• Holding game with extra checker back

    From Timothy Chow@21:1/5 to All on Thu Apr 13 08:12:11 2023
    XGID=--a-CbC-CB---D-aab-bbbb---: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 O |
    | X O | | O O O O |
    | X | | |
    | X | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X X |
    | X X | | X O X |
    | X X | | X O X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 124 O: 134 X-O: 0-0
    Cube: 1
    X to play 22

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Sat Apr 15 22:48:49 2023
    XGID=--a-CbC-CB---D-aab-bbbb---: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 O |
    | X O | | O O O O |
    | X | | |
    | X | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X X |
    | X X | | X O X |
    | X X | | X O X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 124 O: 134 X-O: 0-0
    Cube: 1
    X to play 22

    I hit here, but attacking isn't a priority for X in this position.
    He wants a safe and flexible position that will allow him to bring
    home all his checkers with a minimum of fuss. 8/2* 4/2 strips two
    points and reduces his flexibility.

    The PoH play is a much better candidate in the variant, where it
    unstacks X's awkward stack on the 6pt.

    1. Rollout¹ 13/11(2) 9/7(2) eq:+0.746
    Player: 71.82% (G:3.01% B:0.08%)
    Opponent: 28.18% (G:1.84% B:0.04%)
    Confidence: ±0.009 (+0.737..+0.755) - [100.0%]

    2. Rollout¹ 9/7(2) 8/4 eq:+0.680 (-0.066)
    Player: 69.69% (G:3.90% B:0.09%)
    Opponent: 30.31% (G:2.46% B:0.05%)
    Confidence: ±0.010 (+0.670..+0.689) - [0.0%]

    3. Rollout¹ 8/2* 4/2 eq:+0.671 (-0.075)
    Player: 69.13% (G:4.65% B:0.14%)
    Opponent: 30.87% (G:3.29% B:0.08%)
    Confidence: ±0.010 (+0.662..+0.681) - [0.0%]

    4. Rollout¹ 13/9(2) eq:+0.661 (-0.085)
    Player: 69.21% (G:3.18% B:0.11%)
    Opponent: 30.79% (G:2.23% B:0.04%)
    Confidence: ±0.009 (+0.653..+0.670) - [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=--a-BbE-BB---D-aab-bbbb---: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 O |
    | X O | | O O O O |
    | X | | |
    | X | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X O X |
    | X X | | X O X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 124 O: 134 X-O: 0-0
    Cube: 1
    X to play 22

    1. Rollout¹ 9/7(2) 6/4(2) eq:+0.679
    Player: 69.53% (G:3.97% B:0.10%)
    Opponent: 30.47% (G:2.63% B:0.06%)
    Confidence: ±0.010 (+0.669..+0.688) - [89.5%]

    2. Rollout¹ 6/2*(2) eq:+0.670 (-0.009)
    Player: 68.96% (G:4.65% B:0.12%)
    Opponent: 31.04% (G:3.24% B:0.07%)
    Confidence: ±0.009 (+0.661..+0.680) - [10.5%]

    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

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah...Clem@21:1/5 to Timothy Chow on Wed Oct 4 09:15:01 2023
    On 10/4/2023 9:04 AM, Timothy Chow wrote:
    XGID=---BBBBA----bC---cdd--BbA-:0:0:1:63:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game  +13-14-15-16-17-18------19-20-21-22-23-24-+
     | X           O  O |   | O        X  O  X |
     | X           O  O |   | O        X  O    |
     | X           O  O |   | O                |  |                O |   | O                |  |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |                  |   |                  |
     | O                |   | X  X  X  X       |
     | O              X |   | X  X  X  X       |  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 150  O: 106 X-O: 0-0
    Cube: 1
    X to play 63

    I'll keep the stinger in place since the race is so lopsided.

    22/13 is intriguing, but looks to lose too many gammons. OTOH, with X's
    strong board O might not risk hitting loose.

    QF implies he prosaic 13/4 is probably wrong, but that's what I'll do.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Wed Oct 4 09:04:29 2023
    XGID=---BBBBA----bC---cdd--BbA-:0:0:1:63:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O X O X |
    | X O O | | O X O |
    | X O O | | O |
    | O | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | O | | X X X X |
    | O X | | X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 150 O: 106 X-O: 0-0
    Cube: 1
    X to play 63

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Fri Oct 6 19:58:54 2023
    XGID=---BBBBA----bC---cdd--BbA-:0:0:1:63:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O X O X |
    | X O O | | O X O |
    | X O O | | O |
    | O | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | O | | X X X X |
    | O X | | X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 150 O: 106 X-O: 0-0
    Cube: 1
    X to play 63

    In a holding game with an extra checker back, deciding what to do with
    the extra checker can be tricky. Staying back can generate more contact
    and more opportunities for that much-needed shot. On the other hand,
    the extra checker can be vulnerable to attack, and it can interfere
    with your timing.

    In this position, XG favors stepping up with 24/21. I believe that a
    key motivation is to take advantage of O's bad rolls. In particular,
    63 and 53 are O's worst rolls, and 24/21 gives X a direct shot at O's
    blot after she plays 13/10. Of course, O has good rolls that point
    on X's head, but those rolls are excellent rolls for O anyway.

    The variant below makes a significant change to the position, but I
    think it's still instructive. 24/21 no longer makes O's bad rolls
    worse.

    1. Rollout¹ 24/21 13/7 eq:-0.577
    Player: 35.26% (G:5.33% B:0.18%)
    Opponent: 64.74% (G:7.66% B:0.11%)
    Confidence: ±0.010 (-0.587..-0.567) - [100.0%]

    2. Rollout¹ 13/10 13/7 eq:-0.651 (-0.074)
    Player: 33.82% (G:5.05% B:0.15%)
    Opponent: 66.18% (G:9.50% B:0.19%)
    Confidence: ±0.010 (-0.661..-0.641) - [0.0%]

    3. Rollout¹ 13/4 eq:-0.653 (-0.076)
    Player: 33.19% (G:5.11% B:0.15%)
    Opponent: 66.81% (G:8.78% B:0.17%)
    Confidence: ±0.011 (-0.663..-0.642) - [0.0%]

    4. Rollout¹ 24/15 eq:-0.674 (-0.097)
    Player: 32.41% (G:4.33% B:0.13%)
    Opponent: 67.59% (G:6.56% B:0.10%)
    Confidence: ±0.011 (-0.685..-0.663) - [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=---BBBBA----bC-b-cbd--BbA-:0:0:1:63:0:0:0:0:10

    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 O X |
    | X O O O | | O X O |
    | X O | | O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | O | | X X X X |
    | O X | | X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 150 O: 112 X-O: 0-0
    Cube: 1
    X to play 63

    1. Rollout¹ 13/4 eq:-0.758
    Player: 30.00% (G:4.98% B:0.12%)
    Opponent: 70.00% (G:9.28% B:0.22%)
    Confidence: ±0.010 (-0.768..-0.749) - [99.7%]

    2. Rollout¹ 24/21 13/7 eq:-0.778 (-0.020)
    Player: 29.78% (G:3.90% B:0.11%)
    Opponent: 70.22% (G:7.98% B:0.14%)
    Confidence: ±0.011 (-0.789..-0.768) - [0.3%]

    3. Rollout¹ 13/10 13/7 eq:-0.784 (-0.025)
    Player: 29.86% (G:4.26% B:0.11%)
    Opponent: 70.14% (G:9.79% B:0.23%)
    Confidence: ±0.010 (-0.794..-0.773) - [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

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)