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  • The backgame isn't working out too well

    From Timothy Chow@21:1/5 to All on Mon Jun 20 09:24:32 2022
    XGID=-BBBB-BA---------bbcBBbcc-:2:1:1:51:0:0:0:0:10

    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 X X O O O |
    | O O | | O X X O O O |
    | | | O O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | | +---+
    | | | X X X X X | | 4 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 121 O: 63 X-O: 0-0
    Cube: 4, X own cube
    X to play 51

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From [email protected]@21:1/5 to Tim Chow on Tue Jun 21 08:00:18 2022
    On Monday, June 20, 2022 at 2:24:35 PM UTC+1, Tim Chow wrote:
    XGID=-BBBB-BA---------bbcBBbcc-:2:1:1:51:0:0:0:0:10

    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 X X O O O |
    | O O | | O X X O O O |
    | | | O O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | | +---+
    | | | X X X X X | | 4 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 121 O: 63 X-O: 0-0
    Cube: 4, X own cube
    X to play 51

    The backgame seems to be working out better than the attempts to prove that there are no odd perfect numbers.
    I don't think the 7 point checker has much value so we may as well burn it. Breaking an anchor needlessly gives the opponent chances to point or pick and pass.
    Note that we're unlikely to crunch so there's no reason not to break an anchor later.

    A confident 7/1.

    Paul

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Thu Jun 23 23:21:27 2022
    XGID=-BBBB-BA---------bbcBBbcc-:2:1:1:51:0:0:0:0:10

    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 X X O O O |
    | O O | | O X X O O O |
    | | | O O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | | +---+
    | | | X X X X X | | 4 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 121 O: 63 X-O: 0-0
    Cube: 4, X own cube
    X to play 51

    I was loath to kill a checker, but now is precisely the time when the
    backgame could finally pay off, if X keeps both anchors. Just as an
    example, suppose X knew ahead of time that O's next roll was going to
    be 53. X will then get a shot regardless, but he'll be in much better
    shape if he plays 7/1 than if he plays 20/15 7/6 and gets hit. Yes,
    if O rolls well and clears a point safely, then X will wish he had run
    off the 20pt, but X is a big underdog and needs to be thinking about
    how to take best advantage of the good sequences.

    1. Rollout¹ 7/1 eq:-0.632
    Player: 22.07% (G:1.10% B:0.02%)
    Opponent: 77.93% (G:17.37% B:0.04%)
    Confidence: ±0.005 (-0.637..-0.627) - [100.0%]

    2. Rollout¹ 20/15 7/6 eq:-0.697 (-0.065)
    Player: 21.37% (G:1.17% B:0.03%)
    Opponent: 78.63% (G:21.64% B:0.06%)
    Confidence: ±0.005 (-0.702..-0.691) - [0.0%]

    3. Rollout¹ 20/14 eq:-0.708 (-0.075)
    Player: 21.32% (G:1.15% B:0.03%)
    Opponent: 78.68% (G:22.35% B:0.08%)
    Confidence: ±0.005 (-0.713..-0.702) - [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

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