          
 
         
 | | White is Player 2
score: 0
pip: 156 | | Unlimited Game | pip: 137
score: 0
Blue is Player 1 |
|
| XGID=-aBa--EBB---dB---bbcb--AA-:0:0:1:31:0:0:0:0:10 |
| Original Position |
| 1. | Rollout1 | 24/21 23/22 | eq: -0.370 |
| Player:
Opponent: | 40.46% (G:13.35% B:0.61%)
59.54% (G:18.33% B:0.79%) | Conf.: ± 0.013 (-0.383...-0.357) - [100.0%]
Duration: 5 minutes 58 seconds |
|
| 2. | Rollout1 | 8/5 6/5 | eq: -0.483 (-0.113) |
| Player:
Opponent: | 37.28% (G:13.51% B:0.43%)
62.72% (G:18.23% B:0.99%) | Conf.: ± 0.015 (-0.498...-0.469) - [0.0%]
Duration: 5 minutes 39 seconds |
|
| 3. | Rollout1 | 23/22 6/3* | eq: -0.492 (-0.122) |
| Player:
Opponent: | 37.55% (G:13.53% B:0.53%)
62.45% (G:18.15% B:1.09%) | Conf.: ± 0.015 (-0.507...-0.477) - [0.0%]
Duration: 5 minutes 57 seconds |
|
| 4. | Rollout2 | 6/3* 3/2 | eq: -0.582 (-0.212) |
| Player:
Opponent: | 35.08% (G:12.87% B:0.44%)
64.92% (G:18.86% B:0.98%) | Conf.: ± 0.015 (-0.597...-0.567) - [0.0%]
Duration: 6 minutes 06 seconds |
|
| |
1 1296 Games rolled with Variance Reduction.
Dice Seed: 271828
Moves: 3-ply, cube decisions: XG Roller
2 1296 Games rolled with Variance Reduction.
Dice Seed: 52672062
Moves: 3-ply, cube decisions: XG Roller
|
Before Tim posted his rollout, I prepared some variants. As it happened, one of my variants (#3 below) is a pip different from his (and with a different result).
Above is Tim's rollout of his original position. Best by far is U (Up, 24/21 23/22).
Below, in my Variant 1, White owns her 9pt instead of her 8pt. Best by far is P (Point, 8/5 6/5).
In Variant 2, White is altered (from the original) by 13/9. Best by far is X (hit and split, 23/22 6/3*).
In Variant 3, one of White's checkers is moved back a pip and the other forward a pip (same pipcount). Demonstrably best is L (Lift, 6/3*/2).
Summary: In the four very similar positions posted here, there are four thematically different best plays: U, P, X and L.
As a bonus, at the bottom of this post I've added a loosely related position that appears in a random book published by a couple of obscure authors 17 years ago.
| | White is Player 2
score: 0
pip: 158 | Unlimited Game
Jacoby Beaver | pip: 137
score: 0
Blue is Player 1 |
|
| XGID=-aBa--EBB---dB--b-bcb--AA-:0:0:1:31:0:0:3:0:10 |
| Variant 1 (White has 9pt instead of 8pt) |
| 1. | Rollout1 | 8/5 6/5 | eq: -0.270 |
| Player:
Opponent: | 42.23% (G:16.39% B:0.51%)
57.77% (G:16.00% B:0.89%) | Conf.: ± 0.015 (-0.284...-0.255) - [100.0%]
Duration: 9 minutes 42 seconds |
|
| 2. | Rollout1 | 24/21 23/22 | eq: -0.348 (-0.079) |
| Player:
Opponent: | 41.22% (G:14.52% B:0.64%)
58.78% (G:18.22% B:0.86%) | Conf.: ± 0.016 (-0.364...-0.332) - [0.0%]
Duration: 9 minutes 52 seconds |
|
| 3. | Rollout1 | 24/23 6/3* | eq: -0.350 (-0.080) |
| Player:
Opponent: | 40.17% (G:14.70% B:0.61%)
59.83% (G:17.08% B:0.94%) | Conf.: ± 0.016 (-0.366...-0.334) - [0.0%]
Duration: 10 minutes 08 seconds |
|
| 4. | Rollout1 | 6/3* 3/2 | eq: -0.369 (-0.100) |
| Player:
Opponent: | 39.49% (G:15.41% B:0.62%)
60.51% (G:16.91% B:0.89%) | Conf.: ± 0.016 (-0.386...-0.353) - [0.0%]
Duration: 10 minutes 09 seconds |
|
| 5. | Rollout1 | 23/22 6/3* | eq: -0.398 (-0.129) |
| Player:
Opponent: | 39.17% (G:14.88% B:0.62%)
60.83% (G:18.02% B:1.10%) | Conf.: ± 0.016 (-0.414...-0.383) - [0.0%]
Duration: 9 minutes 27 seconds |
|
| |
1 1296 Games rolled with Variance Reduction.
Dice Seed: 43316907
Moves: 3-ply, cube decisions: XG Roller
|
| | White is Player 2
score: 0
pip: 152 | Unlimited Game
Jacoby Beaver | pip: 137
score: 0
Blue is Player 1 |
|
| XGID=-aBa--EBB---cB--abbcb--AA-:0:0:1:31:0:0:3:0:10 |
| Variant 2 (White has added 13/9) |
| 1. | Rollout1 | 23/22 6/3* | eq: -0.549 |
| Player:
Opponent: | 35.81% (G:13.24% B:0.73%)
64.19% (G:20.34% B:1.30%) | Conf.: ± 0.014 (-0.563...-0.535) - [100.0%]
Duration: 36 minutes 25 seconds |
|
| 2. | Rollout1 | 24/21 23/22 | eq: -0.600 (-0.051) |
| Player:
Opponent: | 34.36% (G:11.15% B:0.49%)
65.64% (G:21.18% B:0.96%) | Conf.: ± 0.016 (-0.615...-0.584) - [0.0%]
Duration: 37 minutes 37 seconds |
|
| 3. | Rollout1 | 8/5 6/5 | eq: -0.613 (-0.064) |
| Player:
Opponent: | 34.15% (G:12.65% B:0.40%)
65.85% (G:20.25% B:1.27%) | Conf.: ± 0.023 (-0.636...-0.590) - [0.0%]
Duration: 36 minutes 41 seconds |
|
| 4. | Rollout1 | 6/3* 3/2 | eq: -0.615 (-0.066) |
| Player:
Opponent: | 33.74% (G:12.79% B:0.56%)
66.26% (G:19.32% B:1.12%) | Conf.: ± 0.013 (-0.629...-0.602) - [0.0%]
Duration: 35 minutes 17 seconds |
|
| |
1 1296 Games rolled with Variance Reduction.
Dice Seed: 32047511
Moves: 3-ply, cube decisions: XG Roller
|
| | White is Player 2
score: 0
pip: 156 | Unlimited Game
Jacoby Beaver | pip: 137
score: 0
Blue is Player 1 |
|
| XGID=-aBa--EBB---dB---c-db--AA-:0:0:1:31:0:0:3:0:10 |
| Variant 3 (White adj. by 7/6 and 7/8, same pipcount) |
| 1. | Rollout1 | 6/3* 3/2 | eq: -0.1028 |
| Player:
Opponent: | 46.49% (G:17.17% B:0.79%)
53.51% (G:16.23% B:0.76%) | Conf.: ±0.0076 (-0.1104...-0.0952) - [99.7%]
Duration: 2 hours 16 minutes |
|
| 2. | Rollout1 | 8/5 6/5 | eq: -0.1179 (-0.0151) |
| Player:
Opponent: | 45.97% (G:17.54% B:0.59%)
54.03% (G:16.28% B:0.98%) | Conf.: ±0.0074 (-0.1253...-0.1106) - [0.3%]
Duration: 2 hours 07 minutes |
|
| 3. | Rollout2 | 23/22 6/3* | eq: -0.1456 (-0.0427) |
| Player:
Opponent: | 45.68% (G:17.26% B:0.77%)
54.32% (G:16.89% B:0.98%) | Conf.: ±0.0153 (-0.1609...-0.1302) - [0.0%]
Duration: 19 minutes 30 seconds |
|
| 4. | Rollout2 | 24/21 23/22 | eq: -0.2220 (-0.1192) |
| Player:
Opponent: | 44.28% (G:15.65% B:0.82%)
55.72% (G:17.72% B:0.74%) | Conf.: ±0.0143 (-0.2363...-0.2077) - [0.0%]
Duration: 18 minutes 37 seconds |
|
| |
1 5184 Games rolled with Variance Reduction.
Dice Seed: 9755988
Moves: 3-ply, cube decisions: XG Roller
2 1296 Games rolled with Variance Reduction.
Dice Seed: 9755988
Moves: 3-ply, cube decisions: XG Roller
|
Finally, below is 64P-32Z-31, position A86 analyzed in Backgammon Openings (Ballard/Weaver, 2007), along with a contrasting position (A90, not shown here) 64P-63S-31.
Nack
   
| | White is Player 2
score: 0
pip: 162 | Unlimited Game
Jacoby Beaver | pip: 157
score: 0
Blue is Player 1 |
|
| XGID=-aBa--D-B---dE-a-c-e----B-:0:0:1:31:0:0:3:0:10 |
| 64P-32Z-31 |
eXtreme Gammon Version: 2.10