• Rip two or fill in the gap?

    From Timothy Chow@21:1/5 to All on Sat Mar 5 07:30:05 2022
    XGID=-CDb-DD--------a--abbcbb--:1:-1:1:21:0:0:0:0:10

    X:Player 1 O:Player 2
    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 O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X X X |
    | | | X X X X |
    | | | X X O X X |
    | | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 55 O: 105 X-O: 0-0
    Cube: 2, O own cube
    X to play 21

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Mon Mar 7 08:43:59 2022
    XGID=-CDb-DD--------a--abbcbb--:1:-1:1:21:0:0:0:0:10

    X:Player 1 O:Player 2
    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 O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X X X |
    | | | X X X X |
    | | | X X O X X |
    | | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 55 O: 105 X-O: 0-0
    Cube: 2, O own cube
    X to play 21

    Most of us have been trained to recognize that a gap in the home board
    in front of the opponent's anchor is potentially very dangerous. So it
    may be tempting to "eliminate" that danger here by filling in the gap.
    But why are gaps dangerous? It's because they might force you to leave
    a blot. But how exactly is X going to be forced to leave a blot here?
    He has plenty of spares, and by the time he has to blot, O may have left
    to run off the gammon. If X had no 2's to play, then it might be a
    different story (see variant), but even then, ripping two has the
    benefit of increasing X's gammon wins.

    1. Rollout¹ 2/Off 1/Off eq:+0.835
    Player: 89.09% (G:9.53% B:0.08%)
    Opponent: 10.91% (G:0.00% B:0.00%)
    Confidence: ±0.004 (+0.831..+0.840) - [100.0%]

    2. Rollout¹ 6/5 2/Off eq:+0.797 (-0.038)
    Player: 88.24% (G:7.30% B:0.04%)
    Opponent: 11.76% (G:0.00% B:0.00%)
    Confidence: ±0.003 (+0.794..+0.801) - [0.0%]

    3. Rollout¹ 2/1 2/Off eq:+0.792 (-0.044)
    Player: 88.02% (G:7.52% B:0.04%)
    Opponent: 11.98% (G:0.00% B:0.00%)
    Confidence: ±0.004 (+0.788..+0.796) - [0.0%]

    4. Rollout¹ 6/4 5/4 eq:+0.756 (-0.080)
    Player: 87.24% (G:4.58% B:0.01%)
    Opponent: 12.76% (G:0.10% B:0.00%)
    Confidence: ±0.003 (+0.753..+0.758) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.207.pre-release

    -------
    Variant
    -------

    XGID=-CAb-DD--------a--abbcbb--:1:-1:1:21:0:0:0:0:10

    X:Player 1 O:Player 2
    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 O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X X |
    | | | X X X |
    | | | X X O X |
    | | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 49 O: 105 X-O: 0-0
    Cube: 2, O own cube
    X to play 21

    1. Rollout¹ 6/4 5/4 eq:+0.892
    Player: 90.79% (G:11.22% B:0.09%)
    Opponent: 9.21% (G:0.00% B:0.00%)
    Confidence: ±0.003 (+0.889..+0.895) - [100.0%]

    2. Rollout¹ 2/Off 1/Off eq:+0.878 (-0.015)
    Player: 87.31% (G:18.24% B:0.46%)
    Opponent: 12.69% (G:0.00% B:0.00%)
    Confidence: ±0.005 (+0.873..+0.883) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

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