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501 Essential Backgammon Problems #55 -- More Variants

Posted By: Igor
Date: Wednesday, 11 September 2013, at 10:40 p.m.

In Response To: 501 Essential Backgammon Problems #55 (Igor)

For these variants we will play with the position of the two white back checkers.

		White is Player 2 score: 0 pip: 149 Unlimited Game Jacoby pip: 163 score: 0 Blue is Player 1
XGID=--b---E-CBB-b---acbe---AB-:0:0:1:22:0:0:1:0:10
Blue to play 22

1.	Rollout1	24/20(2)	eq: +0.148
	Player: Opponent: 52.72% (G:14.41% B:0.54%) 47.28% (G:10.16% B:0.41%) Conf.: ± 0.010 (+0.138...+0.159) - [100.0%] Duration: 14 minutes 49 seconds
2.	Rollout1	24/22(2) 6/4(2)	eq: +0.118 (-0.031)
	Player: Opponent: 52.25% (G:16.55% B:0.71%) 47.75% (G:12.43% B:0.60%) Conf.: ± 0.011 (+0.107...+0.129) - [0.0%] Duration: 12 minutes 36 seconds
3.	Rollout2	9/7(2) 6/4(2)	eq: +0.083 (-0.065)
	Player: Opponent: 52.35% (G:16.12% B:0.75%) 47.65% (G:15.40% B:1.10%) Conf.: ± 0.015 (+0.068...+0.098) - [0.0%] Duration: 5 minutes 02 seconds
1 2592 Games rolled with Variance Reduction. Dice Seed: 5475556 Moves: 3-ply, cube decisions: XG Roller 2 1296 Games rolled with Variance Reduction. Dice Seed: 5475556 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

This is a surprising result for me; I did not expect that moving white anchor from 24pt to 23pt will effect such a drastic change in blue's strategy.

		White is Player 2 score: 0 pip: 147 Unlimited Game Jacoby pip: 163 score: 0 Blue is Player 1
XGID=---b--E-CBB-b---acbe---AB-:0:0:1:22:0:0:1:0:10
Blue to play 22

1.	Rollout1	24/20(2)	eq: +0.105
	Player: Opponent: 52.15% (G:11.92% B:0.42%) 47.85% (G:9.68% B:0.27%) Conf.: ± 0.014 (+0.091...+0.119) - [100.0%] Duration: 7 minutes 45 seconds
2.	Rollout1	24/22(2) 6/4(2)	eq: +0.060 (-0.045)
	Player: Opponent: 51.70% (G:13.00% B:0.53%) 48.30% (G:12.54% B:0.52%) Conf.: ± 0.015 (+0.045...+0.075) - [0.0%] Duration: 6 minutes 11 seconds
3.	Rollout1	9/7(2) 6/4(2)	eq: -0.286 (-0.392)
	Player: Opponent: 43.83% (G:11.27% B:0.48%) 56.17% (G:17.32% B:1.10%) Conf.: ± 0.016 (-0.302...-0.271) - [0.0%] Duration: 5 minutes 19 seconds
1 1296 Games rolled with Variance Reduction. Dice Seed: 5475556 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

This is expected; it would be difficult to prime the 22pt anchor, so we are better off taking a guaranteed improvement on the other side of the board.

		White is Player 2 score: 0 pip: 150 Unlimited Game Jacoby pip: 163 score: 0 Blue is Player 1
XGID=-aa---E-CBB-b---acbe---AB-:0:0:1:22:0:0:1:0:10
Blue to play 22

1.	Rollout1	9/7(2) 6/4(2)	eq: +0.090
	Player: Opponent: 51.81% (G:17.25% B:0.92%) 48.19% (G:14.87% B:1.01%) Conf.: ± 0.011 (+0.078...+0.101) - [100.0%] Duration: 11 minutes 31 seconds
2.	Rollout1	24/20(2)	eq: +0.061 (-0.028)
	Player: Opponent: 50.62% (G:13.74% B:0.48%) 49.38% (G:10.30% B:0.45%) Conf.: ± 0.011 (+0.051...+0.072) - [0.0%] Duration: 15 minutes 50 seconds
3.	Rollout1	24/22(2) 6/4(2)	eq: +0.041 (-0.049)
	Player: Opponent: 50.08% (G:16.63% B:0.71%) 49.92% (G:13.29% B:0.62%) Conf.: ± 0.012 (+0.029...+0.052) - [0.0%] Duration: 13 minutes 09 seconds
1 2592 Games rolled with Variance Reduction. Dice Seed: 5475556 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

With a minor split for white we are looking to attack.

		White is Player 2 score: 0 pip: 149 Unlimited Game Jacoby pip: 163 score: 0 Blue is Player 1
XGID=-a-a--E-CBB-b---acbe---AB-:0:0:1:22:0:0:1:0:10
Blue to play 22

1.	Rollout1	24/20(2)	eq: +0.102
	Player: Opponent: 51.65% (G:13.92% B:0.51%) 48.35% (G:10.16% B:0.39%) Conf.: ± 0.002 (+0.100...+0.105) - [100.0%] Duration: 4 hours 26 minutes
2.	Rollout1	24/22(2) 6/4(2)	eq: +0.096 (-0.006)
	Player: Opponent: 51.59% (G:16.02% B:0.71%) 48.41% (G:12.33% B:0.55%) Conf.: ± 0.003 (+0.094...+0.099) - [0.0%] Duration: 3 hours 47 minutes
3.	Rollout2	9/7(2) 6/4(2)	eq: -0.069 (-0.172)
	Player: Opponent: 48.39% (G:14.80% B:0.76%) 51.61% (G:15.96% B:1.09%) Conf.: ± 0.018 (-0.087...-0.051) - [0.0%] Duration: 5 minutes 49 seconds
1 46656 Games rolled with Variance Reduction. Dice Seed: 5475556 Moves: 3-ply, cube decisions: XG Roller 2 1296 Games rolled with Variance Reduction. Dice Seed: 5475556 Moves: 3-ply, cube decisions: XG Roller

eXtreme Gammon Version: 2.10

Finally, a variant where the middling play is somewhat competitive. With a better split white has a better chance to get a good anchor, so our priority is to secure a guaranteed asset. Also, the 9pt would be the perfect block for the potential white 22pt anchor.

Messages In This Thread

• 501 Essential Backgammon Problems #55
  Igor -- Saturday, 7 September 2013, at 3:25 p.m.
  • 501 Essential Backgammon Problems #55
    Dmitriy Obukhov -- Saturday, 7 September 2013, at 7:39 p.m.
  • 501 Essential Backgammon Problems #55 -- Rollout + Variants
    Igor -- Tuesday, 10 September 2013, at 6:24 p.m.
    • 501 Essential Backgammon Problems #55 -- Rollout + Variants
      Daniel Murphy -- Tuesday, 10 September 2013, at 9:17 p.m.
      • 501 Essential Backgammon Problems #55 -- Rollout + Variants
        Casper Van der Tak -- Wednesday, 11 September 2013, at 12:15 a.m.
  • 501 Essential Backgammon Problems #55 -- More Variants
    Igor -- Wednesday, 11 September 2013, at 10:40 p.m.