• Bearing in against an ace-point game

    From Timothy Chow@21:1/5 to All on Fri Jun 2 09:56:52 2023
    XGID=-bBB-CDBB-----a-bbabb--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 O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X |
    | | | X X |
    | X X | | X X X X O |
    | X X | | X X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 79 O: 128 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 ah....Clem@21:1/5 to Timothy Chow on Sat Jun 3 14:06:42 2023
    On 6/2/2023 9:56 AM, Timothy Chow wrote:
    XGID=-bBB-CDBB-----a-bbabb--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  O        O    | | 2 |
     |                  |   |             O    | +---+
     |                  |   |                  |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   | X                |
     |                  |   | X  X             |
     |             X  X |   | X  X     X  X  O |
     |             X  X |   | X  X     X  X  O |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 79  O: 128 X-O: 0-0
    Cube: 2, O own cube
    X to play 43

    I can't imagine leaving a direct shot is right.

    That leaves playing two off the six, one off each of the 5 and 6, or
    leaving an indirect with 8/5 6/2.

    The latter looks more flexible and if we're hit (1 in 18) there's plenty
    of counterplay. So I'll do that.

    --
    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 Sun Jun 4 09:32:45 2023
    XGID=-bBB-CDBB-----a-bbabb--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 O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X |
    | | | X X |
    | X X | | X X X X O |
    | X X | | X X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 79 O: 128 X-O: 0-0
    Cube: 2, O own cube
    X to play 43

    Like ah_clem, I didn't think that leaving a direct shot was the right
    idea here. But XG does. O is playing a phantom 1-4 backgame, and
    8/4 7/4 eliminates the phantom. This may be regarded as a type of
    pay now or pay later problem. You might even think of it as a "Bagai" position, after Jeremy Bagai, who posted some problems to BGOnline
    on a similar theme, back in the day.

    http://alum.mit.edu/www/tchow/cg/www.bgonline.org/forums/97723.html

    Of course, if O's offensive position is sufficiently strong, then
    playing safe would be indicated; see the variant.

    1. Rollout¹ 8/4 7/4 eq:+0.675
    Player: 77.98% (G:21.23% B:1.00%)
    Opponent: 22.02% (G:1.61% B:0.03%)
    Confidence: ±0.006 (+0.670..+0.681) - [100.0%]

    2. Rollout¹ 8/5 6/2 eq:+0.611 (-0.064)
    Player: 77.24% (G:14.94% B:0.62%)
    Opponent: 22.76% (G:0.91% B:0.03%)
    Confidence: ±0.006 (+0.606..+0.617) - [0.0%]

    3. Rollout¹ 8/5 8/4 eq:+0.608 (-0.067)
    Player: 75.87% (G:20.10% B:0.84%)
    Opponent: 24.13% (G:2.34% B:0.08%)
    Confidence: ±0.006 (+0.602..+0.614) - [0.0%]

    4. Rollout¹ 7/4 7/3 eq:+0.591 (-0.084)
    Player: 75.31% (G:20.06% B:0.87%)
    Opponent: 24.69% (G:2.09% B:0.08%)
    Confidence: ±0.006 (+0.585..+0.597) - [0.0%]

    5. Rollout¹ 6/3 6/2 eq:+0.589 (-0.086)
    Player: 77.20% (G:13.10% B:0.48%)
    Opponent: 22.80% (G:1.01% B:0.03%)
    Confidence: ±0.005 (+0.584..+0.594) - [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=-bBB-CDBB-------bbbbb--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 O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X |
    | | | X X |
    | X X | | X X X X O |
    | X X | | X X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 79 O: 124 X-O: 0-0
    Cube: 2, O own cube
    X to play 43

    1. Rollout¹ 6/3 6/2 eq:+0.592
    Player: 77.98% (G:10.81% B:0.36%)
    Opponent: 22.02% (G:0.87% B:0.03%)
    Confidence: ±0.004 (+0.588..+0.596) - [70.8%]

    2. Rollout¹ 8/5 6/2 eq:+0.590 (-0.002)
    Player: 77.44% (G:12.44% B:0.45%)
    Opponent: 22.56% (G:0.97% B:0.03%)
    Confidence: ±0.005 (+0.586..+0.595) - [29.2%]

    3. Rollout¹ 8/4 7/4 eq:+0.565 (-0.027)
    Player: 75.86% (G:15.71% B:0.51%)
    Opponent: 24.14% (G:1.83% B:0.06%)
    Confidence: ±0.006 (+0.560..+0.571) - [0.0%]

    ¹ 905 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow

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