• Two checkers to scramble home

    From Timothy Chow@21:1/5 to All on Sun Feb 5 08:38:17 2023
    XGID=-bD-BBC--Bab------Ab-ccAb-:1:1:1:41:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X | | O O O X O |
    | | | O O O O |
    | | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X |
    | | | X X | +---+
    | O X | | X X X X O | | 2 |
    | O O X | | X X X X O | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 103 O: 126 X-O: 0-0
    Cube: 2, X own cube
    X to play 41

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah....Clem@21:1/5 to Timothy Chow on Sun Feb 5 18:58:32 2023
    On 2/5/2023 8:38 AM, Timothy Chow wrote:
    XGID=-bD-BBC--Bab------Ab-ccAb-:1:1:1:41:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
     +13-14-15-16-17-18------19-20-21-22-23-24-+
     |                X |   | O     O  O  X  O |
     |                  |   | O     O  O     O |
     |                  |   |       O  O       |
     |                  |   |                  |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |             X    |
     |                  |   | X           X    | +---+
     |    O     X       |   | X  X  X     X  O | | 2 |
     |    O  O  X       |   | X  X  X     X  O | +---+
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 103  O: 126 X-O: 0-0
    Cube: 2, X own cube
    X to play 41


    Playing off the 18 exposes a double direct shot. But O is still stuck on
    the ace point and her board is, shall we say, "poor". So it should be
    sound. The alternative is playing off the nine and that leaves a triple indirect shot some of which allow O to escape with tempo. Plus, the nine
    point may be worth something if O manages to upgrade her anchor to the
    three point.

    So, 18/13 for me.

    --
    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 All on Tue Feb 7 10:10:55 2023
    XGID=-bD-BBC--Bab------Ab-ccAb-:1:1:1:41:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X | | O O O X O |
    | | | O O O O |
    | | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X |
    | | | X X | +---+
    | O X | | X X X X O | | 2 |
    | O O X | | X X X X O | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 103 O: 126 X-O: 0-0
    Cube: 2, X own cube
    X to play 41

    Usually the idea in a scrambling position is to focus on advancing
    your stragglers, and not worry too much about exposing yourself to
    extra shots. Of course, there are limits to this strategy.

    Here, 18/13 doesn't create as many *extra* shots as it might seem
    at first, because O will hit with a 2 regardless. In the variant
    below, most of O's 2's don't hit if X plays 9/4, and the decision
    is much closer.

    1. Rollout¹ 18/13 eq:+0.330
    Player: 53.78% (G:18.80% B:2.07%)
    Opponent: 46.22% (G:14.74% B:0.31%)
    Confidence: ±0.011 (+0.318..+0.341) - [100.0%]

    2. Rollout¹ 9/4 eq:+0.239 (-0.091)
    Player: 51.93% (G:19.33% B:1.90%)
    Opponent: 48.07% (G:17.71% B:0.81%)
    Confidence: ±0.010 (+0.229..+0.249) - [0.0%]

    3. Rollout¹ 9/8 9/5 eq:+0.226 (-0.104)
    Player: 51.48% (G:18.88% B:1.85%)
    Opponent: 48.52% (G:17.61% B:0.79%)
    Confidence: ±0.011 (+0.215..+0.237) - [0.0%]

    4. Rollout¹ 9/5 6/5 eq:+0.220 (-0.110)
    Player: 51.41% (G:19.38% B:1.68%)
    Opponent: 48.59% (G:18.16% B:0.88%)
    Confidence: ±0.010 (+0.209..+0.230) - [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=-bD-BBC--Bab------Ab-bcAc-:1:1:1:41:0:0:0:0:10

    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X | | O O O X O |
    | | | O O O O |
    | | | O O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | X |
    | | | X X | +---+
    | O X | | X X X X O | | 2 |
    | O O X | | X X X X O | +---+
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 103 O: 123 X-O: 0-0
    Cube: 2, X own cube
    X to play 41

    1. Rollout¹ 18/13 eq:+0.564
    Player: 60.55% (G:20.82% B:1.99%)
    Opponent: 39.45% (G:8.95% B:0.18%)
    Confidence: ±0.008 (+0.556..+0.571) - [99.7%]

    2. Rollout¹ 9/4 eq:+0.548 (-0.016)
    Player: 60.23% (G:21.93% B:1.81%)
    Opponent: 39.77% (G:10.93% B:0.36%)
    Confidence: ±0.008 (+0.539..+0.556) - [0.2%]

    3. Rollout¹ 9/8 9/5 eq:+0.539 (-0.025)
    Player: 60.03% (G:20.95% B:1.84%)
    Opponent: 39.97% (G:10.89% B:0.37%)
    Confidence: ±0.008 (+0.531..+0.547) - [0.0%]

    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)
  • From Timothy Chow@21:1/5 to All on Wed Aug 16 08:50:23 2023
    XGID=-BBbB-BbB-C---A-ab-bbb-Ab-:1:-1:1:65:0:0:0:0:10

    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 O X O | +---+
    | O | | O O O O | | 2 |
    | | | | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | |
    | X X O | | X X O X X |
    | X X O | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 109 O: 137 X-O: 0-0
    Cube: 2, O own cube
    X to play 65

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah....Clem@21:1/5 to Timothy Chow on Wed Aug 16 14:01:14 2023
    On 8/16/2023 8:50 AM, Timothy Chow wrote:
    XGID=-BBbB-BbB-C---A-ab-bbb-Ab-:1:-1:1:65:0:0:0:0:10

    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  O     X  O | +---+
     |             O    |   | O  O  O        O | | 2 |
     |                  |   |                  | +---+
     |                  |   |                  |
     |                  |   |                  |
     |                  |BAR|                  |
     |                  |   |                  |
     |                  |   |                  |
     |       X          |   |                  |
     |       X     X  O |   | X     X  O  X  X |
     |       X     X  O |   | X     X  O  X  X |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 109  O: 137 X-O: 0-0
    Cube: 2, O own cube
    X to play 65


    With O's quasi backgame structure perhaps the pure play of slotting the
    five is best, but I'm unconvinced.

    I'll try 23/12 - escape the runner and leave the blot on the 14 as an
    indirect. She'll have to break the forward anchor to hit, so it looks playable.

    --
    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 All on Fri Aug 18 08:27:53 2023
    XGID=-BBbB-BbB-C---A-ab-bbb-Ab-:1:-1:1:65:0:0:0:0:10

    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 O X O | +---+
    | O | | O O O O | | 2 |
    | | | | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | |
    | X X O | | X X O X X |
    | X X O | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 109 O: 137 X-O: 0-0
    Cube: 2, O own cube
    X to play 65

    Like ah...clem, I played 23/12 here, and I am still startled at how
    bad XG thinks my play is. It thinks the only play is 23/18 14/8.
    I believe that this is a case where playing with one blot is much
    better than playing with two blots. That is not always the case,
    but here, if X plays 23/12, then O will be happy to break her 18pt
    to hit---not only does it give her good chances of picking up the
    second blot, but for timing reasons she wants to get some of those
    back checkers going anyway. By contrast, 23/18 14/8 creates a
    useful spare on the 8pt, and although O has plenty of ways to hit
    the remaining blot, they're not very good. XG estimates most of
    those hits to give O an equity in the +0.1 to +0.2 range. By
    contrast, after 23/12, most of O's hitting rolls have an equity
    in the +0.4 to +0.5 range (not to mention her super-joker rolls
    of 55 and 52).

    1. Rollout¹ 23/18 14/8 eq:+0.057
    Player: 57.94% (G:14.32% B:0.35%)
    Opponent: 42.06% (G:8.45% B:0.15%)
    Confidence: ±0.007 (+0.049..+0.064) - [100.0%]

    2. Rollout¹ 23/18 10/4 eq:-0.178 (-0.235)
    Player: 51.17% (G:14.50% B:0.43%)
    Opponent: 48.83% (G:16.02% B:0.44%)
    Confidence: ±0.007 (-0.185..-0.171) - [0.0%]

    3. Rollout¹ 23/12 eq:-0.231 (-0.288)
    Player: 50.83% (G:11.69% B:0.32%)
    Opponent: 49.17% (G:16.73% B:0.36%)
    Confidence: ±0.007 (-0.238..-0.225) - [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=-BBbB-BbB-C---Aaab-cbb-A--:1:-1:1:65:0:0:0:0:10

    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 O O X | +---+
    | O | | O O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | |
    | X X O | | X X O X X |
    | X X O | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 109 O: 151 X-O: 0-0
    Cube: 2, O own cube
    X to play 65

    1. Rollout¹ 23/12 eq:-0.179
    Player: 49.50% (G:14.52% B:0.48%)
    Opponent: 50.50% (G:12.00% B:0.43%)
    Confidence: ±0.007 (-0.187..-0.172) - [97.9%]

    2. Rollout¹ 23/18 14/8 eq:-0.190 (-0.011)
    Player: 48.03% (G:16.86% B:0.54%)
    Opponent: 51.97% (G:10.32% B:0.34%)
    Confidence: ±0.007 (-0.197..-0.183) - [2.1%]

    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)
  • From Stick Rice@21:1/5 to Timothy Chow on Wed Sep 27 07:26:38 2023
    On Friday, August 18, 2023 at 8:27:58 AM UTC-4, Timothy Chow wrote:
    XGID=-BBbB-BbB-C---A-ab-bbb-Ab-:1:-1:1:65:0:0:0:0:10

    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 O X O | +---+
    | O | | O O O O | | 2 |
    | | | | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | |
    | X X O | | X X O X X |
    | X X O | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 109 O: 137 X-O: 0-0
    Cube: 2, O own cube
    X to play 65
    Like ah...clem, I played 23/12 here, and I am still startled at how
    bad XG thinks my play is. It thinks the only play is 23/18 14/8.
    I believe that this is a case where playing with one blot is much
    better than playing with two blots. That is not always the case,
    but here, if X plays 23/12, then O will be happy to break her 18pt
    to hit---not only does it give her good chances of picking up the
    second blot, but for timing reasons she wants to get some of those
    back checkers going anyway. By contrast, 23/18 14/8 creates a
    useful spare on the 8pt, and although O has plenty of ways to hit
    the remaining blot, they're not very good. XG estimates most of
    those hits to give O an equity in the +0.1 to +0.2 range. By
    contrast, after 23/12, most of O's hitting rolls have an equity
    in the +0.4 to +0.5 range (not to mention her super-joker rolls
    of 55 and 52).

    1. Rollout¹ 23/18 14/8 eq:+0.057
    Player: 57.94% (G:14.32% B:0.35%)
    Opponent: 42.06% (G:8.45% B:0.15%)
    Confidence: ±0.007 (+0.049..+0.064) - [100.0%]

    2. Rollout¹ 23/18 10/4 eq:-0.178 (-0.235)
    Player: 51.17% (G:14.50% B:0.43%)
    Opponent: 48.83% (G:16.02% B:0.44%)
    Confidence: ±0.007 (-0.185..-0.171) - [0.0%]

    3. Rollout¹ 23/12 eq:-0.231 (-0.288)
    Player: 50.83% (G:11.69% B:0.32%)
    Opponent: 49.17% (G:16.73% B:0.36%)
    Confidence: ±0.007 (-0.238..-0.225) - [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=-BBbB-BbB-C---Aaab-cbb-A--:1:-1:1:65:0:0:0:0:10
    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 O O X | +---+
    | O | | O O O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | X | | |
    | X X O | | X X O X X |
    | X X O | | X X O X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 109 O: 151 X-O: 0-0
    Cube: 2, O own cube
    X to play 65
    1. Rollout¹ 23/12 eq:-0.179
    Player: 49.50% (G:14.52% B:0.48%)
    Opponent: 50.50% (G:12.00% B:0.43%)
    Confidence: ±0.007 (-0.187..-0.172) - [97.9%]

    2. Rollout¹ 23/18 14/8 eq:-0.190 (-0.011)
    Player: 48.03% (G:16.86% B:0.54%)
    Opponent: 51.97% (G:10.32% B:0.34%)
    Confidence: ±0.007 (-0.197..-0.183) - [2.1%]

    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

    I don't remember the exact problem since I've went through so many the past few days but I believe I commented on one of your posts noting that when the opponent has a strong board (it was a 4 point board like this one I think) it is so much worse to
    have two blots floating around rather than one. Again, one blot can survive being hit and eventually coming in with something good that maybe hops or if it hits we don't still have another man to pull off the bar. If we have two floating around ... the
    definition of bleak. The difference in number of shots between the best play and running all the way with my quick count is ... zero.

    Stick

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