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Advanced Backgammon #99  Rollout and Variants
Posted By: Igor
Date: Tuesday, 29 April 2014, at 6:12 p.m.
In Response To: Advanced Backgammon #99 (Igor)
This is a huge pass; a four prime is a pretty weak weapon against an anchor at the edge of it.
White is Player 2
score: 0
pip: 153Unlimited Game
Jacoby Beaverpip: 124
score: 0
Blue is Player 1XGID=aaBBBCBcBbccbB:0:0:1:00:0:0:3:0:10 Blue on roll, cube action?
Analyzed in Rollout No double Double/Take Player Winning Chances: 68.97% (G:38.55% B:1.12%) 69.82% (G:45.83% B:0.80%) Opponent Winning Chances: 31.03% (G:6.00% B:0.29%) 30.18% (G:6.68% B:0.35%) Cubeless Equities +0.713 +1.585 Cubeful Equities No double: +0.826 (0.174) ±0.009 (+0.818..+0.835) Double/Take: +1.344 (+0.344) ±0.018 (+1.326..+1.362) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.
Dice Seed: 46610111
Moves: 3ply, cube decisions: XG RollerDouble Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 3 minutes 34 seconds eXtreme Gammon Version: 2.10
Now to the variants. With white off the bar and anchored on the ace point it's not even a double. White has both solid structure and timing.
White is Player 2
score: 0
pip: 152Unlimited Game
Jacoby Beaverpip: 124
score: 0
Blue is Player 1XGID=bBBBCBcBbccbB:0:0:1:00:0:0:3:0:10 Blue on roll, cube action?
Analyzed in Rollout No double Double/Take Player Winning Chances: 60.89% (G:20.39% B:1.42%) 61.32% (G:20.05% B:1.36%) Opponent Winning Chances: 39.11% (G:8.19% B:0.35%) 38.68% (G:7.92% B:0.31%) Cubeless Equities +0.351 +0.717 Cubeful Equities No double: +0.480 ±0.016 (+0.464..+0.496) Double/Take: +0.421 (0.059) ±0.019 (+0.403..+0.440) Double/Pass: +1.000 (+0.520) Best Cube action: No double / Take Percentage of wrong pass needed to make the double decision right: 9.2% Rollout details 1296 Games rolled with Variance Reduction.
Dice Seed: 46610111
Moves: 3ply, cube decisions: XG RollerDouble Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 5 minutes 29 seconds eXtreme Gammon Version: 2.10
White off the bar but not anchored is double and take. Blue has 11 checkers in the zone for quite a few gammons, but white's solid forward structure wins just enough single games to take.
White is Player 2
score: 0
pip: 150Unlimited Game
Jacoby Beaverpip: 124
score: 0
Blue is Player 1XGID=aBaBBCBcBbccbB:0:0:1:00:0:0:3:0:10 Blue on roll, cube action?
Analyzed in Rollout No double Double/Take Player Winning Chances: 63.98% (G:34.72% B:0.91%) 64.37% (G:37.55% B:0.85%) Opponent Winning Chances: 36.02% (G:7.92% B:0.39%) 35.63% (G:8.04% B:0.39%) Cubeless Equities +0.553 +1.174 Cubeful Equities No double: +0.633 (0.256) ±0.012 (+0.621..+0.645) Double/Take: +0.889 ±0.018 (+0.871..+0.907) Double/Pass: +1.000 (+0.111) Best Cube action: Double / Take Rollout details 1296 Games rolled with Variance Reduction.
Dice Seed: 46610111
Moves: 3ply, cube decisions: XG RollerDouble Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 4 minutes 21 seconds eXtreme Gammon Version: 2.10
With five prime it's a big no double.
White is Player 2
score: 0
pip: 158Unlimited Game
Jacoby Beaverpip: 124
score: 0
Blue is Player 1XGID=aaBBBCBcBbbbbbB:0:0:1:00:0:0:3:0:10 Blue on roll, cube action?
Analyzed in Rollout No double Double/Take Player Winning Chances: 56.12% (G:33.12% B:0.76%) 56.08% (G:33.70% B:0.68%) Opponent Winning Chances: 43.88% (G:8.52% B:0.35%) 43.92% (G:8.82% B:0.38%) Cubeless Equities +0.373 +0.747 Cubeful Equities No double: +0.482 ±0.017 (+0.465..+0.499) Double/Take: +0.377 (0.105) ±0.023 (+0.354..+0.400) Double/Pass: +1.000 (+0.518) Best Cube action: No double / Take Percentage of wrong pass needed to make the double decision right: 14.4% Rollout details 1296 Games rolled with Variance Reduction.
Dice Seed: 46610111
Moves: 3ply, cube decisions: XG RollerDouble Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 5 minutes 44 seconds eXtreme Gammon Version: 2.10
If one checker escapes, it's a pass.
White is Player 2
score: 0
pip: 158Unlimited Game
Jacoby Beaverpip: 116
score: 0
Blue is Player 1XGID=aaBBBCBcCbbbbbA:0:0:1:00:0:0:3:0:10 Blue on roll, cube action?
Analyzed in Rollout No double Double/Take Player Winning Chances: 67.66% (G:40.06% B:0.76%) 67.61% (G:41.59% B:0.70%) Opponent Winning Chances: 32.34% (G:5.00% B:0.26%) 32.39% (G:5.34% B:0.23%) Cubeless Equities +0.709 +1.439 Cubeful Equities No double: +0.795 (0.205) ±0.008 (+0.786..+0.803) Double/Take: +1.172 (+0.172) ±0.019 (+1.153..+1.191) Double/Pass: +1.000 Best Cube action: Double / Pass Rollout details 1296 Games rolled with Variance Reduction.
Dice Seed: 89485189
Moves: 3ply, cube decisions: XG RollerDouble Decision confidence: 100.0% Take Decision confidence: 100.0% Duration: 3 minutes 53 seconds eXtreme Gammon Version: 2.10
Finally, a variant due to Robert: shifting blue anchor back one point  will be posted later today when the rollout completes.

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