• Mutual Holding Game

    From Robert Zimmerman@21:1/5 to All on Fri Apr 28 10:10:14 2023
    XGID=-B-BAbC-C---B--b-c-cBbb-a-:0:0:1:54:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +24-23-22-21-20-19------18-17-16-15-14-13-+
    | O O O X O | | O O |
    | O O X O | | O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X O X | | X X |
    | X X X O X | | X X |
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+
    Pip count X: 118 O: 117 X-O: 0-0
    Cube: 1
    X to play 54

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to Robert Zimmerman on Sat Apr 29 11:56:23 2023
    On 4/28/2023 1:10 PM, Robert Zimmerman wrote:
    XGID=-B-BAbC-C---B--b-c-cBbb-a-:0:0:1:54:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +24-23-22-21-20-19------18-17-16-15-14-13-+
    | O O O X O | | O O |
    | O O X O | | O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X O X | | X X |
    | X X X O X | | X X |
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+
    Pip count X: 118 O: 117 X-O: 0-0
    Cube: 1
    X to play 54

    In a mutual holding game with equal pip count, one generally tries not
    to leave any shots. Despite the blot in O's board, I think that
    principle holds here. The default move is 8/4 6/1, and the only problem
    is that it kills a checker and leaves us totally stripped. But what
    else is there? I don't see that leaving a direct shot is any better.
    That leaves 12/3, but that creates an awkward structure and still leaves
    6 indirect shots. I'd just play 8/4 6/1. Even if our next roll is not
    that great, we can probably still play off the 12pt and maintain a
    decent position.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Robert Zimmerman on Mon May 1 18:40:09 2023
    On Friday, April 28, 2023 at 1:10:16 PM UTC-4, Robert Zimmerman wrote:
    XGID=-B-BAbC-C---B--b-c-cBbb-a-:0:0:1:54:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +24-23-22-21-20-19------18-17-16-15-14-13-+
    | O O O X O | | O O |
    | O O X O | | O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X O X | | X X |
    | X X X O X | | X X |
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+
    Pip count X: 118 O: 117 X-O: 0-0
    Cube: 1
    X to play 54
    XG wants to leave a blot on the bar point. I'm still a little surprised that it is worth it. Before I started reading modern backgammon material, especially Michy, I might have made that play, but now....? Haven't come up with any illuminating variants,
    but I'm guessing a lead in the race might change XG's appetite for leaving the blot.
    Bob

    XGID=-B-BAbC-C---B--b-c-cBbb-a-:0:0:1:54:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O | | O X O O O |
    | O O | | O X O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X O X X |
    | X X | | X O X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 118 O: 117 X-O: 0-0
    Cube: 1
    X to play 54

    1. Rollout¹ 12/7 8/4 eq:-0.106
    Player: 46.94% (G:8.09% B:0.22%)
    Opponent: 53.06% (G:7.05% B:0.20%)
    Confidence: ±0.015 (-0.121..-0.091) - [100.0%]

    2. Rollout¹ 8/4 6/1 eq:-0.161 (-0.055)
    Player: 45.34% (G:6.02% B:0.14%)
    Opponent: 54.66% (G:7.37% B:0.22%)
    Confidence: ±0.015 (-0.176..-0.147) - [0.0%]

    3. Rollout¹ 12/3 eq:-0.165 (-0.059)
    Player: 45.05% (G:6.91% B:0.20%)
    Opponent: 54.95% (G:6.75% B:0.23%)
    Confidence: ±0.014 (-0.179..-0.151) - [0.0%]

    4. Rollout² 8/4 8/3 eq:-0.183 (-0.077)
    Player: 44.67% (G:7.53% B:0.16%)
    Opponent: 55.33% (G:7.42% B:0.24%)
    Confidence: ±0.014 (-0.198..-0.169) - [0.0%]

    5. Rollout³ 8/3 6/2 eq:-0.191 (-0.085)
    Player: 44.93% (G:6.05% B:0.10%)
    Opponent: 55.07% (G:7.85% B:0.25%)
    Confidence: ±0.016 (-0.207..-0.175) - [0.0%]

    eXtreme Gammon Version: 2.10

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to Robert Zimmerman on Tue May 2 08:52:00 2023
    On 5/1/2023 9:40 PM, Robert Zimmerman wrote:
    XG wants to leave a blot on the bar point. I'm still a little surprised that it is worth it. Before I started reading modern backgammon material, especially Michy, I might have made that play, but now....? Haven't come up with any illuminating variants,
    but I'm guessing a lead in the race might change XG's appetite for leaving the blot.

    The blot in O's board has something to do with it. I mentioned
    this in my commentary, but didn't think it was enough to justify
    the bold play. Evidently XG begs to differ.

    XGID=-B-BAbC-C---B--b-c-cBbc---:0:0:1:54:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O | | O X O O |
    | O O | | O X O O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X O X X |
    | X X | | X O X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 118 O: 119 X-O: 0-0
    Cube: 1
    X to play 54

    1. XG Roller++ 8/4 6/1 eq:-0.129
    Player: 46.22% (G:5.77% B:0.10%)
    Opponent: 53.78% (G:6.81% B:0.18%)

    2. XG Roller++ 8/3 6/2 eq:-0.132 (-0.003)
    Player: 45.99% (G:6.22% B:0.10%)
    Opponent: 54.01% (G:7.18% B:0.21%)

    3. XG Roller++ 12/3 eq:-0.156 (-0.028)
    Player: 45.33% (G:5.57% B:0.09%)
    Opponent: 54.67% (G:5.91% B:0.17%)

    4. XG Roller++ 12/7 8/4 eq:-0.187 (-0.059)
    Player: 44.28% (G:8.08% B:0.15%)
    Opponent: 55.72% (G:7.29% B:0.23%)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Timothy Chow on Tue May 2 09:01:25 2023
    On Tuesday, May 2, 2023 at 8:52:03 AM UTC-4, Timothy Chow wrote:
    On 5/1/2023 9:40 PM, Robert Zimmerman wrote:
    XG wants to leave a blot on the bar point. I'm still a little surprised that it is worth it. Before I started reading modern backgammon material, especially Michy, I might have made that play, but now....? Haven't come up with any illuminating
    variants, but I'm guessing a lead in the race might change XG's appetite for leaving the blot.
    The blot in O's board has something to do with it. I mentioned
    this in my commentary, but didn't think it was enough to justify
    the bold play. Evidently XG begs to differ.

    XGID=-B-BAbC-C---B--b-c-cBbc---:0:0:1:54:0:0:0:0:10
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O O | | O X O O |
    | O O | | O X O O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | X X | | X O X X |
    | X X | | X O X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 118 O: 119 X-O: 0-0
    Cube: 1
    X to play 54
    1. XG Roller++ 8/4 6/1 eq:-0.129
    Player: 46.22% (G:5.77% B:0.10%)
    Opponent: 53.78% (G:6.81% B:0.18%)

    2. XG Roller++ 8/3 6/2 eq:-0.132 (-0.003)
    Player: 45.99% (G:6.22% B:0.10%)
    Opponent: 54.01% (G:7.18% B:0.21%)

    3. XG Roller++ 12/3 eq:-0.156 (-0.028)
    Player: 45.33% (G:5.57% B:0.09%)
    Opponent: 54.67% (G:5.91% B:0.17%)

    4. XG Roller++ 12/7 8/4 eq:-0.187 (-0.059)
    Player: 44.28% (G:8.08% B:0.15%)
    Opponent: 55.72% (G:7.29% B:0.23%)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow
    Seems right. You can put that checker just about anywhere else and the safer play prevails.
    Bob

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From MK@21:1/5 to Robert Zimmerman on Fri May 5 03:17:08 2023
    On April 28, 2023 at 11:10:16 AM UTC-6, Robert Zimmerman wrote:

    XGID=-B-BAbC-C---B--b-c-cBbb-a-:0:0:1:54:0:0:0:0:10
    X to play 54

    12/4, 8/7

    MK

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