In his excellent book In the Game Until the End about the coup classique, Bob Wachtel uses the term "semi-run" to describe plays that don't quite guarantee you'll save the backgammon but that reduce your backgammon losses by moving your back checker(s). As I recall, most if not all the semi-run plays he examined did not roll out on top. Of course, Wachtel's book focuses on money play and does not consider scores such as the one here, where White's backgammon value is elevated. According to the rollouts below, Blue should semi-run ATS but not for money.
XG 3-ply doesn't play positions like this one very well, so with perfect play, Blue's equity after staying is probably higher than what the rollout below suggests. However, it seems likely to me that the semi-run is the perfect play here.
I haven't bothered to roll out all the plausible plays because many of them are essentially equivalent.
       
 
       
 | | White is Player 2
score: 0
pip: 8 | 7 point match
Crawford | pip: 128
score: 6
Blue is Player 1 |
|
| XGID=---BBBBBA----AA----A---dA-:0:0:1:42:6:0:1:7:10 |
| Blue to play 42 |
| 1. | Rollout1 | 24/20 8/6 | eq: -1.288 |
| Player:
Opponent: | 0.00% (G:0.00% B:0.00%)
100.00% (G:100.00% B:13.89%) | Conf.: ± 0.000 (-1.288...-1.288) - [100.0%]
Duration: 0.8 second |
|
| 2. | Rollout1 | 24/22 19/15 | eq: -1.322 (-0.034) |
| Player:
Opponent: | 0.00% (G:0.00% B:0.00%)
100.00% (G:100.00% B:16.44%) | Conf.: ± 0.000 (-1.322...-1.322) - [0.0%]
Duration: 1.0 second |
|
| 3. | Rollout1 | 19/17 14/10 | eq: -1.351 (-0.063) |
| Player:
Opponent: | 4.11% (G:0.00% B:0.00%)
95.89% (G:91.78% B:25.49%) | Conf.: ± 0.002 (-1.354...-1.349) - [0.0%]
Duration: 26.3 seconds |
|
| |
1 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
|
eXtreme Gammon Version: 2.19.208.pre-release, MET: Kazaross XG2
Money:
| | White is Player 2
score: 0
pip: 8 | | Unlimited Game | pip: 128
score: 0
Blue is Player 1 |
|
| XGID=---BBBBBA----AA----A---dA-:1:1:1:42:0:0:0:0:10 |
| Blue to play 42 |
| 1. | Rollout1 | 19/17 14/10 | eq: -2.061 |
| Player:
Opponent: | 4.23% (G:0.00% B:0.00%)
95.77% (G:90.61% B:25.98%) | Conf.: ± 0.005 (-2.066...-2.056) - [48.1%]
Duration: 40.4 seconds |
|
| 2. | Rollout1 | 19/15 13/11 | eq: -2.062 (-0.001) |
| Player:
Opponent: | 4.21% (G:0.00% B:0.00%)
95.79% (G:90.55% B:25.98%) | Conf.: ± 0.004 (-2.066...-2.058) - [23.1%]
Duration: 32.5 seconds |
|
| 3. | Rollout1 | 19/13 | eq: -2.063 (-0.002) |
| Player:
Opponent: | 4.16% (G:0.00% B:0.00%)
95.84% (G:90.59% B:25.97%) | Conf.: ± 0.005 (-2.067...-2.058) - [15.6%]
Duration: 33.4 seconds |
|
| 4. | Rollout1 | 19/15 14/12 | eq: -2.063 (-0.002) |
| Player:
Opponent: | 4.14% (G:0.00% B:0.00%)
95.86% (G:90.59% B:25.97%) | Conf.: ± 0.004 (-2.067...-2.059) - [13.3%]
Duration: 26.2 seconds |
|
| 5. | Rollout1 | 24/18 | eq: -2.139 (-0.078) |
| Player:
Opponent: | 0.00% (G:0.00% B:0.00%)
100.00% (G:100.00% B:13.89%) | Conf.: ± 0.000 (-2.139...-2.139) - [0.0%]
Duration: 1.5 seconds |
|
| |
1 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
|
eXtreme Gammon Version: 2.19.208.pre-release