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  • Run the back checker?

    From Timothy Chow@21:1/5 to All on Mon Feb 20 09:51:46 2023
    XGID=-a----E-D---dC-b--ceB---A-:0:0:1:62:0:0:0:0:10

    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 X |
    | X O O | | O X |
    | X O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 165 O: 147 X-O: 0-0
    Cube: 1
    X to play 62

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Zimmerman@21:1/5 to Timothy Chow on Mon Feb 20 07:30:09 2023
    On Monday, February 20, 2023 at 9:51:47 AM UTC-5, Timothy Chow wrote:
    XGID=-a----E-D---dC-b--ceB---A-:0:0:1:62:0:0:0:0:10

    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 X |
    | X O O | | O X |
    | X O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 165 O: 147 X-O: 0-0
    Cube: 1
    X to play 62

    ---
    Tim Chow

    The board is setting up as a holding game, but I would also try to attack O's back checker and try to get out of the holding game. A holding game with a goal keeper (I think that's what I've seen the back checker called before) can look better than
    without, and running will give that up, but I would think the goalkeeper more valuable if O were more stacked and poorly distributed. With the 10 point made, O is doing ok and may not run into problems coming in.

    Committing to a holding game right now cedes the advantage to O. Here it's still early in the game, and there's room for maneuvering for X to build some advantage. Running with the back checker can provide some outfield coverage against O's attempt to
    run, and it can become a builder in an attacking/priming effort on that blot. And if we later roll some good doubles, we might even the race. If hit in the outfield, we can return to the holding game. Nothing will have been lost in the race since we were
    already behind by 18 pips.

    24/16 for me.
    Bob

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stick Rice@21:1/5 to Timothy Chow on Mon Feb 20 14:03:25 2023
    On Monday, February 20, 2023 at 9:51:47 AM UTC-5, Timothy Chow wrote:
    XGID=-a----E-D---dC-b--ceB---A-:0:0:1:62:0:0:0:0:10

    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 X |
    | X O O | | O X |
    | X O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 165 O: 147 X-O: 0-0
    Cube: 1
    X to play 62

    ---
    Tim Chow

    Variant: opp's rear checker moved forward two pips.

    Stick

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to All on Wed Feb 22 11:51:42 2023
    XGID=-a----E-D---dC-b--ceB---A-:0:0:1:62:0:0:0:0:10

    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 X |
    | X O O | | O X |
    | X O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 165 O: 147 X-O: 0-0
    Cube: 1
    X to play 62

    My variant is different from Stick's suggestion. Part of the point
    here is that the most plausible alternative to running 24/16 is the
    slotting play 13/5, which isn't particularly attractive. It strips
    the midpoint and doesn't do a particularly good job of containing
    O's straggler.

    1. Rollout¹ 24/16 eq:-0.292
    Player: 41.55% (G:8.49% B:0.25%)
    Opponent: 58.45% (G:8.81% B:0.35%)
    Confidence: ±0.012 (-0.304..-0.279) - [100.0%]

    2. Rollout¹ 13/5 eq:-0.394 (-0.102)
    Player: 39.77% (G:9.74% B:0.26%)
    Opponent: 60.23% (G:12.00% B:0.47%)
    Confidence: ±0.014 (-0.408..-0.380) - [0.0%]

    3. Rollout¹ 13/11 8/2 eq:-0.405 (-0.113)
    Player: 39.69% (G:9.37% B:0.27%)
    Opponent: 60.31% (G:13.70% B:0.66%)
    Confidence: ±0.015 (-0.420..-0.390) - [0.0%]

    4. Rollout¹ 24/22 8/2 eq:-0.429 (-0.138)
    Player: 38.72% (G:8.03% B:0.23%)
    Opponent: 61.28% (G:11.41% B:0.41%)
    Confidence: ±0.013 (-0.442..-0.416) - [0.0%]

    5. Rollout¹ 24/22 13/7 eq:-0.435 (-0.143)
    Player: 38.69% (G:8.31% B:0.22%)
    Opponent: 61.31% (G:11.56% B:0.39%)
    Confidence: ±0.013 (-0.448..-0.422) - [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=-a----E-C---dD-b-c-eB---A-:0:0:1:62:0:0:0:0:10

    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 X |
    | X O O | | O X |
    | X O | | O |
    | X | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | O | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 170 O: 150 X-O: 0-0
    Cube: 1
    X to play 62

    1. Rollout¹ 13/11 13/7 eq:-0.301
    Player: 42.20% (G:10.70% B:0.32%)
    Opponent: 57.80% (G:13.49% B:0.57%)
    Confidence: ±0.008 (-0.308..-0.293) - [89.7%]

    2. Rollout¹ 24/16 eq:-0.309 (-0.008)
    Player: 41.22% (G:8.58% B:0.26%)
    Opponent: 58.78% (G:9.63% B:0.37%)
    Confidence: ±0.007 (-0.316..-0.302) - [5.3%]

    3. Rollout¹ 13/5 eq:-0.309 (-0.009)
    Player: 41.62% (G:10.56% B:0.31%)
    Opponent: 58.38% (G:12.23% B:0.50%)
    Confidence: ±0.008 (-0.317..-0.302) - [5.0%]

    4. Rollout¹ 24/18 13/11 eq:-0.322 (-0.021)
    Player: 41.13% (G:9.08% B:0.31%)
    Opponent: 58.87% (G:11.08% B:0.44%)
    Confidence: ±0.007 (-0.329..-0.315) - [0.0%]

    5. Rollout¹ 13/7 6/4 eq:-0.339 (-0.038)
    Player: 41.76% (G:10.28% B:0.33%)
    Opponent: 58.25% (G:14.63% B:0.69%)
    Confidence: ±0.008 (-0.347..-0.331) - [0.0%]

    ¹ 5184 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.211.pre-release

    ---------------
    Stick's variant
    ---------------

    XGID=---a--E-D---dC-b--ceB---A-:0:0:1:62:0:0:0:0:10

    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 X |
    | X O O | | O X |
    | X O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X |
    | O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 165 O: 145 X-O: 0-0
    Cube: 1
    X to play 62

    1. Rollout¹ 24/16 eq:-0.386
    Player: 39.01% (G:7.34% B:0.22%)
    Opponent: 60.99% (G:8.50% B:0.31%)
    Confidence: ±0.006 (-0.392..-0.380) - [90.7%]

    2. Rollout¹ 13/11 8/2 eq:-0.393 (-0.007)
    Player: 39.09% (G:9.50% B:0.22%)
    Opponent: 60.91% (G:10.96% B:0.50%)
    Confidence: ±0.008 (-0.401..-0.385) - [9.3%]

    3. Rollout¹ 13/5 eq:-0.408 (-0.021)
    Player: 39.08% (G:9.27% B:0.26%)
    Opponent: 60.92% (G:11.51% B:0.47%)
    Confidence: ±0.007 (-0.415..-0.400) - [0.0%]

    ¹ 5184 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)