• Stay back for a shot?

    From Timothy Chow@21:1/5 to All on Mon Oct 11 23:22:18 2021
    XGID=--BCBCC----A---------bAac-:1:1:1:22:0:0:0:0:10

    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 X O O |
    | | | O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X X | +---+
    | | | X X X X X | | 2 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 87 O: 13 X-O: 0-0
    Cube: 2, X own cube
    X to play 22

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Tue Oct 12 03:45:15 2021
    On Tuesday, October 12, 2021 at 4:22:18 AM UTC+1, Tim Chow wrote:
    XGID=--BCBCC----A---------bAac-:1:1:1:22:0:0:0:0:10

    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 X O O |
    | | | O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X X | +---+
    | | | X X X X X | | 2 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 87 O: 13 X-O: 0-0
    Cube: 2, X own cube
    X to play 22

    Stay back? Yes.
    But the reason isn't really "for a shot".
    Staying back often forces our opponent(s) to waste a roll
    by playing two checkers from the four point, instead of bearing two off. Furthermore, besides preserving winning chances, the stay-back plays don't sacrifice very many pips. If we play 11/5, then that is no more deep than we would
    expect so I don't think 11/5 wastes anything. And then if we cover the ace, we are also saving gammons in some variations. So staying back actually wastes less than two
    pips and potentially costs the opponent a whole roll.
    Covering the ace is important. A confident 11/5 3/1 for me.
    I wonder whether Tim will say that he ran because he saw the game winning chances as low,
    but neglected my point about wasting the opponent's next roll, and that he got dinged severely for it.

    Personally speaking, if I'm feeling a bit bad about something, then drinking Diet sodas makes me feel good
    and I don't think it makes me gain weight either. I know there's a theory that we gain weight through drinking
    Diet sodas because it makes you hungrier but I don't see that effect on me. I remain just as overweight as
    always, no matter how many Diet sodas I drink.

    And if you don't like Diet soda, then Ramsey theory is more entertaining.

    Paul

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  • From Timothy Chow@21:1/5 to All on Sun Oct 17 07:57:09 2021
    XGID=--BCBCC----A---------bAac-:1:1:1:22:0:0:0:0:10

    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 X O O |
    | | | O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X X | +---+
    | | | X X X X X | | 2 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 87 O: 13 X-O: 0-0
    Cube: 2, X own cube
    X to play 22

    I think that Paul's concept of making O waste half a roll if she
    rolls a 2 or a 3 is a good one. It's a little tricky to test this
    hypothesis with a variant but I have rolled out the position with
    an extra checker on O's 1pt; the equity difference between running
    and staying is smaller, perhaps due to the even/odd effect.

    1. Rollout¹ 11/5 3/1 eq:-1.457
    Player: 2.67% (G:0.00% B:0.00%)
    Opponent: 97.33% (G:51.47% B:0.74%)
    Confidence: ±0.002 (-1.459..-1.456) - [100.0%]

    2. Rollout¹ 11/5 6/4 eq:-1.490 (-0.033)
    Player: 2.55% (G:0.00% B:0.00%)
    Opponent: 97.45% (G:54.45% B:0.77%)
    Confidence: ±0.002 (-1.492..-1.488) - [0.0%]

    3. Rollout¹ 11/3 eq:-1.492 (-0.034)
    Player: 2.47% (G:0.00% B:0.00%)
    Opponent: 97.53% (G:54.46% B:0.78%)
    Confidence: ±0.002 (-1.494..-1.490) - [0.0%]

    4. Rollout¹ 11/5 4/2 eq:-1.510 (-0.052)
    Player: 2.71% (G:0.00% B:0.00%)
    Opponent: 97.29% (G:56.65% B:0.84%)
    Confidence: ±0.002 (-1.512..-1.507) - [0.0%]

    5. Rollout¹ 22/14 eq:-1.515 (-0.057)
    Player: 0.00% (G:0.00% B:0.00%)
    Opponent: 100.00% (G:51.47% B:0.00%)
    Confidence: ±0.000 (-1.515..-1.514) - [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

    -------
    Variant
    -------

    XGID=--BCBCC----A---------bAad-:1:1:1:22:0:0:0:0:10

    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 X O O |
    | | | O O |
    | | | O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X X | +---+
    | | | X X X X X | | 2 |
    | X | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 87 O: 14 X-O: 0-0
    Cube: 2, X own cube
    X to play 22

    1. Rollout¹ 11/5 3/1 eq:-1.247
    Player: 2.85% (G:0.00% B:0.00%)
    Opponent: 97.15% (G:31.45% B:0.12%)
    Confidence: ±0.001 (-1.248..-1.246) - [100.0%]

    2. Rollout¹ 22/14 eq:-1.260 (-0.014)
    Player: 0.00% (G:0.00% B:0.00%)
    Opponent: 100.00% (G:26.04% B:0.00%)
    Confidence: ±0.000 (-1.261..-1.260) - [0.0%]

    3. Rollout¹ 22/16 11/9 eq:-1.265 (-0.018)
    Player: 0.00% (G:0.00% B:0.00%)
    Opponent: 100.00% (G:26.51% B:0.00%)
    Confidence: ±0.000 (-1.265..-1.265) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves and cube decisions: XG Roller++
    Search interval: Gigantic

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

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  • From MK@21:1/5 to All on Mon Oct 18 00:55:08 2021
    Not sure. Maybe.

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