• Must X lift the blot?

    From Timothy Chow@21:1/5 to All on Wed Apr 19 08:27:14 2023
    XGID=--bC-AEbD----B----abcbc---:0:0:1:22:0:0:0:0:10

    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 O |
    | X | | O O O O |
    | | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X X |
    | X O | | X X O |
    | X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 133 X-O: 0-0
    Cube: 1
    X to play 22

    ---
    Tim Chow

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Timothy Chow on Wed Apr 19 06:49:02 2023
    On Wednesday, April 19, 2023 at 8:27:17 AM UTC-4, Timothy Chow wrote:
    XGID=--bC-AEbD----B----abcbc---:0:0:1:22:0:0:0:0:10

    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 O |
    | X | | O O O O |
    | | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X X |
    | X O | | X X O |
    | X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 133 X-O: 0-0
    Cube: 1
    X to play 22

    ---
    Tim Chow
    I've seen some pretty ugly positions that are the right play when you've moved your back checkers out. But the plays I'm finding after lifting the checker are not only ugly, but have nasty 6s and uncomfortable 5s, e.g. 8/4 6/4 5/5, 6/4(2) 5/1, and others.
    Too much for me to do with my eyes open. I'd play 13/11(2) and 6/4(2) with now a candidate to cover (or return hit) the 5 coming from the 11 point.
    Still, a sneaking suspicion I'm wrong. I'm falling into every trap lately.
    Bob

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Fri Apr 21 09:53:14 2023
    XGID=--bC-AEbD----B----abcbc---:0:0:1:22:0:0:0:0:10

    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 O |
    | X | | O O O O |
    | | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X X |
    | X O | | X X O |
    | X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 133 X-O: 0-0
    Cube: 1
    X to play 22

    It's pretty clear what the pros and cons of lifting the blot are, and
    it's mainly a question of how much weight to put on the various factors.
    XG clearly favors leaving the 5pt slotted. But see also the variant.

    1. Rollout¹ 13/11(2) 6/4(2) eq:+0.616
    Player: 67.87% (G:11.23% B:0.48%)
    Opponent: 32.13% (G:6.05% B:0.13%)
    Confidence: ±0.008 (+0.608..+0.624) - [100.0%]

    2. Rollout¹ 6/4(2) 5/1 eq:+0.551 (-0.065)
    Player: 64.66% (G:11.16% B:0.38%)
    Opponent: 35.34% (G:6.37% B:0.15%)
    Confidence: ±0.010 (+0.541..+0.561) - [0.0%]

    3. Rollout¹ 13/11(2) 5/1 eq:+0.543 (-0.073)
    Player: 63.93% (G:7.50% B:0.23%)
    Opponent: 36.07% (G:5.21% B:0.12%)
    Confidence: ±0.010 (+0.533..+0.553) - [0.0%]

    4. Rollout¹ 8/4 6/4 5/3 eq:+0.521 (-0.095)
    Player: 63.78% (G:10.79% B:0.33%)
    Opponent: 36.22% (G:5.89% B:0.13%)
    Confidence: ±0.012 (+0.509..+0.533) - [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=--bC-AEbD----B----bbbbb-a-:0:0:1:22:0:0:0:0:10

    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 O O |
    | X O | | O O O O |
    | | | |
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X X |
    | X O | | X X O |
    | X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 102 O: 133 X-O: 0-0
    Cube: 1
    X to play 22

    1. Rollout¹ 13/11(2) 6/4(2) eq:+0.588
    Player: 67.40% (G:11.08% B:0.41%)
    Opponent: 32.60% (G:5.86% B:0.13%)
    Confidence: ±0.005 (+0.583..+0.593) - [98.6%]

    2. Rollout¹ 6/4(2) 5/1 eq:+0.577 (-0.011)
    Player: 65.24% (G:11.57% B:0.37%)
    Opponent: 34.76% (G:6.24% B:0.15%)
    Confidence: ±0.009 (+0.568..+0.586) - [1.4%]

    ¹ 2592 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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