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  • Dump two checkers?

    From Timothy Chow@21:1/5 to All on Mon Mar 20 08:53:48 2023
    XGID=---bBBEaB--B-B---abcbca---:1:-1:1:54:0:0:0:0:10

    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 O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X X X O |
    | X X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 112 O: 127 X-O: 0-0
    Cube: 2, O own cube
    X to play 54

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Timothy Chow on Mon Mar 20 07:28:50 2023
    On Monday, March 20, 2023 at 8:54:21 AM UTC-4, Timothy Chow wrote:
    XGID=---bBBEaB--B-B---abcbca---:1:-1:1:54:0:0:0:0:10

    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 O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X X X O |
    | X X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 112 O: 127 X-O: 0-0
    Cube: 2, O own cube
    X to play 54

    ---
    Tim Chow

    After dumping two checkers inside, O's plan will be to improve her board on this roll, sit back with the blot on her 18 point, and look for an opportunity to hit as we break the stripped outfield. We won't hit her for the next roll or two with the inner
    board sitting ducks. Play 11/6, 11/7 now. It's risky with 10 return shots on our blot on 7, and it makes an ugly stack on the 6, but we'll have a shot in O's board, not much trouble coming in, and maintain some outfield control. Probably worth the risk.
    Over the board, I would have been all in on dumping the checkers, without a second thought.

    11/6, 11/7

    Bob

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stick Rice@21:1/5 to Robert Zimmerman on Mon Mar 20 13:27:55 2023
    On Monday, March 20, 2023 at 10:28:51 AM UTC-4, Robert Zimmerman wrote:
    On Monday, March 20, 2023 at 8:54:21 AM UTC-4, Timothy Chow wrote:
    XGID=---bBBEaB--B-B---abcbca---:1:-1:1:54:0:0:0:0:10

    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 O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X X X O |
    | X X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 112 O: 127 X-O: 0-0
    Cube: 2, O own cube
    X to play 54

    ---
    Tim Chow
    After dumping two checkers inside, O's plan will be to improve her board on this roll, sit back with the blot on her 18 point, and look for an opportunity to hit as we break the stripped outfield. We won't hit her for the next roll or two with the
    inner board sitting ducks. Play 11/6, 11/7 now. It's risky with 10 return shots on our blot on 7, and it makes an ugly stack on the 6, but we'll have a shot in O's board, not much trouble coming in, and maintain some outfield control. Probably worth the
    risk.
    Over the board, I would have been all in on dumping the checkers, without a second thought.

    11/6, 11/7

    Bob

    If you're going to hit wouldn't 13/8 be a much better five?

    The obvious variants here are the opp's inner board blot lifted and the opp's inner board blot covered.

    Stick

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Stick Rice on Mon Mar 20 15:34:12 2023
    On Monday, March 20, 2023 at 4:27:58 PM UTC-4, Stick Rice wrote:
    On Monday, March 20, 2023 at 10:28:51 AM UTC-4, Robert Zimmerman wrote:
    On Monday, March 20, 2023 at 8:54:21 AM UTC-4, Timothy Chow wrote:
    XGID=---bBBEaB--B-B---abcbca---:1:-1:1:54:0:0:0:0:10

    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 O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X X X O |
    | X X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 112 O: 127 X-O: 0-0
    Cube: 2, O own cube
    X to play 54

    ---
    Tim Chow
    After dumping two checkers inside, O's plan will be to improve her board on this roll, sit back with the blot on her 18 point, and look for an opportunity to hit as we break the stripped outfield. We won't hit her for the next roll or two with the
    inner board sitting ducks. Play 11/6, 11/7 now. It's risky with 10 return shots on our blot on 7, and it makes an ugly stack on the 6, but we'll have a shot in O's board, not much trouble coming in, and maintain some outfield control. Probably worth the
    risk.
    Over the board, I would have been all in on dumping the checkers, without a second thought.

    11/6, 11/7

    Bob
    If you're going to hit wouldn't 13/8 be a much better five?

    The obvious variants here are the opp's inner board blot lifted and the opp's inner board blot covered.

    Stick

    On closer inspection, yeah. After 13/8 X would be favored to have a very good reply after being hit by O. Bon point.
    Bob

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Wed Mar 22 09:57:37 2023
    XGID=---bBBEaB--B-B---abcbca---:1:-1:1:54:0:0:0:0:10

    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 O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X X X O |
    | X X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 112 O: 127 X-O: 0-0
    Cube: 2, O own cube
    X to play 54

    I don't think I seriously considered dumping two checkers here.
    But I played 11/7* 11/6, thinking that I didn't want to leave
    three blots in the outfield if things went wrong. However, if
    O hits back then X is going to be in big trouble regardless,
    while 13/8 11/7* clearly has more upside if X is missed.

    This is perhaps an instructive position for something that was
    discussed here on r.g.b. recently, namely, does it matter if you
    roll out a position with a missed double? Suppose that we change
    the position by giving X the cube, and we assume that X missed a
    double before the roll. Then we find that XG recommends 11/6 11/7*.

    For the variant, I have strengthened O's board to the point where
    XG favors dumping two.

    1. Rollout¹ 13/8 11/7* eq:+0.492
    Player: 74.71% (G:13.53% B:0.85%)
    Opponent: 25.29% (G:6.45% B:0.38%)
    Confidence: ±0.006 (+0.486..+0.499) - [100.0%]

    2. Rollout¹ 11/6 11/7* eq:+0.413 (-0.079)
    Player: 71.01% (G:14.84% B:0.85%)
    Opponent: 28.99% (G:5.69% B:0.23%)
    Confidence: ±0.007 (+0.407..+0.420) - [0.0%]

    3. Rollout¹ 6/2 6/1 eq:+0.362 (-0.130)
    Player: 70.01% (G:8.47% B:0.22%)
    Opponent: 29.99% (G:4.31% B:0.13%)
    Confidence: ±0.005 (+0.356..+0.367) - [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=---bBBEaB--B-B---abcbb-b--:1:-1:1:54:0:0:0:0:10

    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 O | | 2 |
    | | | O | +---+
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | | | X |
    | | | X |
    | X X | | X X X O |
    | X X O | | X X X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 112 O: 124 X-O: 0-0
    Cube: 2, O own cube
    X to play 54

    1. Rollout¹ 6/2 6/1 eq:+0.340
    Player: 69.59% (G:7.07% B:0.17%)
    Opponent: 30.41% (G:3.96% B:0.11%)
    Confidence: ±0.006 (+0.333..+0.346) - [100.0%]

    2. Rollout¹ 13/8 11/7* eq:+0.322 (-0.018)
    Player: 70.53% (G:9.25% B:0.34%)
    Opponent: 29.47% (G:9.97% B:0.56%)
    Confidence: ±0.005 (+0.317..+0.327) - [0.0%]

    3. Rollout¹ 11/6 11/7* eq:+0.298 (-0.042)
    Player: 68.06% (G:11.41% B:0.45%)
    Opponent: 31.94% (G:6.89% B:0.21%)
    Confidence: ±0.008 (+0.290..+0.305) - [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

    ---
    Tim Chow

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