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| Magriel's NYT Columns |
Often in backgammon the game reaches a critical position in which the outcome will be decided in the next few rolls. In such positions accurate tactical play is essential. A key ingredient for precise tactics is an awareness of specifically which numbers are good for your opponent each roll.
In the diagrammed position, Black had doubled several rolls ago but failed to improve his position. Furthermore, the roll of 3-1 is a disappointment — Black had hoped for a 5 with which to hit White’s blot (exposed man) on the 18-point. Indeed, with this roll, Black is unable even to safety his own blot on the 13-point.
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| Black to play 3-1. |
Before making this play, however, Black must examine the placement of all of White’s men. Next roll, White has other objectives besides hitting Black — White also wishes to cover his man on the 18-point and so form a strong five-point prime (from the 22-point to the 18-point). This prime would blockade Black’s two back men (on the 23-point) and significantly reduce Black’s chance to win.
Black is aware that to make the 18-point White needs a direct 4. This observation opens up new tactical possibilities. For example, Black might consider leaving his blot on the 13-point. By remaining there, Black puts White in a position in which White needs a direct 4-shot to hit — the same number, 4, that White needs to cover. Black is said to have “duplicated” White’s good numbers: 4’s to hit and 4’s to cover. Notice that if Black plays 13/10 he would allow White to hit with 1’s or to cover with 4’s. Thus, White would have a much better chance for a favorable roll.
Black has an imaginative way of applying the same logic and carrying it one step further. The correct play is 7/4, 5/4, making the 4-point but giving up the 5-point.
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Rollout
![]() Tom Keith 2013 |
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Money play Centered cube Black rolls 3-1 1296 games with VR Checker play: 2-ply Cube play: 3-ply Red |
| 3-1: | Game | G | BG | Equity | ||||
| 1 | 13/10, 7/6 |
W L |
.4880 .5120 |
.1681 .1476 |
.0170 .0068 | −0.0290 |
| (a) |
| 2 | 13/12, 7/4 |
W L |
.4761 .5239 |
.1434 .1848 |
.0112 .0105 | −0.1222 | (0.0932) | |
| 3 | 7/4, 5/4 |
W L |
.4759 .5241 |
.1437 .1896 |
.0111 .0108 | −0.1275 | (0.0985) | (b) |
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