• Run or make the bar point?

    From Timothy Chow@21:1/5 to All on Wed Dec 21 08:24:02 2022
    XGID=--B-bBC-C---cCa---bdc--AA-:0:0:1:61:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O O X X |
    | X O | | O O |
    | X | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X | | X X O X |
    | O X | | X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 142 O: 145 X-O: 0-0
    Cube: 1
    X to play 61

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Wed Dec 21 16:43:56 2022
    On Wednesday, December 21, 2022 at 1:24:04 PM UTC, Tim Chow wrote:
    XGID=--B-bBC-C---cCa---bdc--AA-:0:0:1:61:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O O X X |
    | X O | | O O |
    | X | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X | | X X O X |
    | O X | | X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 142 O: 145 X-O: 0-0
    Cube: 1
    X to play 61

    For the sake of intellectual honesty, I have to go with what I would surely play OTB
    which is to make the bar point. But such a pedestrian play seems most unlikely to
    be correct.
    Look out for a "Trickster Tim" special which neither runs nor makes the bar point but
    does something else entirely -- like provide free cans of salt and vinegar Pringles.

    Paul Epstein

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  • From BlueDice@21:1/5 to Tim Chow on Thu Dec 22 06:03:15 2022
    On Wednesday, December 21, 2022 at 1:24:04 PM UTC, Tim Chow wrote:
    XGID=--B-bBC-C---cCa---bdc--AA-:0:0:1:61:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O O X X |
    | X O | | O O |
    | X | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X | | X X O X |
    | O X | | X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 142 O: 145 X-O: 0-0
    Cube: 1
    X to play 61

    ---
    Tim Chow

    I think that we can assume that making our bar point is not the top play, otherwise the position would hardly be posted.
    However, I would make it without thinking to much OtB.
    So, we are encouraged to look around for alternatives...

    Comparing bar pt with 24/17:
    The largest swing is after opp's 21 in favour of 24/17. There is less discrimination on the other rolls.

    Comparing 24/17 with 23/16
    There are significant swings on opp's 62, 41 & 64 in favour of 24/17. There is less discrimination on the other rolls.

    After all that, 24/17 gets my vote.
    --
    BD

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Fri Dec 23 08:48:25 2022
    XGID=--B-bBC-C---cCa---bdc--AA-:0:0:1:61:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O O X X |
    | X O | | O O |
    | X | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X | | X X O X |
    | O X | | X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 142 O: 145 X-O: 0-0
    Cube: 1
    X to play 61

    The bar point has diminished value when the opponent has an advanced
    anchor. On the other hand, X's back checkers are starting to get a
    bit hemmed in. These factors point to running. Also note that if X
    plays 13/7 8/7, then he has no spare checkers on his outfield points;
    this is what Falafel called an "Island" and is an indicator of poor flexibility.

    In the variant, I have pushed O's anchor back a pip, and the rollout
    indicates a dead heat.

    1. Rollout¹ 24/17 eq:-0.326
    Player: 43.62% (G:8.61% B:0.34%)
    Opponent: 56.38% (G:19.34% B:0.47%)
    Confidence: ±0.014 (-0.340..-0.312) - [100.0%]

    2. Rollout¹ 13/7 8/7 eq:-0.396 (-0.070)
    Player: 41.54% (G:8.67% B:0.32%)
    Opponent: 58.46% (G:17.86% B:0.55%)
    Confidence: ±0.013 (-0.409..-0.383) - [0.0%]

    3. Rollout¹ 23/16 eq:-0.410 (-0.084)
    Player: 41.04% (G:8.35% B:0.32%)
    Opponent: 58.96% (G:18.12% B:0.50%)
    Confidence: ±0.012 (-0.422..-0.398) - [0.0%]

    4. Rollout¹ 23/17 6/5 eq:-0.423 (-0.098)
    Player: 40.89% (G:8.03% B:0.30%)
    Opponent: 59.11% (G:18.84% B:0.53%)
    Confidence: ±0.012 (-0.435..-0.411) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.211.pre-release

    -------
    Variant
    -------

    XGID=--Bb-BC-C---cCa---bdc--AA-:0:0:1:61:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O O X X |
    | X O | | O O |
    | X | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X | | X X O X |
    | O X | | X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 142 O: 147 X-O: 0-0
    Cube: 1
    X to play 61

    1. Rollout¹ 13/7 8/7 eq:-0.208
    Player: 45.71% (G:11.44% B:0.49%)
    Opponent: 54.29% (G:17.48% B:0.63%)
    Confidence: ±0.007 (-0.214..-0.201) - [50.9%]

    2. Rollout¹ 24/17 eq:-0.208
    Player: 46.25% (G:10.74% B:0.46%)
    Opponent: 53.75% (G:19.43% B:0.53%)
    Confidence: ±0.006 (-0.215..-0.202) - [49.1%]

    ¹ 5184 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow

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