• Some kind of cube action

    From Timothy Chow@21:1/5 to All on Sat Feb 12 12:21:30 2022
    For the purposes of my own records, I call this a containment cube,
    although I usually reserve that term for positions in which the
    doubler is behind in the pip count. Alternatively, you could call
    this a "blitz versus prime" cube, but X doesn't win as many gammons
    as in a typical blitz position, and a broken four-prime barely
    qualifies as a prime in my book.

    XGID=aBBB-DB------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | X |
    | | | X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 99 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action

    ---
    Tim Chow

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  • From Timothy Chow@21:1/5 to All on Tue Feb 15 08:53:48 2022
    XGID=aBBB-DB------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | X |
    | | | X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 99 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action

    I was astounded by how differently the given position and its variant
    below rolled out.

    Analyzed in Rollout
    No redouble
    Player Winning Chances: 72.01% (G:11.99% B:0.09%)
    Opponent Winning Chances: 27.99% (G:4.06% B:0.12%)
    Redouble/Take
    Player Winning Chances: 72.05% (G:12.13% B:0.09%)
    Opponent Winning Chances: 27.95% (G:4.63% B:0.14%)

    Cubeful Equities:
    No redouble: +0.723 (-0.110)
    Redouble/Take: +0.834
    Redouble/Pass: +1.000 (+0.166)

    Best Cube action: Redouble / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.007 (+0.717..+0.730)
    Confidence Double: ± 0.010 (+0.823..+0.844)

    eXtreme Gammon Version: 2.19.207.pre-release

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

    XGID=aBBB-CC------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | X X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 100 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action

    Analyzed in Rollout
    No redouble
    Player Winning Chances: 75.57% (G:15.51% B:0.13%)
    Opponent Winning Chances: 24.43% (G:3.86% B:0.13%)
    Redouble/Take
    Player Winning Chances: 75.61% (G:15.56% B:0.11%)
    Opponent Winning Chances: 24.39% (G:3.89% B:0.14%)

    Cubeful Equities:
    No redouble: +0.819 (-0.181)
    Redouble/Take: +1.072 (+0.072)
    Redouble/Pass: +1.000

    Best Cube action: Redouble / Pass

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.006 (+0.813..+0.824)
    Confidence Double: ± 0.011 (+1.061..+1.083)

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
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  • From Stick Rice@21:1/5 to Tim Chow on Tue Feb 15 22:42:39 2022
    On Tuesday, February 15, 2022 at 8:53:51 AM UTC-5, Tim Chow wrote:
    XGID=aBBB-DB------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | X |
    | | | X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 99 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action
    I was astounded by how differently the given position and its variant
    below rolled out.

    Analyzed in Rollout
    No redouble
    Player Winning Chances: 72.01% (G:11.99% B:0.09%)
    Opponent Winning Chances: 27.99% (G:4.06% B:0.12%)
    Redouble/Take
    Player Winning Chances: 72.05% (G:12.13% B:0.09%)
    Opponent Winning Chances: 27.95% (G:4.63% B:0.14%)

    Cubeful Equities:
    No redouble: +0.723 (-0.110)
    Redouble/Take: +0.834
    Redouble/Pass: +1.000 (+0.166)

    Best Cube action: Redouble / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.007 (+0.717..+0.730)
    Confidence Double: ± 0.010 (+0.823..+0.844)

    eXtreme Gammon Version: 2.19.207.pre-release

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

    XGID=aBBB-CC------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10
    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | X X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 100 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action
    Analyzed in Rollout
    No redouble
    Player Winning Chances: 75.57% (G:15.51% B:0.13%)
    Opponent Winning Chances: 24.43% (G:3.86% B:0.13%)
    Redouble/Take
    Player Winning Chances: 75.61% (G:15.56% B:0.11%)
    Opponent Winning Chances: 24.39% (G:3.89% B:0.14%)

    Cubeful Equities:
    No redouble: +0.819 (-0.181)
    Redouble/Take: +1.072 (+0.072)
    Redouble/Pass: +1.000

    Best Cube action: Redouble / Pass

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.006 (+0.813..+0.824)
    Confidence Double: ± 0.011 (+1.061..+1.083)

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

    Why? If you only take the numbers that make the full board immediately from the original to the variant you go from one [11] to three [21 11]. So you have two more rolls or ~2.78% on the first turn to have the nuts. That explains the bulk of the win %
    right there. You can add on top of that of course when the opponent enters with [42 41] or when they simply fan again and again you still have extra numbers to close your board that you wouldn't have had the other way.

    Stick

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  • From pepstein5@gmail.com@21:1/5 to Stick Rice on Wed Feb 16 02:17:01 2022
    On Wednesday, February 16, 2022 at 6:42:41 AM UTC, Stick Rice wrote:
    On Tuesday, February 15, 2022 at 8:53:51 AM UTC-5, Tim Chow wrote:
    XGID=aBBB-DB------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | X |
    | | | X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 99 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action
    I was astounded by how differently the given position and its variant below rolled out.

    Analyzed in Rollout
    No redouble
    Player Winning Chances: 72.01% (G:11.99% B:0.09%)
    Opponent Winning Chances: 27.99% (G:4.06% B:0.12%)
    Redouble/Take
    Player Winning Chances: 72.05% (G:12.13% B:0.09%)
    Opponent Winning Chances: 27.95% (G:4.63% B:0.14%)

    Cubeful Equities:
    No redouble: +0.723 (-0.110)
    Redouble/Take: +0.834
    Redouble/Pass: +1.000 (+0.166)

    Best Cube action: Redouble / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.007 (+0.717..+0.730)
    Confidence Double: ± 0.010 (+0.823..+0.844)

    eXtreme Gammon Version: 2.19.207.pre-release

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

    XGID=aBBB-CC------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10
    X:Player 2 O:Player 1
    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 |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | |
    | | | X X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 100 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action
    Analyzed in Rollout
    No redouble
    Player Winning Chances: 75.57% (G:15.51% B:0.13%)
    Opponent Winning Chances: 24.43% (G:3.86% B:0.13%)
    Redouble/Take
    Player Winning Chances: 75.61% (G:15.56% B:0.11%)
    Opponent Winning Chances: 24.39% (G:3.89% B:0.14%)

    Cubeful Equities:
    No redouble: +0.819 (-0.181)
    Redouble/Take: +1.072 (+0.072)
    Redouble/Pass: +1.000

    Best Cube action: Redouble / Pass

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.006 (+0.813..+0.824)
    Confidence Double: ± 0.011 (+1.061..+1.083)

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow
    Why? If you only take the numbers that make the full board immediately from the original to the variant you go from one [11] to three [21 11]. So you have two more rolls or ~2.78% on the first turn to have the nuts. That explains the bulk of the win %
    right there. You can add on top of that of course when the opponent enters with [42 41] or when they simply fan again and again you still have extra numbers to close your board that you wouldn't have had the other way.

    Good problem and variant, Tim, and good commentary by Stick.
    I think Tim's intuition behind his fainting with shock and wonder comes from the feeling that:
    "This inflexibility in our position makes us worse than the variant, but not much worse."
    However, this inflexibility is worse than usual because it's _permanent_ --- that's the important point.
    We can't legally move back from our 5 point to our 6 point.
    However, the intuition from our memory bank comes from remembering positions where (for example) an inflexibility
    like 4 on the six and 2 on the 5 wasn't hugely worse than 3 on the six and 3 on the 5. That inflexibility
    gets removed when we roll an ace, so it isn't so serious.
    This type of permanent inflexibility is much rarer than a removable inflexibility so it skews the intuition of non-experts.

    Paul

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  • From Timothy Chow@21:1/5 to Stick Rice on Wed Feb 16 08:21:47 2022
    On 2/16/2022 1:42 AM, Stick Rice wrote:
    Why? If you only take the numbers that make the full board immediately from the original to the variant you go from one [11] to three [21 11]. So you have two more rolls or ~2.78% on the first turn to have the nuts. That explains the bulk of the win
    % right there.

    I don't buy this explanation. In the original position, if X rolls 21,
    he doesn't lose immediately.

    ---
    Tim Chow

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  • From Timothy Chow@21:1/5 to Timothy Chow on Wed Feb 16 10:02:51 2022
    On 2/16/2022 8:21 AM, Timothy Chow wrote:
    On 2/16/2022 1:42 AM, Stick Rice wrote:
    Why?  If you only take the numbers that make the full board
    immediately from the original to the variant you go from one [11] to
    three [21 11].  So you have two more rolls or ~2.78% on the first turn
    to have the nuts.  That explains the bulk of the win % right there.

    I don't buy this explanation.  In the original position, if X rolls 21,
    he doesn't lose immediately.

    Maybe a better way to make my point is the variant position below.
    I don't believe that the swing on 21 is the primary explanation.

    XGID=aBBB-BD------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    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 X O O |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | X |
    | | | X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 101 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action

    Analyzed in XG Roller+
    Player Winning Chances: 74.14% (G:14.87% B:0.09%)
    Opponent Winning Chances: 25.86% (G:3.72% B:0.10%)

    Cubeless Equities: No Double=+0.594, Double=+1.199

    Cubeful Equities:
    No redouble: +0.801 (-0.199)
    Redouble/Take: +1.028 (+0.028)
    Redouble/Pass: +1.000

    Best Cube action: Redouble / Pass

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Wed Feb 16 08:48:36 2022
    On Wednesday, February 16, 2022 at 3:02:53 PM UTC, Tim Chow wrote:
    On 2/16/2022 8:21 AM, Timothy Chow wrote:
    On 2/16/2022 1:42 AM, Stick Rice wrote:
    Why? If you only take the numbers that make the full board
    immediately from the original to the variant you go from one [11] to
    three [21 11]. So you have two more rolls or ~2.78% on the first turn
    to have the nuts. That explains the bulk of the win % right there.

    I don't buy this explanation. In the original position, if X rolls 21,
    he doesn't lose immediately.
    Maybe a better way to make my point is the variant position below.
    I don't believe that the swing on 21 is the primary explanation.

    XGID=aBBB-BD------A--c-bccB-ab-:1:1:1:00:0:0:0:0:10

    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 X O O |
    | O O | | O O X O |
    | O | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | O | |
    | | | X |
    | | | X | +---+
    | | | X X X X X | | 2 |
    | | | X X X X X | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 101 O: 103 X-O: 0-0
    Cube: 2, X own cube
    X on roll, cube action
    Analyzed in XG Roller+
    Player Winning Chances: 74.14% (G:14.87% B:0.09%)
    Opponent Winning Chances: 25.86% (G:3.72% B:0.10%)

    Cubeless Equities: No Double=+0.594, Double=+1.199

    Cubeful Equities:
    No redouble: +0.801 (-0.199)
    Redouble/Take: +1.028 (+0.028)
    Redouble/Pass: +1.000

    Best Cube action: Redouble / Pass
    eXtreme Gammon Version: 2.19.207.pre-release

    But I explained this, didn't I??
    My analysis is totally consistent with this result.
    The point (that I've made before even while describing exactly this position) is that the new variant allows you to restore flexibility with your next ace.

    I also don't agree that you are rebutting Stick in any sensible way.
    If you change a position so that 21 switches from being a loser to a winner. Then the difference is 2/18 = 1/9 = 11%.
    That situation doesn't pertain here (as you say) and that is why Stick attributed
    the 21 swing to 2.78% rather than 11%.
    In your new variant, we don't make the point by 21 but we do have an extra pointmaker
    -- 22 and 11 instead of just 11.
    Further, as Stick and I said, the new variant allows us to roll an ace to prepare for 21 later.

    Paul

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  • From Timothy Chow@21:1/5 to peps...@gmail.com on Thu Feb 17 09:12:10 2022
    On 2/16/2022 11:48 AM, peps...@gmail.com wrote:
    But I explained this, didn't I??
    My analysis is totally consistent with this result.
    The point (that I've made before even while describing exactly this position) is that the new variant allows you to restore flexibility with your next ace.

    I also don't agree that you are rebutting Stick in any sensible way.
    If you change a position so that 21 switches from being a loser to a winner. Then the difference is 2/18 = 1/9 = 11%.
    That situation doesn't pertain here (as you say) and that is why Stick attributed
    the 21 swing to 2.78% rather than 11%.

    You're right that I initially missed that Stick said 2.78%.
    Nevertheless, note that the equity difference between my original
    position and my original variant is about 1.07 - 0.83 = 0.24.
    Now suppose we turn the cube and ask XG for the equity after X
    rolls 21 in each case. We get approximately 1.00 in the original
    position and 0.22 in the original variant, but we have to multiply
    these by 2 because XG divides by the cube value. So the swing is
    about 2.00 - 0.44 = 1.56, and dividing by 18 gives about .087, which
    does not account for the "bulk of" the equity difference.

    Stick did say the win % rather than the equity difference; I'm not
    sure what calculation he did, but in any case, my point is that the
    swing on an immediate 21 isn't the bulk of the explanation.

    In your new variant, we don't make the point by 21 but we do have an extra pointmaker
    -- 22 and 11 instead of just 11.
    Further, as Stick and I said, the new variant allows us to roll an ace to prepare for 21 later.

    Fair enough; I hadn't thought about how the new variant allows a
    good use of an ace. Nevertheless I am surprised by the size of
    the equity difference. I passed the cube, and if I had been told
    that my original variant was approximately a 1.07 pass, I would
    have guessed that my original position was at best a 0.95 take.
    If it *had* been a 0.95 take then I would have accepted that the
    huge immediate swing on 21 was the main point and left it at that.

    ---
    Tim Chow

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  • From Philippe Michel@21:1/5 to peps...@gmail.com on Sat Feb 19 19:51:22 2022
    On 2022-02-16, peps...@gmail.com <pepstein5@gmail.com> wrote:

    But I explained this, didn't I??
    My analysis is totally consistent with this result.
    The point (that I've made before even while describing exactly this position) is that the new variant allows you to restore flexibility with your next ace.

    One can add another variant and get a finer gradation. Looking at the
    pattern for points 5 to 7:

    420 Initial position: 1 joker, inflexible, unrepairable
    222 1 joker, inflexible, very repairable
    240 2 jokers, inflexible, repairable
    330 3 jokers, flexible

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  • From Timothy Chow@21:1/5 to All on Wed Jul 5 09:06:05 2023
    XGID=-BbBBBE--A--b----e-bb--bA-:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O X |
    | O | | O O O |
    | O | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 89 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action

    ---
    Tim Chow

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  • From Renan Moritz@21:1/5 to Timothy Chow on Wed Jul 5 07:57:27 2023
    On Wednesday, July 5, 2023 at 10:06:07 AM UTC-3, Timothy Chow wrote:
    XGID=-BbBBBE--A--b----e-bb--bA-:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O X |
    | O | | O O O |
    | O | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 89 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action

    ---
    Tim Chow


    This is a clear double, there are many roll exchanges that would make it into a pass next turn
    I am not sure about the take, the defender's position is too inflexible, it is going to be an uphill battle
    I guess I would pass, it will be too much work so save the game, but I would not be surprised if the machine takes

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From pepstein5@gmail.com@21:1/5 to Timothy Chow on Thu Jul 6 00:56:42 2023
    On Wednesday, July 5, 2023 at 2:06:07 PM UTC+1, Timothy Chow wrote:
    XGID=-BbBBBE--A--b----e-bb--bA-:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O X |
    | O | | O O O |
    | O | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 89 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action

    ---
    Tim Chow

    Disclaimer -- I am anti-Walting. I did read Renan's post which seemed very thoughtful. Without googling him, I'd guess he's a strong expert or even a world-class player.

    I think it's a double and a huge take. If we escape and then are missed,
    we have hugely lost our market. The combined parlay of escape/miss
    might well be less than O'Hagan's 25% but this threat repeats on every roll.
    So double now.

    The take is very clear, too. The opponent's 8 point stack is awkward but
    won't take long to improve. Crucially, our pip lead is far too small for a gammon. While not escaped, we are vulnerable to 44 and 55 as anti-jokers.
    Even if we lose our market by escaping, the opponent's deuce point backgame offers them residual equity. The opponent's made deuce point in their inner board is a weakness.
    They would rather move this two point to their four point (but this isn't legal).
    However, that's not enough of a weakness for a pass.

    D/T

    Paul

    --- SoupGate-Win32 v1.05
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  • From ah....Clem@21:1/5 to Timothy Chow on Thu Jul 6 12:47:36 2023
    On 7/5/2023 9:06 AM, Timothy Chow wrote:
    XGID=-BbBBBE--A--b----e-bb--bA-:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     |             O    |   | O  O        O  X |
     |             O    |   | O  O        O    |
     |             O    |   |                  |
     |             O    |   |                  |
     |             O    |   |                  |
     |                  |BAR|                  |
     |                  |   | X                |
     |                  |   | X                |
     |                  |   | X                |
     | O                |   | X  X  X  X  O  X |
     | O        X       |   | X  X  X  X  O  X |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 89  O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action



    Seems like O has to take this one. There are too many ways that this
    turns around.

    And it seems like if X can spring the runner to the outfield or even to
    the 21 or 22 and is not hit the market is lost. That's enough market
    losers to cube and even if X is hit he's still a clear favorite due to
    the race lead.

    Or to simplify, 2 of 3 PRAT.

    D/T.

    --
    Ah....Clem
    The future is fun, the future is fair.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Renan Moritz@21:1/5 to All on Thu Jul 6 12:41:27 2023
    Disclaimer -- I am anti-Walting. I did read Renan's post which seemed very thoughtful. Without googling him, I'd guess he's a strong expert or even a world-class player.

    Wow thanks so much. My best recent results were a couple of wins at the Montreal BG Club - I will show them this comment just for bragging

    The take is very clear, too. The opponent's 8 point stack is awkward but won't take long to improve. Crucially, our pip lead is far too small for a gammon. While not escaped, we are vulnerable to 44 and 55 as anti-jokers.
    Even if we lose our market by escaping, the opponent's deuce point backgame offers them residual equity. The opponent's made deuce point in their inner board is a weakness.
    They would rather move this two point to their four point (but this isn't legal). However, that's not enough of a weakness for a pass.

    Now *that* is thoughtful; I accept it's a take now

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From pepstein5@gmail.com@21:1/5 to Renan Moritz on Fri Jul 7 00:24:06 2023
    On Thursday, July 6, 2023 at 8:41:29 PM UTC+1, Renan Moritz wrote:
    Disclaimer -- I am anti-Walting. I did read Renan's post which seemed very thoughtful. Without googling him, I'd guess he's a strong expert or even a world-class player.
    Wow thanks so much. My best recent results were a couple of wins at the Montreal BG Club - I will show them this comment just for bragging
    The take is very clear, too. The opponent's 8 point stack is awkward but won't take long to improve. Crucially, our pip lead is far too small for a gammon. While not escaped, we are vulnerable to 44 and 55 as anti-jokers.
    Even if we lose our market by escaping, the opponent's deuce point backgame offers them residual equity. The opponent's made deuce point in their inner board is a weakness.
    They would rather move this two point to their four point (but this isn't legal). However, that's not enough of a weakness for a pass.

    Now *that* is thoughtful; I accept it's a take now

    Re my own strength, I don't play competitively.
    Based on XG's feedback, I'd estimate my PR at around 6.0 but I don't really know and haven't seriously measured it.

    Paul

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Fri Jul 7 08:22:36 2023
    XGID=-BbBBBE--A--b----e-bb--bA-:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O X |
    | O | | O O O |
    | O | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 89 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action

    This position requires carefully judging how good O's chances are
    of containing X's straggler. I didn't think that O's position was
    good enough to allow a take, because the 2pt is rather deep and the
    spares are all stacked on the 8pt. But XG says it's an easy take.
    But see also the variant, which illustrates that even moving X's
    straggler forward two pips makes a big difference.

    Analyzed in Rollout
    No double
    Player Winning Chances: 66.52% (G:20.58% B:0.65%)
    Opponent Winning Chances: 33.48% (G:3.14% B:0.08%)
    Double/Take
    Player Winning Chances: 66.47% (G:20.86% B:0.71%)
    Opponent Winning Chances: 33.53% (G:3.29% B:0.08%)

    Cubeful Equities:
    No double: +0.678 (-0.055)
    Double/Take: +0.733
    Double/Pass: +1.000 (+0.267)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.010 (+0.668..+0.688)
    Confidence Double: ± 0.015 (+0.719..+0.748)

    eXtreme Gammon Version: 2.19.211.pre-release

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

    XGID=-BbBBBE--A--b----e-bb-Ab--:0:0:1:00:0:0:0:0:10

    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 | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 87 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action

    Analyzed in Rollout
    No double
    Player Winning Chances: 70.40% (G:21.39% B:0.70%)
    Opponent Winning Chances: 29.60% (G:2.60% B:0.07%)
    Double/Take
    Player Winning Chances: 70.62% (G:21.25% B:0.72%)
    Opponent Winning Chances: 29.38% (G:2.64% B:0.08%)

    Cubeful Equities:
    No double: +0.771 (-0.198)
    Double/Take: +0.968
    Double/Pass: +1.000 (+0.032)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.011 (+0.760..+0.781)
    Confidence Double: ± 0.013 (+0.955..+0.982)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Renan Moritz@21:1/5 to All on Sat Jul 8 07:01:36 2023
    Also notice that X's strategy is very simple here: run away, as fast as you can "O" on the other hand has to play a containment game - hard game, with difficult hold-block-hit decisions ahead
    That turns position 2 into a pass for sure
    OTB I would be very biased towards passing this kind of position unless I were confident that I could contain X last checker
    Regards,

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stick Rice@21:1/5 to Timothy Chow on Tue Sep 19 12:19:34 2023
    On Friday, July 7, 2023 at 8:22:39 AM UTC-4, Timothy Chow wrote:
    XGID=-BbBBBE--A--b----e-bb--bA-:0:0:1:00:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | O | | O O O X |
    | O | | O O O |
    | O | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 89 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action
    This position requires carefully judging how good O's chances are
    of containing X's straggler. I didn't think that O's position was
    good enough to allow a take, because the 2pt is rather deep and the
    spares are all stacked on the 8pt. But XG says it's an easy take.
    But see also the variant, which illustrates that even moving X's
    straggler forward two pips makes a big difference.

    Analyzed in Rollout
    No double
    Player Winning Chances: 66.52% (G:20.58% B:0.65%)
    Opponent Winning Chances: 33.48% (G:3.14% B:0.08%)
    Double/Take
    Player Winning Chances: 66.47% (G:20.86% B:0.71%)
    Opponent Winning Chances: 33.53% (G:3.29% B:0.08%)

    Cubeful Equities:
    No double: +0.678 (-0.055)
    Double/Take: +0.733
    Double/Pass: +1.000 (+0.267)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.010 (+0.668..+0.688)
    Confidence Double: ± 0.015 (+0.719..+0.748)

    eXtreme Gammon Version: 2.19.211.pre-release

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

    XGID=-BbBBBE--A--b----e-bb-Ab--:0:0:1:00:0:0:0:0:10
    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 | | |
    | O | | |
    | O | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | O | | X X X X O X |
    | O X | | X X X X O X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 87 O: 138 X-O: 0-0
    Cube: 1
    X on roll, cube action
    Analyzed in Rollout
    No double
    Player Winning Chances: 70.40% (G:21.39% B:0.70%)
    Opponent Winning Chances: 29.60% (G:2.60% B:0.07%)
    Double/Take
    Player Winning Chances: 70.62% (G:21.25% B:0.72%)
    Opponent Winning Chances: 29.38% (G:2.64% B:0.08%)

    Cubeful Equities:
    No double: +0.771 (-0.198)
    Double/Take: +0.968
    Double/Pass: +1.000 (+0.032)

    Best Cube action: Double / Take

    Rollout:
    1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller
    Confidence No Double: ± 0.011 (+0.760..+0.781)
    Confidence Double: ± 0.013 (+0.955..+0.982)

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow

    Moving the straggler forward in these positions not only makes it wildly easier to escape, sometimes (such as here) it will disperse of potential horrible rolls/anti jokers for the person doubling. A decent swing on how [44 54] play in the original v.
    the variant for eg.

    Stick

    --- SoupGate-Win32 v1.05
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