• This one's obvious, right?

    From ah....Clem@21:1/5 to All on Wed Aug 17 10:38:02 2022
    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O X X |
    | O | | O X O O X X |
    | O | | O O |
    | O | | O |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | | | X X X |
    | X X | | X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 195 O: 81 X-O: 0-0
    Cube: 1
    X to play 31





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

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  • From pepstein5@gmail.com@21:1/5 to ah....Clem on Wed Aug 17 14:39:51 2022
    On Wednesday, August 17, 2022 at 3:38:00 PM UTC+1, ah....Clem wrote:
    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O X X |
    | O | | O X O O X X |
    | O | | O O |
    | O | | O |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | | | X X X |
    | X X | | X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 195 O: 81 X-O: 0-0
    Cube: 1
    X to play 31

    I'm playing 11/7. No, it is not in the least obvious that this maximises our equity.
    It would be absolutely unsurprising if we do better by keeping a checker on the 8 point,
    to hope to build our board.
    But I'll take the 4 prime with 11/7 anyway.

    I would like to say in advance that I will be slightly irritated (but only slightly) if it turns
    out that we can improve on the natural 11/7 by 0.000000000000000000000001 points,
    and that this is what we're supposed to marvel at in amazement.
    To astonish us (me anyway), I'd like to see that 11/7 is wildly wrong, like a transposition
    where you put sugar on your chips (or fries) and ketchup in your coffee.

    Paul

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  • From Timothy Chow@21:1/5 to ah....Clem on Wed Aug 17 21:40:31 2022
    On 8/17/2022 10:38 AM, ah....Clem wrote:

    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1   O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     | X              O |   | O  X  O  O  X  X |
     |                O |   | O  X  O  O  X  X |
     |                O |   | O        O       |
     |                O |   | O                |
     |                  |   | 6                |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |                  |   |                  |
     |                  |   | X  X  X          |
     |    X           X |   | X  X  X          |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 195  O: 81 X-O: 0-0
    Cube: 1
    X to play 31

    I think I'd give O 5's and 6's with 24/20. Even if it doesn't
    go well at first and I get pointed on, her 4 checkers on her
    bar point mean that her 6's are going to have to be played 7/1,
    which gives me chances of getting and hitting another shot
    later on.

    ---
    Tim Chow

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  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Thu Aug 18 01:17:26 2022
    On Thursday, August 18, 2022 at 2:40:36 AM UTC+1, Tim Chow wrote:
    On 8/17/2022 10:38 AM, ah....Clem wrote:

    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O X X |
    | O | | O X O O X X |
    | O | | O O |
    | O | | O |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | | | X X X |
    | X X | | X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 195 O: 81 X-O: 0-0
    Cube: 1
    X to play 31
    I think I'd give O 5's and 6's with 24/20. Even if it doesn't
    go well at first and I get pointed on, her 4 checkers on her
    bar point mean that her 6's are going to have to be played 7/1,
    which gives me chances of getting and hitting another shot
    later on.

    ---
    Tim Chow
    Oh yes, that's clever!
    I missed that tactic.

    And this is indeed an important point, with a lot of equity at stake.
    I think that if we (almost certainly wrongly) maintain our opponent's inner board points
    (as I assumed was "obvious"), then there isn't much equity involved in how we play the other checkers.

    Paul

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  • From Stick Rice@21:1/5 to peps...@gmail.com on Thu Aug 18 02:30:07 2022
    On Thursday, August 18, 2022 at 4:17:28 AM UTC-4, peps...@gmail.com wrote:
    On Thursday, August 18, 2022 at 2:40:36 AM UTC+1, Tim Chow wrote:
    On 8/17/2022 10:38 AM, ah....Clem wrote:

    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O X X |
    | O | | O X O O X X |
    | O | | O O |
    | O | | O |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | | | X X X |
    | X X | | X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 195 O: 81 X-O: 0-0
    Cube: 1
    X to play 31
    I think I'd give O 5's and 6's with 24/20. Even if it doesn't
    go well at first and I get pointed on, her 4 checkers on her
    bar point mean that her 6's are going to have to be played 7/1,
    which gives me chances of getting and hitting another shot
    later on.

    ---
    Tim Chow
    Oh yes, that's clever!
    I missed that tactic.

    And this is indeed an important point, with a lot of equity at stake.
    I think that if we (almost certainly wrongly) maintain our opponent's inner board points
    (as I assumed was "obvious"), then there isn't much equity involved in how we play the other checkers.

    Paul

    It's a good thing you missed it. You don't abandon the back anchor in a well timed backgame to maybe get a shot that you aren't likely to hit and even if you do aren't ready to contain.

    The obvious play should be 7/3, not 11/7. I'd take 12, 8 as an acceptable play too. We aren't likely to get + hit a shot for at least several turns so we stick our checkers where they're supposed to go. Making the bar point now wraps up pips when we
    still want to use them due to timing to make the 3pt.

    Stick

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  • From Timothy Chow@21:1/5 to Stick Rice on Thu Aug 18 08:14:34 2022
    On 8/18/2022 5:30 AM, Stick Rice wrote:
    It's a good thing you missed it. You don't abandon the back anchor in a well timed backgame to maybe get a shot that you aren't likely to hit and even if you do aren't ready to contain.

    Yeah, I succumbed to the temptation to look for a QF play.
    Hopefully I wouldn't play 24/20 in a real game.

    ---
    Tim Chow

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  • From ah....Clem@21:1/5 to All on Thu Aug 18 10:59:59 2022
    Making the solid four prime seemed obvious to me and I didn't really
    consider other plays. XGR++ likes slotting the three point with my play
    being a small but significant (.028) error.

    Full rollout tells a slightly different story; after 10368 trials
    slotting the three is still on top but it's still within the margin of
    error (much to Paul's annoyance).

    11/7 is only a .010 error and the curious 13/9 is second at .006.

    I didn't roll out tearing up the anchors, but the best one according to
    XGR++ is a whopper.

    Bottom line is that slotting the next point we want to make (pure play)
    is the right idea and the slot trumps making a solid prime, presumably
    because O won't be leaving a shot right away.

    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O X X |
    | O | | O X O O X X |
    | O | | O O |
    | O | | O |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | | | X X X |
    | X X | | X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 195 O: 81 X-O: 0-0
    Cube: 1
    X to play 31

    1. Rollout¹ 7/3 eq:-0.250
    Player: 51.45% (G:3.29% B:0.12%)
    Opponent: 48.55% (G:25.54% B:5.36%)
    Confidence: ±0.008 (-0.258..-0.242) - [81.6%]
    Duration: 45 minutes 05 seconds

    2. Rollout¹ 13/9 eq:-0.256 (-0.006)
    Player: 51.30% (G:3.22% B:0.13%)
    Opponent: 48.70% (G:25.63% B:5.37%)
    Confidence: ±0.008 (-0.264..-0.248) - [14.2%]
    Duration: 42 minutes 35 seconds

    3. Rollout¹ 11/7 eq:-0.260 (-0.010)
    Player: 51.27% (G:3.21% B:0.12%)
    Opponent: 48.73% (G:25.65% B:5.42%)
    Confidence: ±0.008 (-0.268..-0.252) - [2.5%]
    Duration: 42 minutes 08 seconds

    4. Rollout¹ 13/12 11/8 eq:-0.261 (-0.011)
    Player: 51.20% (G:3.19% B:0.12%)
    Opponent: 48.80% (G:25.67% B:5.44%)
    Confidence: ±0.008 (-0.269..-0.253) - [1.7%]
    Duration: 37 minutes 58 seconds

    5. XG Roller++ 20/17 11/10 eq:-0.374 (-0.124)
    Player: 49.48% (G:2.63% B:0.09%)
    Opponent: 50.52% (G:27.05% B:6.45%)


    ¹ 10368 Games rolled with Variance Reduction.
    Moves: 3-ply, cube decisions: XG Roller


    eXtreme Gammon Version: 2.10



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

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From pepstein5@gmail.com@21:1/5 to Stick Rice on Thu Aug 18 10:40:31 2022
    On Thursday, August 18, 2022 at 10:30:09 AM UTC+1, Stick Rice wrote:
    On Thursday, August 18, 2022 at 4:17:28 AM UTC-4, peps...@gmail.com wrote:
    On Thursday, August 18, 2022 at 2:40:36 AM UTC+1, Tim Chow wrote:
    On 8/17/2022 10:38 AM, ah....Clem wrote:

    XGID=----BBBA---A-A----dfBbcBB-:0:0:1:31:0:0:3:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X O O X X |
    | O | | O X O O X X |
    | O | | O O |
    | O | | O |
    | | | 6 |
    | |BAR| |
    | | | |
    | | | |
    | | | |
    | | | X X X |
    | X X | | X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 195 O: 81 X-O: 0-0
    Cube: 1
    X to play 31
    I think I'd give O 5's and 6's with 24/20. Even if it doesn't
    go well at first and I get pointed on, her 4 checkers on her
    bar point mean that her 6's are going to have to be played 7/1,
    which gives me chances of getting and hitting another shot
    later on.

    ---
    Tim Chow
    Oh yes, that's clever!
    I missed that tactic.

    And this is indeed an important point, with a lot of equity at stake.
    I think that if we (almost certainly wrongly) maintain our opponent's inner board points
    (as I assumed was "obvious"), then there isn't much equity involved in how we play the other checkers.

    Paul
    It's a good thing you missed it. You don't abandon the back anchor in a well timed backgame to maybe get a shot that you aren't likely to hit and even if you do aren't ready to contain.

    The obvious play should be 7/3, not 11/7. I'd take 12, 8 as an acceptable play too. We aren't likely to get + hit a shot for at least several turns so we stick our checkers where they're supposed to go. Making the bar point now wraps up pips when we
    still want to use them due to timing to make the 3pt.

    Stick

    Normally, I would assume that the equity differences between 7/3, 11/7 and 12,8 are small. If they're not, then I've really learned something.

    Paul

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  • From ah....Clem@21:1/5 to peps...@gmail.com on Thu Aug 18 17:42:38 2022
    On 8/18/2022 1:40 PM, peps...@gmail.com wrote:


    Normally, I would assume that the equity differences between 7/3, 11/7 and 12,8 are small.

    They are. As is the case with 13/9 as well.




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

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to ah....Clem on Fri Aug 19 08:22:55 2022
    On 8/18/2022 10:59 AM, ah....Clem wrote:
    11/7 is only a .010 error and the curious 13/9 is second at .006.

    I would not have played 13/9, but it's not that curious if you
    conceive of X's strategic goal as making the 3pt.

    ---
    Tim Chow

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