• 4pt vs 7pt 2

    From Timothy Chow@21:1/5 to All on Tue Jun 13 09:02:53 2023
    XGID=-----bEAD---bC---bbeb--AA-:0:0:1:22:0:0:0:0:10

    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 |
    | X O O | | O O |
    | X | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X |
    | O X | | X O |
    | O X X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 155 O: 136 X-O: 0-0
    Cube: 1
    X to play 22

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ah....Clem@21:1/5 to Timothy Chow on Tue Jun 13 11:59:29 2023
    On 6/13/2023 9:02 AM, Timothy Chow wrote:
    XGID=-----bEAD---bC---bbeb--AA-:0:0:1:22:0:0:0:0:10

    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 |
     | X           O  O |   | O  O             |
     | X                |   | O                |
     |                  |   | O                |
     |                  |   | O                |
     |                  |BAR|                  |
     |                  |   | X                |
     |             X    |   | X                |
     |             X    |   | X                |
     | O           X    |   | X  O             |
     | O           X  X |   | X  O             |
     +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count  X: 155  O: 136 X-O: 0-0
    Cube: 1
    X to play 22


    XG tends to like keeping checkers in front of the anchor, especially
    when behind in the race. And making the four point leaves the blot on
    the seven exposed. So I'll make the bar and then slot the four since I
    want to hang back for more contact this far behind in the race.

    13/7 6/4.

    --
    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 Thu Jun 15 09:26:52 2023
    XGID=-----bEAD---bC---bbeb--AA-:0:0:1:22:0:0:0:0:10

    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 |
    | X O O | | O O |
    | X | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X |
    | O X | | X O |
    | O X X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 155 O: 136 X-O: 0-0
    Cube: 1
    X to play 22

    Covering the blot seems natural, but let's think about the alternative
    of making the 4pt. After 6/4(2), we're going to play 23/21 with one of
    our remaining 2's. O's 2's will then be duplicated; she won't hit our
    bar point blot except with her 22 joker or with 52 or 62, and 52 and 62
    are not very good rolls for her. In general, a blot in front of a high
    anchor is usually not in as much danger as an average blot, and the bar
    point is of less value than average when the opponent has a high anchor.
    So covering with 13/7 is not automatic.

    But does that mean we should make the 4pt? Notice that either way, we
    are going to have blots in the opponent's board that are vulnerable to
    attack. Making our own 4pt provides some protection in case of a blot-
    hitting contest. I think that's what swings the balance in favor of
    making the 4pt. See the variant below, in which we can anchor with
    one of our 2's and are much less vulnerable to being attacked.

    1. Rollout¹ 23/21 8/4 6/4 eq:-0.841
    Player: 32.70% (G:6.11% B:0.27%)
    Opponent: 67.30% (G:25.29% B:1.00%)
    Confidence: ±0.017 (-0.857..-0.824) - [100.0%]

    2. Rollout¹ 23/21 13/7 eq:-0.915 (-0.075)
    Player: 30.95% (G:5.74% B:0.22%)
    Opponent: 69.05% (G:24.84% B:0.78%)
    Confidence: ±0.017 (-0.932..-0.898) - [0.0%]

    3. Rollout¹ 24/22 23/21 6/4(2) eq:-0.916 (-0.076)
    Player: 32.43% (G:5.69% B:0.25%)
    Opponent: 67.57% (G:27.68% B:0.98%)
    Confidence: ±0.015 (-0.931..-0.901) - [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=-----bEAD---bC---bbeb-A-A-:0:0:1:22:0:0:0:0:10

    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 |
    | X O O | | O O |
    | X | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X | | X |
    | O X | | X O |
    | O X X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 154 O: 136 X-O: 0-0
    Cube: 1
    X to play 22

    1. Rollout¹ 24/22 13/7 eq:-0.556
    Player: 35.00% (G:5.67% B:0.21%)
    Opponent: 65.00% (G:10.78% B:0.40%)
    Confidence: ±0.013 (-0.568..-0.543) - [72.7%]

    2. Rollout¹ 24/22 8/4 6/4 eq:-0.561 (-0.005)
    Player: 35.34% (G:6.10% B:0.25%)
    Opponent: 64.66% (G:12.59% B:0.47%)
    Confidence: ±0.013 (-0.574..-0.549) - [27.3%]

    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)