• Double from the bar?

    From Timothy Chow@tchow12000@yahoo.com to rec.games.backgammon on Fri Feb 23 09:38:13 2024
    From Newsgroup: rec.games.backgammon

    XGID=-BBaaBC-BC--a-----bc-dab-A:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O O |
    | O | | O O O |
    | | | O O |
    | | | O |
    | | X | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X X X X |
    | O X X | | X X O O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 111 X-O: 0-0
    Cube: 1
    X on roll, cube action

    ---
    Tim Chow
    --- Synchronet 3.21b-Linux NewsLink 1.2
  • From Timothy Chow@tchow12000@yahoo.com to rec.games.backgammon on Sun Feb 25 09:30:57 2024
    From Newsgroup: rec.games.backgammon

    XGID=-BBaaBC-BC--a-----bc-dab-A:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O O |
    | O | | O O O |
    | | | O O |
    | | | O |
    | | X | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X X X X |
    | O X X | | X X O O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 111 X-O: 0-0
    Cube: 1
    X on roll, cube action

    I badly misjudged this position and took this cube. But O has too
    many vulnerable blots, and loses a ton of gammons.

    Analyzed in Rollout
    No double
    Player Winning Chances: 71.08% (G:38.47% B:3.96%)
    Opponent Winning Chances: 28.92% (G:6.26% B:0.18%)
    Double/Take
    Player Winning Chances: 71.25% (G:39.50% B:4.09%)
    Opponent Winning Chances: 28.75% (G:6.61% B:0.21%)

    Cubeful Equities:
    No double: +0.861 (-0.139)
    Double/Take: +1.376 (+0.376)
    Double/Pass: +1.000

    Best Cube action: Double / Pass

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: -# 0.009 (+0.852..+0.870)
    Confidence Double: -# 0.014 (+1.362..+1.390)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---------
    Variant 1
    ---------

    XGID=-BBaaBC-BC--a-----bd-d-b-A:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O |
    | O | | O O O |
    | | | O O |
    | | | O O |
    | | X | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X X X X |
    | O X X | | X X O O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 114 X-O: 0-0
    Cube: 1
    X on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 67.78% (G:28.34% B:1.39%)
    Opponent Winning Chances: 32.22% (G:6.85% B:0.25%)
    Double/Take
    Player Winning Chances: 67.84% (G:30.86% B:1.57%)
    Opponent Winning Chances: 32.16% (G:7.50% B:0.26%)

    Cubeful Equities:
    No double: +0.686 (-0.297)
    Double/Take: +0.983
    Double/Pass: +1.000 (+0.017)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: -# 0.009 (+0.676..+0.695)
    Confidence Double: -# 0.013 (+0.969..+0.996)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---------
    Variant 2
    ---------

    XGID=-BBa-BC-BCa-a-----bc-dab-A:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O O |
    | O | | O O O |
    | | | O O |
    | | | O |
    | | X | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X X X X |
    | O O X X | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 105 X-O: 0-0
    Cube: 1
    X on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 65.25% (G:34.32% B:2.65%)
    Opponent Winning Chances: 34.75% (G:7.40% B:0.21%)
    Double/Take
    Player Winning Chances: 65.31% (G:34.63% B:2.65%)
    Opponent Winning Chances: 34.69% (G:7.33% B:0.19%)

    Cubeful Equities:
    No double: +0.638 (-0.328)
    Double/Take: +0.967
    Double/Pass: +1.000 (+0.033)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: -# 0.009 (+0.629..+0.647)
    Confidence Double: -# 0.023 (+0.944..+0.990)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow
    --- Synchronet 3.21b-Linux NewsLink 1.2