5/3, 5/1 |
W L |
.5069 .4931 |
.0009 .0236 |
.0000 .0005 | −0.0334 | (b) | |
2 | 8/6, 8/4 |
W L |
.4874 .5126 |
.0004 .0244 |
.0000 .0011 | −0.0740 | (0.0406) | |
4 | 13/11*/7* |
W L |
.5146 .4854 |
.0435 .2372 |
.0001 .0160 | −0.4452 | (0.4118) | (a) |
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