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  • 5pt problem 2

    From Timothy Chow@21:1/5 to All on Thu Oct 27 08:38:15 2022
    XGID=--aBa-DBB---bD-b---eb-b-A-:0:0:1:31:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O O X |
    | X O | | O O O |
    | X | | O |
    | X | | O |
    | | | O |
    | |BAR| |
    | | | |
    | | | X |
    | | | X |
    | O X X | | X X |
    | O X X | | X O X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 136 O: 136 X-O: 0-0
    Cube: 1
    X to play 31

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah...Clem@21:1/5 to Timothy Chow on Thu Oct 27 11:17:15 2022
    On 10/27/2022 8:38 AM, Timothy Chow wrote:
    XGID=--aBa-DBB---bD-b---eb-b-A-:0:0:1:31:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game  +13-14-15-16-17-18------19-20-21-22-23-24-+
     | X     O          |   | O  O     O     X |
     | X     O          |   | O  O     O       |
     | X                |   | O                |  | X                |   | O                |  |                  |   | O                |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   | X                |
     |                  |   | X                |
     | O           X  X |   | X        X       |
     | O           X  X |   | X     O  X  O    |  +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 136  O: 136 X-O: 0-0
    Cube: 1
    X to play 31


    Making the five point exposes a double shot while O has a strong board. Magriel's safe v bold criteria all point to a safe play.

    I'll try 24/23 to see more daylight and then 6/3 to unstack and minimize
    shots.

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to ah...Clem on Sat Oct 29 08:11:24 2022
    On 10/27/2022 11:17 AM, ah...Clem wrote:
    On 10/27/2022 8:38 AM, Timothy Chow wrote:
    XGID=--aBa-DBB---bD-b---eb-b-A-:0:0:1:31:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     | X     O          |   | O  O     O     X |
     | X     O          |   | O  O     O       |
     | X                |   | O                |
     | X                |   | O                |
     |                  |   | O                |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   | X                |
     |                  |   | X                |
     | O           X  X |   | X        X       |
     | O           X  X |   | X     O  X  O    |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 136  O: 136 X-O: 0-0
    Cube: 1
    X to play 31


    Making the five point exposes a double shot while O has a strong board. Magriel's safe v bold criteria all point to a safe play.

    I would say that most of Magriel's criteria either don't apply or are inconclusive here---neither player has an anchor, and after X makes the
    5pt, the boards are equally strong. The one clear criterion is that
    O has more checkers back.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Sat Oct 29 08:09:26 2022
    XGID=--aBa-DBB---bD-b---eb-b-A-:0:0:1:31:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O O X |
    | X O | | O O O |
    | X | | O |
    | X | | O |
    | | | O |
    | |BAR| |
    | | | |
    | | | X |
    | | | X |
    | O X X | | X X |
    | O X X | | X O X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 136 O: 136 X-O: 0-0
    Cube: 1
    X to play 31

    Making the 5pt is often worth it even if it leaves a double direct shot,
    but in this position, XG balks. The 8pt is also valuable in this
    position, and X has a much safer play (24/23 6/3) whose only real
    disadvantage is that it creates a dilly builder.

    1. Rollout¹ 24/23 6/3 eq:-0.210
    Player: 46.37% (G:10.34% B:0.44%)
    Opponent: 53.63% (G:19.42% B:0.45%)
    Confidence: ±0.013 (-0.223..-0.197) - [100.0%]

    2. Rollout¹ 8/5 6/5 eq:-0.285 (-0.075)
    Player: 44.68% (G:13.12% B:0.62%)
    Opponent: 55.32% (G:22.76% B:0.79%)
    Confidence: ±0.012 (-0.296..-0.273) - [0.0%]

    3. Rollout¹ 6/2* eq:-0.291 (-0.081)
    Player: 44.40% (G:12.04% B:0.49%)
    Opponent: 55.60% (G:21.83% B:0.70%)
    Confidence: ±0.014 (-0.304..-0.277) - [0.0%]

    4. Rollout¹ 7/4* 4/3 eq:-0.305 (-0.095)
    Player: 43.50% (G:13.03% B:0.51%)
    Opponent: 56.50% (G:22.03% B:0.77%)
    Confidence: ±0.012 (-0.317..-0.293) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.211.pre-release

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)