Magriel's NYT Columns |
This is particularly true in positions such as the diagrammed one, in which there is a “battle of primes,” that is, when both sides are blockading each other. Black has two men on the 23-point behind White’s 5-point prime. Meanwhile, Black has his own broken 5-point prime, behind which White has a man trapped on the 1-point.
| Black to play 6-4. |
When Black rolled a 6-4, he had several immediate choices, each of which reflected a different game plan:
- He could simply run with one back man by playing 23/13.
- Another possibility was for him to attack by playing 7/1*, 5/1.
- He could run-and-attack by playing 23/17, 5/1*.
All of these choices, while having desirable features, have serious drawbacks.
23/13 |
7/1*, 5/1 |
23/17, 5/1* |
Similarly, the run-and-attack scheme was potentially even more dangerous — Black would now be playing with four blots (exposed men). In both these cases, Black stood a significant chance of not only losing the game, but of being closed out and gammoned. In the actual tournament situation, because of match-score considerations, Black was particularly reluctant to risk losing a double game (gammon).
Black’s other choice, attacking White and making his 1-point, also had liabilities. If White reentered with a 4, Black would probably lose. More importantly, by not running out with a 6, Black left both back men still trapped behind White’s prime.
Black did not choose any of those three plays — but ingeniously found another approach altogether. He made a waiting move, 9/3, 6/2 and so forced White to move.
Of course, White might escape with 3-4, 3-5, or 3-6; but if White fails to escape, it is likely that he will be forced to break his valuable 5-point prime. If White is allowed to continue moving forward he will be in danger of totally destroying his position. Indeed, 6-5 and 5-4 are immediately “disaster” rolls for White, compelling him to leave a double direct shot.
Black’s game plan of waiting, although passive, was also effective: It gave Black significant winning chances without the danger of being closed out and gammoned.
Rollout
Tom Keith 2013 |
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Money play Black owns 2-cube Black rolls 6-4 1296 games with VR Checker play: 2-ply Cube play: 3-ply Red |
6-4: | Game | G | BG | Equity | ||||
1 | 9/3, 6/2 |
W L |
.4222 .5778 |
.0594 .0793 |
.0024 .0020 | −0.0272 | Wait | |
2 | 23/17, 9/5 |
W L |
.4151 .5849 |
.0578 .1295 |
.0020 .0017 | −0.1040 | (0.0768) | |
3 | 23/13 |
W L |
.4413 .5587 |
.0632 .2154 |
.0022 .0051 | −0.1130 | (0.0858) | Run |
4 | 7/1*, 5/1 |
W L |
.3581 .6419 |
.0182 .1236 |
.0003 .0040 | −0.2705 | (0.2433) | Attack |
5 | 23/17, 6/2 |
W L |
.3909 .6091 |
.0545 .2390 |
.0020 .0057 | −0.2757 | (0.2485) | |
6 | 23/17, 5/1* |
W L |
.4076 .5924 |
.0448 .2772 |
.0013 .0135 | −0.2780 | (0.2508) | Run+Attack |
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