• How to contain a checker 2

    From Timothy Chow@21:1/5 to All on Tue Oct 3 09:39:07 2023
    XGID=--aBCBB----AbB---b-bbbCbb-:1:1:1:31:0:0:0:0:10

    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 O |
    | X O | | O O O X O O |
    | | | X |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | O | | X X X X | | 2 |
    | O X | | X X X X O | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 143 O: 101 X-O: 0-0
    Cube: 2, X own cube
    X to play 31

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah...Clem@21:1/5 to Timothy Chow on Tue Oct 3 10:53:07 2023
    On 10/3/2023 9:39 AM, Timothy Chow wrote:
    XGID=--aBCBB----AbB---b-bbbCbb-:1:1:1:31:0:0:0:0:10

    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  O |
     | X           O    |   | O  O  O  X  O  O |  |                  |   |          X       |
     |                  |   |                  |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |                  |   |       X          | +---+
     | O                |   | X  X  X  X       | | 2 |  | O  X             |   | X  X  X  X  O    | +---+  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 143  O: 101 X-O: 0-0
    Cube: 2, X own cube
    X to play 31

    I'll make the ten point here. 11/10 4/1 leaves fewer shots, but this
    far back in the race I want to maintain contact. Making the ten means
    she has to break her midpoint to hit, while 11/7 allows her to escape
    with tempo.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Thu Oct 5 09:54:07 2023
    XGID=--aBCBB----AbB---b-bbbCbb-:1:1:1:31:0:0:0:0:10

    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 O |
    | X O | | O O O X O O |
    | | | X |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | O | | X X X X | | 2 |
    | O X | | X X X X O | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 143 O: 101 X-O: 0-0
    Cube: 2, X own cube
    X to play 31

    This is perhaps an even scarier version of the previous problem, since
    O has a five-point board, and getting hit is very painful. If X had a plausible safe play, then he would probably make it, but the only "safe"
    play here is 11/10 4/1, which still leaves 6 shots, and misplaces a
    blot on the 1pt. Making a bid for a five-prime with 11/7 is the best
    way to win. And the "safe" 11/10 4/1 still loses plenty of gammons.

    1. Rollout¹ 11/7 eq:-0.183
    Player: 39.78% (G:8.41% B:0.28%)
    Opponent: 60.22% (G:22.41% B:0.37%)
    Confidence: ±0.008 (-0.191..-0.174) - [100.0%]

    2. Rollout¹ 11/8 4/3 eq:-0.237 (-0.055)
    Player: 38.66% (G:7.95% B:0.26%)
    Opponent: 61.34% (G:24.59% B:0.45%)
    Confidence: ±0.008 (-0.245..-0.230) - [0.0%]

    3. Rollout¹ 11/10 4/1 eq:-0.285 (-0.102)
    Player: 35.93% (G:6.38% B:0.17%)
    Opponent: 64.07% (G:20.37% B:0.49%)
    Confidence: ±0.007 (-0.292..-0.278) - [0.0%]

    4. Rollout¹ 13/10 11/10 eq:-0.325 (-0.142)
    Player: 34.69% (G:5.87% B:0.21%)
    Opponent: 65.31% (G:21.18% B:0.44%)
    Confidence: ±0.007 (-0.332..-0.317) - [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=--aBCBB----AbB----bbCbbbb-:1:1:1:31:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O O O |
    | X O | | O X O O O O |
    | | | X |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X | +---+
    | O | | X X X X | | 2 |
    | O X | | X X X X O | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 137 O: 95 X-O: 0-0
    Cube: 2, X own cube
    X to play 31

    1. Rollout¹ 20/16 eq:-0.014
    Player: 46.01% (G:9.72% B:0.34%)
    Opponent: 53.99% (G:22.93% B:0.22%)
    Confidence: ±0.009 (-0.023..-0.005) - [91.6%]

    2. Rollout¹ 11/7 eq:-0.022 (-0.008)
    Player: 44.46% (G:9.34% B:0.31%)
    Opponent: 55.54% (G:18.90% B:0.10%)
    Confidence: ±0.008 (-0.030..-0.014) - [8.4%]

    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

    ---
    Tim Chow

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