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  • What's an indirect shot between friends?

    From Timothy Chow@21:1/5 to All on Sat Feb 25 09:42:27 2023
    XGID=aBbCB-BAC-B---b--bcb-c----:1:-1:1:43:0:0:0:0:10

    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 | | 2 |
    | O | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X |
    | X X | | X X X O X |
    | X X X | | X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 154 X-O: 0-0
    Cube: 2, O own cube
    X to play 43

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Timothy Chow on Sat Feb 25 12:43:07 2023
    On Saturday, February 25, 2023 at 9:42:29 AM UTC-5, Timothy Chow wrote:
    XGID=aBbCB-BAC-B---b--bcb-c----:1:-1:1:43:0:0:0:0:10

    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 | | 2 |
    | O | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X |
    | X X | | X X X O X |
    | X X X | | X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 154 X-O: 0-0
    Cube: 2, O own cube
    X to play 43

    ---
    Tim Chow

    10/6 7/4 looks good despite the hit from O with 55. It avoid making the 7 point which will subsequently have to come down, leaves spares on every point above the anchor for making the 5 point if necessary or for pointing on the anchor when broken. 7
    rolls make the 5 point immediately if we're not hit. If we're hit with the 55, our board is still strong for dealing with the anchor.

    10/6 10/7 makes the 7 point. That 7 point will have to come down, probably behind an open 5 point - uncomfortable. It leaves 3 rolls to make the 5 point later. Only 2 spares to hit the anchor with.

    8/4 7/3 is a wreck. No flexibility.

    10/6 7/4

    Bob

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Mon Feb 27 08:33:56 2023
    XGID=aBbCB-BAC-B---b--bcb-c----:1:-1:1:43:0:0:0:0:10

    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 | | 2 |
    | O | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X |
    | X X | | X X X O X |
    | X X X | | X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 82 O: 154 X-O: 0-0
    Cube: 2, O own cube
    X to play 43

    A heuristic that I've found useful is that when we're bearing in
    and the opponent has an anchor and a checker on the bar, then it's
    okay to leave 1 or 2 shots (out of 36) if doing so facilitates our
    subsequent bearin. Moves that volunteer more than 2 shots can be
    okay too, but have to be considered carefully.

    When the opponent is anchored on our 2pt, then checkers on our bar
    point are awkward; sixes force us to dump 7/1. So we're generally
    looking to bear in checkers from our bar point (except with a 6),
    not stack more checkers on it. These considerations point to 7/4.
    Then 10/6 is the natural 4, given that we're not worried about
    giving O a 55 joker from the bar.

    It's interesting to consider the variant, in which XG says that
    stacking up on the bar point isn't so bad. Part of what's going
    on in the variant is that checkers on the 11pt are also not so
    easy to bear in safely, given that our 5pt is still open.

    1. Rollout¹ 10/6 7/4 eq:+0.719
    Player: 73.76% (G:35.23% B:1.18%)
    Opponent: 26.24% (G:1.50% B:0.06%)
    Confidence: ±0.007 (+0.713..+0.726) - [100.0%]

    2. Rollout¹ 8/4 7/4 eq:+0.678 (-0.042)
    Player: 71.96% (G:36.16% B:1.23%)
    Opponent: 28.04% (G:2.13% B:0.06%)
    Confidence: ±0.008 (+0.669..+0.686) - [0.0%]

    3. Rollout¹ 10/7 10/6 eq:+0.614 (-0.106)
    Player: 71.17% (G:31.56% B:0.86%)
    Opponent: 28.83% (G:2.42% B:0.10%)
    Confidence: ±0.007 (+0.606..+0.621) - [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=aBbCB-BAC--B--b--bcb-c----:1:-1:1:45:0:0:0:0:10

    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 | | 2 |
    | O | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | X | | X |
    | X X | | X X X O X |
    | X X X | | X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 84 O: 154 X-O: 0-0
    Cube: 2, O own cube
    X to play 45

    1. Rollout¹ 11/6 7/3 eq:+0.624
    Player: 71.18% (G:33.04% B:1.08%)
    Opponent: 28.82% (G:2.47% B:0.10%)
    Confidence: ±0.008 (+0.616..+0.632) - [75.2%]

    2. Rollout¹ 11/6 8/4 eq:+0.620 (-0.004)
    Player: 70.29% (G:35.69% B:1.30%)
    Opponent: 29.71% (G:2.81% B:0.10%)
    Confidence: ±0.007 (+0.613..+0.628) - [24.2%]

    3. Rollout¹ 11/7 11/6 eq:+0.612 (-0.012)
    Player: 71.02% (G:31.84% B:0.94%)
    Opponent: 28.98% (G:2.60% B:0.10%)
    Confidence: ±0.008 (+0.604..+0.620) - [0.6%]

    4. Rollout¹ 8/3 7/3 eq:+0.572 (-0.052)
    Player: 69.15% (G:33.79% B:1.04%)
    Opponent: 30.85% (G:3.26% B:0.13%)
    Confidence: ±0.009 (+0.564..+0.581) - [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

    ---
    Tim Chow

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