• A pretty good roll in a pretty bad position

    From Timothy Chow@21:1/5 to All on Wed Nov 9 10:01:56 2022
    XGID=---CBbBAA---------bbFcbbb-:1:1:1:44:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | | | X O |
    | | | X |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | | | X O X X | | 2 |
    | X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 164 O: 90 X-O: 0-0
    Cube: 2, X own cube
    X to play 44

    ---
    Tim Chow

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Wed Nov 9 13:07:53 2022
    On Wednesday, November 9, 2022 at 3:01:59 PM UTC, Tim Chow wrote:
    XGID=---CBbBAA---------bbFcbbb-:1:1:1:44:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | | | X O |
    | | | X |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | | | X O X X | | 2 |
    | X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 164 O: 90 X-O: 0-0
    Cube: 2, X own cube
    X to play 44

    Surely, the "pretty" theme can (and should) be extended here:
    "A pretty easy problem of playing a pretty good roll in a pretty bad position." It's trivial as a quiz but missable OTB, I suppose.
    Very obviously, we have to protect both our blots. This forces 7/3 so we only have 3 fours to play.
    Actually, no, the problem is not easy. I take that back.
    However, I want to preserve my thought processes, so I'm not going to erase my first impression.
    There's a real debate (from my point of view -- it might be obvious to Stick) about whether we
    make the 8 point or play 8/4.
    When I (erroneously) thought the problem was trivial, I thought we could play 20/16 after playing 20/8 but
    no, that's too many fours.
    There seem to be two candidates 8/4 7/3 20/16(2) and 7/3 20/8.
    The QF play is 20/8 because the quizzer (not a point about Tim but someone setting these problems in general)
    is quite likely to want to punish the impulsive (and weak) player who immediately plays 8/4 without thinking of
    the protection play.
    However, I'm more impressed by the outfield point than the 8 point.
    8/4 20/16(2) for me with about 60% confidence only.
    I still think this isn't the QF play but Tim has sometimes claimed to be anti-QF, and this self-assessment sounds
    right to me.

    Paul

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  • From Timothy Chow@21:1/5 to All on Fri Nov 11 10:28:03 2022
    XGID=---CBbBAA---------bbFcbbb-:1:1:1:44:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | | | X O |
    | | | X |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | | | X O X X | | 2 |
    | X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 164 O: 90 X-O: 0-0
    Cube: 2, X own cube
    X to play 44

    Congrats to Paul, who found the bot play of 20/16(2) 8/4 7/3 and also
    observed that this is a pedestrian, anti-QF play. OTB, I tried the
    "fancy" play of 20/8 7/3 and got dinged heavily by XG for it.

    Speaking of QF, XG does favor a QF play at DMP, as indicated by the
    rollout below: 20/16 20/8!

    1. Rollout¹ 20/16(2) 8/4 7/3 eq:-0.585
    Player: 27.90% (G:4.46% B:0.13%)
    Opponent: 72.10% (G:29.89% B:0.35%)
    Confidence: ±0.007 (-0.592..-0.577) - [100.0%]

    2. Rollout¹ 20/16(3) 8/4 eq:-0.641 (-0.056)
    Player: 27.99% (G:4.73% B:0.12%)
    Opponent: 72.01% (G:36.47% B:0.28%)
    Confidence: ±0.008 (-0.649..-0.633) - [0.0%]

    3. Rollout¹ 20/16 20/8 eq:-0.688 (-0.104)
    Player: 28.37% (G:5.34% B:0.17%)
    Opponent: 71.63% (G:42.33% B:0.86%)
    Confidence: ±0.009 (-0.697..-0.680) - [0.0%]

    4. Rollout¹ 20/8 7/3 eq:-0.699 (-0.114)
    Player: 24.44% (G:3.86% B:0.12%)
    Opponent: 75.56% (G:32.56% B:0.53%)
    Confidence: ±0.007 (-0.706..-0.692) - [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

    ---
    DMP
    ---

    XGID=---CBbBAA---------bbFcbbb-:0:0:1:44:0:0:0:1:10

    Score is X:0 O:0 1 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | | | X O |
    | | | X |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | X |
    | | | X O X X |
    | X X | | X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 164 O: 90 X-O: 0-0/1
    Cube: 1
    X to play 44

    1. Rollout¹ 20/16 20/8 eq:-0.416
    Player: 29.22% (G:4.29% B:0.13%)
    Opponent: 70.78% (G:50.44% B:0.84%)
    Confidence: ±0.004 (-0.420..-0.411) - [99.9%]

    2. Rollout¹ 20/16(2) 8/4 7/3
  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Fri Nov 11 07:46:25 2022
    On Friday, November 11, 2022 at 3:28:05 PM UTC, Tim Chow wrote:
    XGID=---CBbBAA---------bbFcbbb-:1:1:1:44:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | | | X O |
    | | | X |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | | | X O X X | | 2 |
    | X X | | X O X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 164 O: 90 X-O: 0-0
    Cube: 2, X own cube
    X to play 44
    Congrats to Paul, who found the bot play of 20/16(2) 8/4 7/3 and also observed that this is a pedestrian, anti-QF play. OTB, I tried the
    "fancy" play of 20/8 7/3 and got dinged heavily by XG for it.

    Speaking of QF, XG does favor a QF play at DMP, as indicated by the
    rollout below: 20/16 20/8!

    Even in the non-variantized originalizationed postingization in the actual quizzation,
    we see the same surprising element -- namely that keeping the 7 point blot is not nearly
    as bad as most people would think it is. Besides being correct at DMP, we can apparently keep the
    7 point blot in the original at a cost of < 0.06. This seems very surprising to me. I would expect it to
    be something like a 0.3 blunder.

    Thoughts on why we can keep the 7 point blot (even though it might not be optimal)
    are welcome.

    Paul

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