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| XGID=-ABBBBBAA---b----bBb-bcbb-:0:0:1:63:0:0:0:0:10 | |||||
| Blue to play 63 | |||||
| 1. | Rollout1 | 7/1 6/3 | eq: -0.3847 | |||
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| 2. | Rollout1 | 8/2 6/3 | eq: -0.4038 (-0.0190) | |||
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| 3. | Rollout2 | 7/1 5/2 | eq: -0.4067 (-0.0220) | |||
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| 4. | Rollout2 | 8/5 7/1 | eq: -0.4141 (-0.0294) | |||
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| 1 31104 Games rolled with Variance Reduction. Dice Seed: 55907283 Moves: 3-ply, cube decisions: XG Roller 2 15552 Games rolled with Variance Reduction. Dice Seed: 55907283 Moves: 3-ply, cube decisions: XG Roller | ||||||
Rollout by Taper_Mike |
eXtreme Gammon Version: 2.10
Timing Is Everything
Blue needs to recognize how close the timing is. His best opportunity to hit will not be on his next turn. It will be on the turn after, his second turn from now. On his third turn, there may also be some hitting opportunities, but by then, Blue will probably have busted up his board a little more. Hits delayed hits will not be as effective as the ones he gets on his second turn from now.
Suppose Blue decides not to save a 6. Then his best play is J (Jump) = 8/5 7/1. What is his plan for the next turn? He needs to hold his anchor, of course, because White probably won’t be leaving any blots next turn. So that means Blue is planning to play on his side of the board, where his only spare will be on the 5pt. He will have 4 pips he can play before he breaks a point. 31, 21, and 11 are the only rolls he will be able to play without cracking. Worse, all of his 6s except 66, will force him off his anchor, and he will be the one leaving shots instead of White.
You can see from this analysis that if Blue does not break his 6pt on this turn, he is planning, even hoping, that his 6pt will be the point he has to break next turn. He surely does not want to break his anchor. Once you understand that, then the right play is obvious. Blue should play A (Attack) = 7/1 6/3, which leaves him a safe 6 to play next turn. With both play J and play A, Blue is planning to abandon his 6pt before the hitting begins. With play J, however, he may be forced to break his anchor instead.
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| XGID=-ABBBBBAA---b-----Bd-bcbb-:0:0:1:63:0:0:0:0:10 | |||||
| Blue to play 63 | |||||
| 1. | Rollout1 | 7/1 6/3 | eq: -0.3691 | |||
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| 2. | Rollout1 | 8/5 7/1 | eq: -0.3699 (-0.0009) | |||
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| 3. | Rollout2 | 8/2 7/4 | eq: -0.4084 (-0.0394) | |||
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| 1 62208 Games rolled with Variance Reduction. Dice Seed: 97355192 Moves: 3-ply, cube decisions: XG Roller 2 5184 Games rolled with Variance Reduction. Dice Seed: 97355192 Moves: 3-ply, cube decisions: XG Roller | ||||||
Rollout by Taper_Mike |
eXtreme Gammon Version: 2.10
Petter’s Variant
In the OP, Blue does not expect any action on his next turn. If White leaves a shot, it will likely occur on the second or third turn from now. Since Blue won’t be able to hold his board anyway, it makes sense to crack it now, and save a 6 for next turn.
In Petter’s variant, all the action is moved up by one turn or so. White is already leaving shots on any 6 except 66. If he doesn’t leave a shot next turn, he might on the second or third turn from now.
White’s ten shot-leaving 6s gives Blue a strong motivation to make a closed board now, by playing J = 8/5 7/1, and take his chances later. If White rolls small, Blue is not favored to roll a 6 himself, so he may still be able to hold his anchor by breaking his 6pt at that time.
On the other hand, White is not favored to roll a 6 either. In most variations, White’s blots appear after his next turn. By then, either Blue will have broken his anchor, or else Blue’s closed board will be gone. The lesser evil would be to lose the board, so once again there is a strong case for breaking the board now with A = 7/1 6/3, and saving a 6 for next turn.
The two plays are tied in the rollout. Over the board, I would have closed the board.
Mike