• Split?

    From Timothy Chow@21:1/5 to All on Sat Jun 10 08:36:48 2023
    XGID=----B-E-D-b-cB---c-e--b-B-:0:0:1:43:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O X |
    | X O | | O O X |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | O X | | X |
    | O O X | | X X |
    | O O X | | X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 144 O: 129 X-O: 0-0
    Cube: 1
    X to play 43

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah....Clem@21:1/5 to Timothy Chow on Sun Jun 11 11:38:49 2023
    On 6/10/2023 8:36 AM, Timothy Chow wrote:
    XGID=----B-E-D-b-cB---c-e--b-B-:0:0:1:43:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     | X           O    |   | O        O     X |
     | X           O    |   | O        O     X |
     |             O    |   | O                |
     |                  |   | O                |
     |                  |   | O                |
     |                  |BAR|                  |
     |                  |   | X                |
     |             X    |   | X                |
     | O           X    |   | X                |
     | O     O     X    |   | X     X          |
     | O     O     X    |   | X     X          |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 144  O: 129 X-O: 0-0
    Cube: 1
    X to play 43


    I don't enjoy sitting on the ace point waiting patiently to lose, so
    I'll split here. It might be an error, but the longer you wait to split
    the more difficult the decision becomes, so splitting early even when
    it's not correct can forestall a much bigger error later.

    Above advice from Paul Money, who seems to have disappeared from the
    backgammon scene.

    So, I'll split here and slot the five point. seems better than the
    reverse split that puts a spare on the four instead of slotting the
    point we want to make. Slotting both five points can't be all bad, right?

    --
    Ah....Clem
    The future is fun, the future is fair.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Mon Jun 12 08:47:07 2023
    XGID=----B-E-D-b-cB---c-e--b-B-:0:0:1:43:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O X |
    | X O | | O O X |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | O X | | X |
    | O O X | | X X |
    | O O X | | X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 144 O: 129 X-O: 0-0
    Cube: 1
    X to play 43

    When the opponent has played an early 55 (played 13/3(2)) then we
    are usually disincentivized to split, because the opponent wants
    to attack or race, and splitting plays into those game plans.
    Instead, we want to contain the opponent's rear checkers.

    But if those rear checkers have escaped, the calculus changes.
    We may need to split in order to bid for an advanced anchor, or
    provoke contact. The risk of getting attacked is still present,
    of course, so we have to balance that risk.

    1. Rollout¹ 24/20 8/5 eq:-0.485
    Player: 37.84% (G:10.49% B:0.43%)
    Opponent: 62.16% (G:17.98% B:0.67%)
    Confidence: ±0.011 (-0.495..-0.474) - [100.0%]

    2. Rollout¹ 24/20 6/3 eq:-0.523 (-0.039)
    Player: 36.96% (G:9.71% B:0.38%)
    Opponent: 63.04% (G:18.39% B:0.61%)
    Confidence: ±0.011 (-0.535..-0.512) - [0.0%]

    3. Rollout¹ 24/21 24/20 eq:-0.528 (-0.044)
    Player: 35.98% (G:6.42% B:0.22%)
    Opponent: 64.02% (G:14.33% B:0.37%)
    Confidence: ±0.010 (-0.538..-0.518) - [0.0%]

    4. Rollout¹ 24/21 8/4 eq:-0.547 (-0.062)
    Player: 36.24% (G:9.49% B:0.38%)
    Opponent: 63.76% (G:17.73% B:0.61%)
    Confidence: ±0.011 (-0.557..-0.536) - [0.0%]

    5. Rollout¹ 8/5 8/4 eq:-0.565 (-0.080)
    Player: 34.85% (G:8.48% B:0.26%)
    Opponent: 65.15% (G:12.80% B:0.54%)
    Confidence: ±0.012 (-0.577..-0.553) - [0.0%]

    6. Rollout¹ 8/5 6/2 eq:-0.567 (-0.082)
    Player: 35.21% (G:8.75% B:0.28%)
    Opponent: 64.79% (G:13.58% B:0.67%)
    Confidence: ±0.012 (-0.579..-0.554) - [0.0%]

    7. Rollout¹ 24/21 6/2 eq:-0.570 (-0.086)
    Player: 35.94% (G:9.20% B:0.33%)
    Opponent: 64.06% (G:18.47% B:0.71%)
    Confidence: ±0.011 (-0.582..-0.559) - [0.0%]

    8. Rollout¹ 8/4 6/3 eq:-0.598 (-0.114)
    Player: 34.64% (G:8.06% B:0.25%)
    Opponent: 65.36% (G:13.51% B:0.57%)
    Confidence: ±0.011 (-0.610..-0.587) - [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 1
    ---------

    XGID=----B-EbD---cB---c-e--b-B-:0:0:1:43:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O X |
    | X O | | O O X |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | O X | | X |
    | O X O | | X X |
    | O X O | | X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 144 O: 135 X-O: 0-0
    Cube: 1
    X to play 43

    1. Rollout¹ 24/20 8/5 eq:-0.296
    Player: 43.06% (G:11.63% B:0.46%)
    Opponent: 56.94% (G:17.85% B:0.58%)
    Confidence: ±0.013 (-0.309..-0.283) - [97.6%]

    2. Rollout¹ 8/5 6/2 eq:-0.313 (-0.017)
    Player: 41.72% (G:12.69% B:0.39%)
    Opponent: 58.28% (G:15.37% B:0.76%)
    Confidence: ±0.011 (-0.324..-0.302) - [2.4%]

    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 2
    ---------

    XGID=----B-E-D---cBb--c-e--b-B-:0:0:1:43:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O O | | O O X |
    | X O O | | O O X |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | O X | | X |
    | O X | | X X |
    | O X | | X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 144 O: 121 X-O: 0-0
    Cube: 1
    X to play 43

    1. Rollout¹ 8/5 6/2 eq:-0.813
    Player: 28.65% (G:5.23% B:0.17%)
    Opponent: 71.35% (G:11.79% B:0.55%)
    Confidence: ±0.013 (-0.827..-0.800) - [100.0%]

    [ ... various non-splitting plays omitted ...]

    2. Rollout¹ 24/21 8/4 eq:-0.892 (-0.078)
    Player: 28.98% (G:5.32% B:0.17%)
    Opponent: 71.02% (G:16.94% B:0.49%)
    Confidence: ±0.012 (-0.904..-0.879) - [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)