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Advanced Backgammon #7

Posted By: Igor
Date: Wednesday, 22 January 2014, at 3:41 p.m.

First of all, before I post any positions, I would like to thank David Presser who loaned me his copies of the book; the project would not be possible without David's generosity.

Second, Taper_Mike sent me his archive with all positions already setup in XG and analyzed in XGR++; this saves me time in setting up the positions and also many positions are corrected to be what they should have looked like in the book.

Third, Smcrtorchs is volunteering his CPU time to help me with rollouts; his contribution has already been extremely useful.

So, this has truly become a community project.

Now to the position.

		White is Player 2 score: 0 pip: 159 Unlimited Game Jacoby Beaver pip: 161 score: 0 Blue is Player 1
XGID=-b---AD-D---bDab-c-e----B-:0:0:1:54:0:0:3:0:10
Blue to play 54

eXtreme Gammon Version: 2.10

I reconstructed this position as (albeit, misplayed on the third roll) 32D-51$-21D-54. Here is a rollout of the third move decision white faced (my Nactation skills are atrocious, so there might be errors):

		White is Player 2 score: 0 pip: 161 Unlimited Game Jacoby Beaver pip: 162 score: 0 Blue is Player 1
XGID=-b----E-C-AAdC---d-da---B-:0:0:1:12:0:0:3:0:10
Blue to play 12

1.	Rollout1	11/10 6/4	eq: -0.076
	Player: Opponent: 48.23% (G:14.55% B:0.74%) 51.77% (G:16.05% B:0.93%) Conf.: ± 0.006 (-0.082...-0.070) - [100.0%] Duration: 1 hour 06 minutes
2.	Rollout1	24/22 11/10	eq: -0.092 (-0.016)
	Player: Opponent: 48.16% (G:13.00% B:0.60%) 51.84% (G:15.66% B:0.62%) Conf.: ± 0.006 (-0.098...-0.086) - [0.0%] Duration: 1 hour 09 minutes
3.	Rollout2	11/9 10/9	eq: -0.101 (-0.025)
	Player: Opponent: 47.51% (G:13.71% B:0.66%) 52.49% (G:15.59% B:0.78%) Conf.: ± 0.008 (-0.109...-0.094) - [0.0%] Duration: 33 minutes 20 seconds
1 10368 Games rolled with Variance Reduction. Dice Seed: 11987154 Moves: 3-ply, cube decisions: XG Roller 2 5184 Games rolled with Variance Reduction. Dice Seed: 11987154 Moves: 3-ply, cube decisions: XG Roller

Rollout by Igor Erovenko 2014-Jan-18 eXtreme Gammon Version: 2.10 32D-51$-21-ie.xgp [N S16 P25] "<=10*5

eXtreme Gammon Version: 2.10

The bonus question is how would you play 54 after each of the top three moves for 21.

Messages In This Thread

• Advanced Backgammon #7
  Igor -- Wednesday, 22 January 2014, at 3:41 p.m.
  • Relevant Second Roll Positions
    Paul Weaver -- Wednesday, 22 January 2014, at 4:26 p.m.
    • Relevant Second Roll Positions
      Igor -- Wednesday, 22 January 2014, at 5:04 p.m.
    • 51$-52 [S $1 D14]
      eXtreme Gammon -- Sunday, 26 January 2014, at 8:26 p.m.
      • 51$-52 [S=$] "^46
        Nack Ballard -- Monday, 27 January 2014, at 3:29 a.m.
        • 51$-52 / My 4 ply XG2 RO
          David Rockwell -- Wednesday, 29 January 2014, at 6:24 p.m.
          • 51$-52 — Index to Rollouts
            Taper_Mike -- Thursday, 30 January 2014, at 6:39 p.m.
  • Advanced Backgammon #7
    Keene -- Wednesday, 22 January 2014, at 6:30 p.m.
  • Nactations of 32D-51$-21
    Taper_Mike -- Thursday, 23 January 2014, at 1:27 a.m.
    • Nactations of 32D-51$-21
      Igor -- Thursday, 23 January 2014, at 2:45 a.m.
      • Nactations of 32D-51$-21
        Taper_Mike -- Thursday, 23 January 2014, at 3:48 a.m.
  • Advanced Backgammon #7
    Taper_Mike -- Thursday, 23 January 2014, at 6:23 p.m.
    • Advanced Backgammon #7
      Igor -- Thursday, 23 January 2014, at 6:57 p.m.
      • Advanced Backgammon #7
        Taper_Mike -- Thursday, 23 January 2014, at 7:16 p.m.
  • Advanced Backgammon #7
    David Presser -- Thursday, 23 January 2014, at 6:53 p.m.
  • Advanced Backgammon #7
    Nack Ballard -- Friday, 24 January 2014, at 9:58 a.m.
    • Advanced Backgammon #7
      Igor -- Friday, 24 January 2014, at 4:01 p.m.
  • Advanced Backgammon #7 -- Rollouts
    Igor -- Friday, 24 January 2014, at 4:17 p.m.
    • 32D-51$-21 — No Jacoby, No Beavers — 3-ply XG2 Rollout
      Taper_Mike -- Tuesday, 28 January 2014, at 9:15 p.m.