• Make a second anchor?

    From Timothy Chow@21:1/5 to All on Mon Sep 25 08:49:19 2023
    XGID=-----aE-Ba--dD---d-e-BA--A:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X X |
    | X O | | O X |
    | X O | | O |
    | X O | | O |
    | | X | O |
    | |BAR| |
    | | | X |
    | O | | X |
    | O | | X |
    | O X | | X |
    | O O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 187 O: 150 X-O: 0-0
    Cube: 1
    X to play 52

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah....Clem@21:1/5 to Timothy Chow on Mon Sep 25 12:06:26 2023
    On 9/25/2023 8:49 AM, Timothy Chow wrote:
    XGID=-----aE-Ba--dD---d-e-BA--A:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     | X           O    |   | O     X  X       |
     | X           O    |   | O     X          |
     | X           O    |   | O                |
     | X           O    |   | O                |
     |                  | X | O                |
     |                  |BAR|                  |
     |                  |   | X                |
     | O                |   | X                |
     | O                |   | X                |
     | O           X    |   | X                |
     | O        O  X    |   | X  O             |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 187  O: 150 X-O: 0-0
    Cube: 1
    X to play 52

    Not enough timing for a backgame, and 54 backgames are not exactly the
    best. Meanwhile, O has a bunch of stacked points plus two blots and no
    board. I'll play bar/23 13/8 to unstack, put a spare on the 8, spread
    checkers around to catch a blot (O is stacked so probably won't be able
    to clean up the blots), and hang back to maintain contact.

    Making a second anchor doesn't look bad though.

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

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stick Rice@21:1/5 to ah....Clem on Wed Sep 27 07:56:04 2023
    On Monday, September 25, 2023 at 12:06:29 PM UTC-4, ah....Clem wrote:
    On 9/25/2023 8:49 AM, Timothy Chow wrote:
    XGID=-----aE-Ba--dD---d-e-BA--A:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X X |
    | X O | | O X |
    | X O | | O |
    | X O | | O |
    | | X | O |
    | |BAR| |
    | | | X |
    | O | | X |
    | O | | X |
    | O X | | X |
    | O O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 187 O: 150 X-O: 0-0
    Cube: 1
    X to play 52
    Not enough timing for a backgame, and 54 backgames are not exactly the
    best. Meanwhile, O has a bunch of stacked points plus two blots and no board. I'll play bar/23 13/8 to unstack, put a spare on the 8, spread checkers around to catch a blot (O is stacked so probably won't be able
    to clean up the blots), and hang back to maintain contact.

    Making a second anchor doesn't look bad though.

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

    If you're not going to make the 20pt anchor I suspect 6/4 is better than 13/8 as it's our heaviest stack.

    Stick

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Thu Sep 28 10:03:05 2023
    XGID=-----aE-Ba--dD---d-e-BA--A:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X X |
    | X O | | O X |
    | X O | | O |
    | X O | | O |
    | | X | O |
    | |BAR| |
    | | | X |
    | O | | X |
    | O | | X |
    | O X | | X |
    | O O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 187 O: 150 X-O: 0-0
    Cube: 1
    X to play 52

    A well-known general principle is that if you're far behind in the pip
    count then you typically want to stay back for more contact. The idea
    is to increase your chances of getting and hitting a shot, in order to
    turn the tables. That reasoning might suggest bar/23 13/8 (staying
    back as much as possible) or bar/20 6/4 (starting to build our board).
    However, XG thinks both of those plays are in whopper territory compared
    to making the second anchor. Why?

    I think the reason is that making the second anchor already gives X
    plenty of contact, and it puts a stop to several of O's joker rolls
    that unload his stacks on X's blots (if X doesn't anchor up). In the
    variant, I have moved X's existing anchor forward 3 pips, reducing
    contact. The rollout still favors anchoring up, but by a much
    narrower margin. The 5pt anchor and bar point anchor do not work
    well together.

    1. Rollout¹ Bar/20 22/20 eq:-0.306
    Player: 42.06% (G:9.37% B:0.30%)
    Opponent: 57.94% (G:11.53% B:0.37%)
    Confidence: ±0.015 (-0.321..-0.291) - [100.0%]

    2. Rollout¹ Bar/23 13/8 eq:-0.410 (-0.104)
    Player: 40.09% (G:9.54% B:0.35%)
    Opponent: 59.91% (G:16.33% B:0.63%)
    Confidence: ±0.018 (-0.428..-0.392) - [0.0%]

    3. Rollout¹ Bar/20 6/4 eq:-0.412 (-0.106)
    Player: 40.61% (G:9.40% B:0.34%)
    Opponent: 59.39% (G:16.81% B:0.65%)
    Confidence: ±0.017 (-0.428..-0.395) - [0.0%]

    ¹ 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.211.pre-release

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

    XGID=-----aE-Ba--dD---dBe--A--A:0:0:1:52:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O X | | O X |
    | X O X | | O |
    | X O | | O |
    | X O | | O |
    | | X | O |
    | |BAR| |
    | | | X |
    | O | | X |
    | O | | X |
    | O X | | X |
    | O O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 181 O: 150 X-O: 0-0
    Cube: 1
    X to play 52

    1. Rollout¹ Bar/20 22/20 eq:-0.346
    Player: 40.18% (G:8.16% B:0.26%)
    Opponent: 59.82% (G:9.71% B:0.28%)
    Confidence: ±0.010 (-0.356..-0.337) - [99.4%]

    2. Rollout¹ Bar/23 13/8 eq:-0.365 (-0.018)
    Player: 41.41% (G:9.82% B:0.31%)
    Opponent: 58.59% (G:16.45% B:0.69%)
    Confidence: ±0.010 (-0.375..-0.354) - [0.6%]

    ¹ 2592 Games rolled with Variance Reduction.
    Dice Seed: 271828
    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)