• Pottle or 4pt?

    From Timothy Chow@21:1/5 to All on Sun Aug 28 08:39:49 2022
    Here's an example where "Pottle" is an appropriate term since
    X has only one checker back.

    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
    | X O O O | | O O X |
    | X O O | | O O |
    | X | | O |
    | X | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X X | | X X |
    | O X X | | X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 141 O: 137 X-O: 0-0
    Cube: 1
    X to play 62

    ---
    Tim Chow

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  • From badgolferman@21:1/5 to Timothy Chow on Sun Aug 28 12:52:31 2022
    Timothy Chow wrote:

    Here's an example where "Pottle" is an appropriate term since
    X has only one checker back.

    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
    | X O O O | | O O X |
    | X O O | | O O |
    | X | | O |
    | X | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X X | | X X |
    | O X X | | X X O | +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 141 O: 137 X-O: 0-0
    Cube: 1
    X to play 62

    ---
    Tim Chow


    My back checker is not under attack so I will stay put and take the
    4-point.

    10/4, 6/4

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  • From pepstein5@gmail.com@21:1/5 to badgolferman on Sun Aug 28 11:52:47 2022
    On Sunday, August 28, 2022 at 1:52:33 PM UTC+1, badgolferman wrote:
    Timothy Chow wrote:

    Here's an example where "Pottle" is an appropriate term since
    X has only one checker back.

    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
    | X O O O | | O O X |
    | X O O | | O O |
    | X | | O |
    | X | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X X | | X X |
    | O X X | | X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 141 O: 137 X-O: 0-0
    Cube: 1
    X to play 62

    ---
    Tim Chow
    My back checker is not under attack so I will stay put and take the
    4-point.

    10/4, 6/4
    I'd make the 4 point for sure, too.
    The 4 point is one of the major goals in backgammon, and it's a clear asset in this position.
    However, Pottling to a place where we get hit with probability as high as 7/12 doesn't seem
    like anything special. Big blunder to Pottle in my (usually wrong) opinion.

    Paul

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  • From ah...Clem@21:1/5 to Timothy Chow on Mon Aug 29 09:40:51 2022
    On 8/28/2022 8:39 AM, Timothy Chow wrote:
    Here's an example where "Pottle" is an appropriate term since
    X has only one checker back.

    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
     | X     O     O  O |   | O  O           X |
     | X           O  O |   | O  O             |
     | X                |   | O                |  | X                |   | O                |  |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     | O              X |   | X                |  | O     X        X |   | X        X       |
     | O     X        X |   | X        X     O |  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 141  O: 137 X-O: 0-0
    Cube: 1
    X to play 62


    Making the four point is "very" constructive, so I'll do that.

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  • From ah...Clem@21:1/5 to Timothy Chow on Mon Aug 29 09:38:52 2022
    On 8/28/2022 8:39 AM, Timothy Chow wrote:
    Here's an example where "Pottle" is an appropriate term since
    X has only one checker back.

    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
     | X     O     O  O |   | O  O           X |
     | X           O  O |   | O  O             |
     | X                |   | O                |  | X                |   | O                |  |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     | O              X |   | X                |  | O     X        X |   | X        X       |
     | O     X        X |   | X        X     O |  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 141  O: 137 X-O: 0-0
    Cube: 1
    X to play 62

    13/7 is somewhat constructive, but not "very" constructive, so Pottle's
    law would say 24/16.

    But I'll opt for 13/7 24/22. The race is about even, O is less likely
    to hit on the 22, and except for the POH rolls gives better counterplay. Meanwhile, eleven in the zone vs a single checker seems strong.

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  • From Timothy Chow@21:1/5 to All on Tue Aug 30 08:08:09 2022
    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
    | X O O O | | O O X |
    | X O O | | O O |
    | X | | O |
    | X | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | O X | | X |
    | O X X | | X X |
    | O X X | | X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 141 O: 137 X-O: 0-0
    Cube: 1
    X to play 62

    In a recent post about Pottle's law, I wrote:

    If you're ahead or equal in the pip count, and your opponent has one
    or more checkers back, then you typically gain a lot by converting to
    a position in which you have no checkers back. This potential gain is usually worth exposing your last checker to a double shot, or
    sometimes even a triple shot.
    [...]
    What I often see are players who are afraid to run the last checker
    into a double shot, because they underestimate how much they gain if
    they are missed and they also underestimate the danger of having their
    last checker trapped and/or attacked.

    The present position is a good illustration of the above comments.
    There were three respondents, none of whom chose to Pottle. But XG
    says that it's a whopper not to Pottle.

    1. Rollout¹ 24/16 eq:-0.138
    Player: 47.54% (G:7.66% B:0.29%)
    Opponent: 52.46% (G:14.04% B:0.39%)
    Confidence: ±0.012 (-0.150..-0.127) - [100.0%]

    2. Rollout¹ 10/4 6/4 eq:-0.257 (-0.119)
    Player: 43.27% (G:11.65% B:0.39%)
    Opponent: 56.73% (G:15.64% B:0.57%)
    Confidence: ±0.013 (-0.271..-0.244) - [0.0%]

    3. Rollout¹ 24/22 13/7 eq:-0.270 (-0.131)
    Player: 44.30% (G:10.35% B:0.47%)
    Opponent: 55.70% (G:18.07% B:0.46%)
    Confidence: ±0.013 (-0.283..-0.256) - [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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  • From ah...Clem@21:1/5 to Timothy Chow on Tue Aug 30 13:55:26 2022
    On 8/30/2022 8:08 AM, Timothy Chow wrote:
    XGID=-a-B--CC--B-cD-a-bbdb---A-:0:0:1:62:0:0:0:0:10

    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-+
     | X     O     O  O |   | O  O           X |
     | X           O  O |   | O  O             |
     | X                |   | O                |  | X                |   | O                |  |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     | O              X |   | X                |  | O     X        X |   | X        X       |
     | O     X        X |   | X        X     O |  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 141  O: 137 X-O: 0-0
    Cube: 1
    X to play 62

        1. Rollout¹    24/16                        eq:-0.138
          Player:   47.54% (G:7.66% B:0.29%)
          Opponent: 52.46% (G:14.04% B:0.39%)
          Confidence: ±0.012 (-0.150..-0.127) - [100.0%]

        2. Rollout¹    10/4 6/4                     eq:-0.257 (-0.119)
          Player:   43.27% (G:11.65% B:0.39%)
          Opponent: 56.73% (G:15.64% B:0.57%)
          Confidence: ±0.013 (-0.271..-0.244) - [0.0%]

    This would seem to be an exception to Pottle's law, at least Stick's
    version of it. Few things are more constructive than making the four point.

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  • From Timothy Chow@21:1/5 to ah...Clem on Tue Aug 30 21:00:48 2022
    On 8/30/2022 1:55 PM, ah...Clem wrote:
    This would seem to be an exception to Pottle's law, at least Stick's
    version of it. Few things are more constructive than making the four point.

    There are never any exceptions to Stick's versions of backgammon
    heuristics.

    ---
    Tim Chow

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