• 5-3 "backgame" 21 to play

    From ah....Clem@21:1/5 to All on Thu Jul 6 22:56:03 2023
    This came up in match play, but I don't think the score mattered so
    recasting it as unlimited without Jacoby.

    Pure play? Mobility? Hybrid? Something else?


    XGID=-a---BC-C---bB---cbdBcB-A-:0:0:1:21:0:0:0:0:10

    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 X O X X |
    | X O O | | O X O X |
    | O | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | O X | | X X |
    | O X | | X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 186 O: 124 X-O: 0-0
    Cube: 1
    X to play 21

    --
    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 Jul 7 08:10:56 2023
    On 7/6/2023 10:56 PM, ah....Clem wrote:

    This came up in match play, but I don't think the score mattered so
    recasting it as unlimited without Jacoby.

    Pure play? Mobility? Hybrid? Something else?


    XGID=-a---BC-C---bB---cbdBcB-A-:0:0:1:21:0:0:0:0:10

    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  X  O  X     X |
     | X           O  O |   | O  X  O  X       |
     |             O    |   | O     O          |
     |                  |   | O                |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |             X    |   | X                |
     | O           X    |   | X  X             |
     | O           X    |   | X  X           O |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 186  O: 124 X-O: 0-0
    Cube: 1
    X to play 21

    I'd try the pure priming play of 8/7 6/4. An alternative idea would
    be to step up with 24/22, in order to be able to escape a back checker
    with a 6, but I don't think we need to do that yet. That straggler is
    giving us shot possibilities and is not in immediate danger of being
    attacked. If we're hit, we could make a third anchor, which would be
    helpful.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah....Clem@21:1/5 to All on Sat Jul 8 14:36:21 2023
    62 pips of timing is marginal for a viable backgame, but the principles
    of mobility and pure play still hold for positions like this.

    I was more concerned about mobility, so I played 24/22 and then the
    chicken play of 6/5. A better play would involve both mobility and pure
    play, i.e. slotting either the 7 or the 4 after 24/22, with the four
    being clearly better. Interestingly, a play that accomplishes neither,
    8/5, comes out better in the rollout than my play.

    The bot massively favors the pure pure play, which is to slot both the 7
    and the four.

    I'm at a loss to provide a variant here. XGID=-a---BC-C---bB---cbdBcB-A-:0:0:1:21:0:0:0:0:10

    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 X O X X |
    | X O O | | O X O X |
    | O | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | O X | | X X |
    | O X | | X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 186 O: 124 X-O: 0-0
    Cube: 1
    X to play 21

    1. Rollout¹ 8/7 6/4 eq:-0.253
    Player: 48.50% (G:9.69% B:0.39%)
    Opponent: 51.50% (G:26.94% B:1.09%)
    Confidence: ±0.020 (-0.273..-0.233) - [100.0%]
    Duration: 10 minutes 38 seconds

    2. Rollout¹ 24/23 6/4 eq:-0.333 (-0.081)
    Player: 45.85% (G:8.82% B:0.36%)
    Opponent: 54.15% (G:24.81% B:0.81%)
    Confidence: ±0.017 (-0.351..-0.316) - [0.0%]
    Duration: 10 minutes 12 seconds

    3. Rollout¹ 8/5 eq:-0.375 (-0.122)
    Player: 43.75% (G:8.71% B:0.36%)
    Opponent: 56.25% (G:22.21% B:0.70%)
    Confidence: ±0.016 (-0.391..-0.359) - [0.0%]
    Duration: 9 minutes 17 seconds

    4. Rollout¹ 24/22 6/5 eq:-0.397 (-0.145)
    Player: 42.82% (G:8.01% B:0.33%)
    Opponent: 57.18% (G:21.28% B:0.46%)
    Confidence: ±0.017 (-0.414..-0.381) - [0.0%]
    Duration: 10 minutes 17 seconds

    5. Rollout¹ 24/22 8/7 eq:-0.403 (-0.151)
    Player: 44.43% (G:8.20% B:0.34%)
    Opponent: 55.57% (G:25.62% B:0.60%)
    Confidence: ±0.015 (-0.419..-0.388) - [0.0%]
    Duration: 9 minutes 57 seconds


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


    eXtreme Gammon Version: 2.10

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stick Rice@21:1/5 to Timothy Chow on Tue Sep 19 12:23:54 2023
    On Friday, July 7, 2023 at 8:10:59 AM UTC-4, Timothy Chow wrote:
    On 7/6/2023 10:56 PM, ah....Clem wrote:

    This came up in match play, but I don't think the score mattered so recasting it as unlimited without Jacoby.

    Pure play? Mobility? Hybrid? Something else?


    XGID=-a---BC-C---bB---cbdBcB-A-:0:0:1:21:0:0:0:0:10

    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 X O X X |
    | X O O | | O X O X |
    | O | | O O |
    | | | O |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | X |
    | O X | | X X |
    | O X | | X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 186 O: 124 X-O: 0-0
    Cube: 1
    X to play 21
    I'd try the pure priming play of 8/7 6/4. An alternative idea would
    be to step up with 24/22, in order to be able to escape a back checker
    with a 6, but I don't think we need to do that yet. That straggler is
    giving us shot possibilities and is not in immediate danger of being attacked. If we're hit, we could make a third anchor, which would be helpful.

    ---
    Tim Chow

    We don't leave the checker on the 24pt there because it's giving us shot possibilities. We leave it there because stepping up to the 22pt still doesn't do a great job of allowing us to escape. If we had rolled a four for example that's not [42 22]
    obviously, we step up to the 20pt without hesitation.

    Stick

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