• Time to break anchor? 2

    From Timothy Chow@21:1/5 to All on Thu Nov 16 08:47:56 2023
    XGID=-BACaBC-B-----c----bBbbcb-:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X |
    | X | | X X X X |
    | X | | X X O X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 97 O: 88 X-O: 0-0
    Cube: 1
    X to play 52

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah...Clem@21:1/5 to Timothy Chow on Fri Nov 17 10:36:00 2023
    On 11/16/2023 8:47 AM, Timothy Chow wrote:
    XGID=-BACaBC-B-----c----bBbbcb-:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game  +13-14-15-16-17-18------19-20-21-22-23-24-+
     |    O             |   | O  X  O  O  O  O |
     |    O             |   | O  X  O  O  O  O |
     |    O             |   |             O    |  |                  |   |                  |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |                  |   | X        X       |  |             X    |   | X  X     X     X |  |             X    |   | X  X  O  X  X  X |  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 97  O: 88 X-O: 0-0
    Cube: 1
    X to play 52



    Compared to the last problem in this series, X is now behind in the
    race, there's no blot in O's homeboard to shoot at, but there are blots
    for both in X's, and X can run a checker past O's outfield point.

    Which is to say we can't apply the lessons of the last problem here.

    I'll just clear the eight point again. This time, it covers the blot on
    the deuce which seems to be a significant improvement in X's position.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to ah...Clem on Fri Nov 17 22:41:36 2023
    On 11/17/2023 10:36 AM, ah...Clem wrote:
    On 11/16/2023 8:47 AM, Timothy Chow wrote:
    XGID=-BACaBC-B-----c----bBbbcb-:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     |    O             |   | O  X  O  O  O  O |
     |    O             |   | O  X  O  O  O  O |
     |    O             |   |             O    |
     |                  |   |                  |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |                  |   | X        X       |
     |             X    |   | X  X     X     X |
     |             X    |   | X  X  O  X  X  X |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 97  O: 88 X-O: 0-0
    Cube: 1
    X to play 52



    Compared to the last problem in this series, X is now behind in the
    race, there's no blot in O's homeboard to shoot at, but there are blots
    for both in X's, and X can run a checker past O's outfield point.

    Which is to say we can't apply the lessons of the last problem here.

    I'll just clear the eight point again. This time, it covers the blot on
    the deuce which seems to be a significant improvement in X's position.

    Clearing the 8pt does not cover the blot on the deuce.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Sat Nov 18 09:51:23 2023
    XGID=-BACaBC-B-----c----bBbbcb-:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X |
    | X | | X X X X |
    | X | | X X O X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 97 O: 88 X-O: 0-0
    Cube: 1
    X to play 52

    Playing 20/13 is a huge blunder in this position. O has no weaknesses
    in her board while X has a blot, and X is behind in the race.

    But there's another anchor-breaking play: 20/15 6/4*! This is the DMP
    play but it would seem to lose far too many gammons to be a viable
    candidate. Indeed, both XG 3-ply and XG 4-ply favor 6/1 3/1. Also,
    if X owns the cube already then the rollout favors 6/1 3/1. So 20/15
    6/4* is a "cube provocation play," which takes advantage of the highly inefficient cube which the opponent must immediately send over. If
    you think your opponent might not double from the bar, then 20/15 6/4*
    becomes even more attractive.

    Note that XG thinks that 8/6 8/3 is much worse than 6/1 3/1. Of course
    it's usually bad to kill all those checkers on the 1pt, but 8/6 8/3 is
    not going to win any beauty contests either. At minimum, it gives X
    options for how to play a 6, and it also blocks some otherwise good
    rolls for O (44 and 42 for example).

    1. Rollout¹ 20/15 6/4* eq:-0.454
    Player: 41.56% (G:7.47% B:0.06%)
    Opponent: 58.44% (G:33.09% B:2.01%)
    Confidence: ±0.014 (-0.469..-0.440) - [100.0%]

    2. Rollout¹ 6/1 3/1 eq:-0.475 (-0.021)
    Player: 35.99% (G:1.75% B:0.02%)
    Opponent: 64.01% (G:4.85% B:0.13%)
    Confidence: ±0.009 (-0.485..-0.466) - [0.0%]

    3. Rollout¹ 8/6 8/3 eq:-0.577 (-0.123)
    Player: 33.28% (G:2.19% B:0.04%)
    Opponent: 66.72% (G:5.20% B:0.12%)
    Confidence: ±0.008 (-0.585..-0.569) - [0.0%]

    4. Rollout¹ 20/13 eq:-0.695 (-0.240)
    Player: 33.76% (G:6.59% B:0.12%)
    Opponent: 66.24% (G:17.63% B:0.34%)
    Confidence: ±0.009 (-0.704..-0.686) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Rolled for both No double and Double
    Dice Seed: 271828
    First 3 moves: 3-ply, cube decisions: XG Roller+
    Remaining moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.211.pre-release

    -------------
    X owning cube
    -------------

    XGID=-BACaBC-B-----c----bBbbcb-:1:1:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O X O O O O |
    | O | | O X O O O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X | +---+
    | X | | X X X X | | 2 |
    | X | | X X O X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 97 O: 88 X-O: 0-0
    Cube: 2, X own cube
    X to play 52

    1. Rollout¹ 6/1 3/1 eq:-0.186
    Player: 35.92% (G:1.68% B:0.02%)
    Opponent: 64.08% (G:4.80% B:0.12%)
    Confidence: ±0.005 (-0.191..-0.180) - [100.0%]

    2. Rollout¹ 20/15 6/4* eq:-0.229 (-0.043)
    Player: 41.45% (G:7.51% B:0.07%)
    Opponent: 58.55% (G:33.09% B:1.88%)
    Confidence: ±0.007 (-0.236..-0.222) - [0.0%]

    3. Rollout¹ 8/6 8/3 eq:-0.256 (-0.071)
    Player: 33.19% (G:2.19% B:0.04%)
    Opponent: 66.81% (G:5.11% B:0.12%)
    Confidence: ±0.005 (-0.261..-0.251) - [0.0%]

    4. Rollout¹ 20/13 eq:-0.350 (-0.164)
    Player: 33.74% (G:5.99% B:0.11%)
    Opponent: 66.26% (G:17.32% B:0.34%)
    Confidence: ±0.005 (-0.354..-0.345) - [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)