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  • 5a5a, 2-4-5 backgame, 11 to play

    From ah...Clem@21:1/5 to All on Thu Jun 8 18:03:49 2023
    Bar point? Nine point? Eleven point? Something else?

    XGID=--b-bcE-D-C-AB---c-e------:0:0:1:11:0:0:0:5:10

    X:You O:O
    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O |
    | X O | | O |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 202 X-O: 0-0/5
    Cube: 1
    X to play 11

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  • From Timothy Chow@21:1/5 to ah...Clem on Thu Jun 8 20:40:39 2023
    On 6/8/2023 6:03 PM, ah...Clem wrote:
    Bar point? Nine point? Eleven point? Something else?

    XGID=--b-bcE-D-C-AB---c-e------:0:0:1:11:0:0:0:5:10

    X:You O:O
    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O |
    | X O | | O |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 202 X-O: 0-0/5
    Cube: 1
    X to play 11

    I'd play 10/9(2) 8/7(2), making a solid four-prime. Generally the
    right strategy against a backgame is to prime the back checkers.
    O has good timing here, so our priming strategy may not work, but
    I don't see another approach that's superior. Trying to avoid
    blots seems like a lost cause. We don't really mind if we're hit
    since O has no board and it will just improve our own timing.

    ---
    Tim Chow

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  • From ah....Clem@21:1/5 to All on Sun Jun 11 11:13:13 2023
    On 6/8/2023 6:03 PM, ah...Clem wrote:

    Tim gives a very good analysis of this position, and his choice of
    making the 9 and 7 points is XG's 3-ply choice. But stronger settings
    have that play as an error.

    The acronym WWJD comes to mind, where the J stands for Jeremy.

    I'm not sure if the is technically a Bagai position, but offering up two
    blots instead of one wins the rollout by .048. Of course, there's the possibility that XG doesn't understand this position so the more normal
    looking play might actually be better. I don't play enough three point backgames to have a sense.

    I played it safe by making the 12 and 7 points, leaving no blots, but
    that's unnecessarily safe and a double whopper.

    In the variant, I've given O her five point and the stronger board makes
    the two-blot play an error, with my safe play still a whopper.

    XGID=--b-bcE-D-C-AB---c-e------:0:0:1:11:0:0:0:5:10

    X:You O:O
    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O |
    | X O | | O |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 202 X-O: 0-0/5
    Cube: 1
    X to play 11

    1. Rollout¹ 12/11 10/9 8/7(2) eq:+0.508
    Player: 59.38% (G:23.41% B:1.14%)
    Opponent: 40.62% (G:8.60% B:0.41%)
    Confidence: ±0.021 (+0.488..+0.529) - [100.0%]
    Duration: 10 minutes 13 seconds

    2. Rollout¹ 10/9(2) 8/7(2) eq:+0.460 (-0.048)
    Player: 58.05% (G:24.25% B:1.08%)
    Opponent: 41.95% (G:8.26% B:0.29%)
    Confidence: ±0.018 (+0.442..+0.478) - [0.0%]
    Duration: 7 minutes 54 seconds

    3. Rollout¹ 13/12 10/9 8/7(2) eq:+0.443 (-0.065)
    Player: 57.58% (G:23.83% B:1.17%)
    Opponent: 42.42% (G:8.41% B:0.36%)
    Confidence: ±0.019 (+0.424..+0.462) - [0.0%]
    Duration: 7 minutes 21 seconds

    4. Rollout¹ 13/11 8/7(2) eq:+0.377 (-0.131)
    Player: 56.37% (G:23.51% B:0.93%)
    Opponent: 43.63% (G:8.85% B:0.39%)
    Confidence: ±0.019 (+0.358..+0.396) - [0.0%]
    Duration: 7 minutes 45 seconds

    5. Rollout¹ 12/9 10/9 eq:+0.364 (-0.144)
    Player: 56.16% (G:22.60% B:0.86%)
    Opponent: 43.84% (G:9.07% B:0.39%)
    Confidence: ±0.019 (+0.344..+0.383) - [0.0%]
    Duration: 7 minutes 48 seconds

    6. Rollout¹ 13/12(2) 8/7(2) eq:+0.308 (-0.201)
    Player: 54.67% (G:21.94% B:0.99%)
    Opponent: 45.33% (G:8.84% B:0.44%)
    Confidence: ±0.019 (+0.288..+0.327) - [0.0%]
    Duration: 8 minutes 18 seconds


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


    eXtreme Gammon Version: 2.10, MET: Kazaross XG2


    //////////////
    //variant
    //////////////

    Give O her five point and the two-blot play is a .04 error.

    XGID=--b-bcE-D-C-AB---c-cb-----:0:0:1:11:0:0:0:5:10

    X:Player 1 O:Player 2
    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O |
    | X O | | O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 200 X-O: 0-0/5
    Cube: 1
    X to play 11

    1. XG Roller++ 10/9(2) 8/7(2) eq:+0.392
    Player: 57.18% (G:22.12% B:0.84%)
    Opponent: 42.82% (G:9.10% B:0.42%)

    2. XG Roller++ 13/12 10/9 8/7(2) eq:+0.350 (-0.041)
    Player: 56.42% (G:21.24% B:0.84%)
    Opponent: 43.58% (G:9.52% B:0.41%)

    3. XG Roller++ 13/12(2) 8/7(2) eq:+0.276 (-0.116)
    Player: 54.15% (G:21.07% B:0.74%)
    Opponent: 45.85% (G:9.39% B:0.40%)

    4. 4-ply 12/9 10/9 eq:+0.310 (-0.082)
    Player: 55.07% (G:21.47% B:0.81%)
    Opponent: 44.93% (G:9.49% B:0.42%)

    5. 4-ply 12/10 8/7(2) eq:+0.277 (-0.115)
    Player: 54.13% (G:21.48% B:0.79%)
    Opponent: 45.87% (G:9.73% B:0.43%)


    eXtreme Gammon Version: 2.10, MET: Kazaross XG2





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

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    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to ah....Clem on Mon Jun 12 08:55:08 2023
    On 6/11/2023 11:13 AM, ah....Clem wrote:
    The acronym WWJD comes to mind, where the J stands for Jeremy.

    I'm not sure if the is technically a Bagai position, but offering up two blots instead of one wins the rollout by .048.

    I have a somewhat more liberal definition of a "Bagai position" than
    Stick does, but I certainly wouldn't use that term to refer to a
    backgame position. This play is what I (following Trice) would call
    an "early blot" play. We slot points in our prime, not worrying about
    getting hit, since the hit checkers will have no trouble escaping,
    and getting hit will improve our timing.

    Here's a rollout with slightly stronger settings, which yields the
    same qualitative verdict, though maybe with a slightly smaller
    equity difference.

    XGID=--b-bcE-D-C-AB---c-e------:0:0:1:11:0:0:0:5:10

    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O |
    | X O | | O |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 202 X-O: 0-0/5
    Cube: 1
    X to play 11

    1. Rollout¹ 12/11 10/9 8/7(2) eq:+0.485
    Player: 59.23% (G:22.99% B:1.18%)
    Opponent: 40.77% (G:8.62% B:0.50%)
    Confidence: ±0.010 (+0.475..+0.495) - [100.0%]

    2. Rollout¹ 10/9(2) 8/7(2) eq:+0.448 (-0.037)
    Player: 58.10% (G:23.80% B:0.94%)
    Opponent: 41.90% (G:8.53% B:0.38%)
    Confidence: ±0.010 (+0.437..+0.458) - [0.0%]

    ¹ 2592 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 4-ply, cube decisions: XG Roller+
    Search interval: Large

    eXtreme Gammon Version: 2.19.211.pre-release, MET: Kazaross XG2

    ---
    Tim Chow

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  • From Stick Rice@21:1/5 to ah....Clem on Wed Jun 28 07:55:47 2023
    On Sunday, June 11, 2023 at 11:13:13 AM UTC-4, ah....Clem wrote:
    On 6/8/2023 6:03 PM, ah...Clem wrote:
    Tim gives a very good analysis of this position, and his choice of
    making the 9 and 7 points is XG's 3-ply choice. But stronger settings
    have that play as an error.

    The acronym WWJD comes to mind, where the J stands for Jeremy.

    I'm not sure if the is technically a Bagai position, but offering up two blots instead of one wins the rollout by .048. Of course, there's the possibility that XG doesn't understand this position so the more normal looking play might actually be better. I don't play enough three point backgames to have a sense.

    I played it safe by making the 12 and 7 points, leaving no blots, but
    that's unnecessarily safe and a double whopper.

    In the variant, I've given O her five point and the stronger board makes
    the two-blot play an error, with my safe play still a whopper. XGID=--b-bcE-D-C-AB---c-e------:0:0:1:11:0:0:0:5:10

    X:You O:O
    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O |
    | X O | | O |
    | O | | O |
    | | | O |
    | | | O |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 202 X-O: 0-0/5
    Cube: 1
    X to play 11
    1. Rollout¹ 12/11 10/9 8/7(2) eq:+0.508
    Player: 59.38% (G:23.41% B:1.14%)
    Opponent: 40.62% (G:8.60% B:0.41%)
    Confidence: ±0.021 (+0.488..+0.529) - [100.0%]
    Duration: 10 minutes 13 seconds

    2. Rollout¹ 10/9(2) 8/7(2) eq:+0.460 (-0.048)
    Player: 58.05% (G:24.25% B:1.08%)
    Opponent: 41.95% (G:8.26% B:0.29%)
    Confidence: ±0.018 (+0.442..+0.478) - [0.0%]
    Duration: 7 minutes 54 seconds

    3. Rollout¹ 13/12 10/9 8/7(2) eq:+0.443 (-0.065)
    Player: 57.58% (G:23.83% B:1.17%)
    Opponent: 42.42% (G:8.41% B:0.36%)
    Confidence: ±0.019 (+0.424..+0.462) - [0.0%]
    Duration: 7 minutes 21 seconds

    4. Rollout¹ 13/11 8/7(2) eq:+0.377 (-0.131)
    Player: 56.37% (G:23.51% B:0.93%)
    Opponent: 43.63% (G:8.85% B:0.39%)
    Confidence: ±0.019 (+0.358..+0.396) - [0.0%]
    Duration: 7 minutes 45 seconds

    5. Rollout¹ 12/9 10/9 eq:+0.364 (-0.144)
    Player: 56.16% (G:22.60% B:0.86%)
    Opponent: 43.84% (G:9.07% B:0.39%)
    Confidence: ±0.019 (+0.344..+0.383) - [0.0%]
    Duration: 7 minutes 48 seconds

    6. Rollout¹ 13/12(2) 8/7(2) eq:+0.308 (-0.201)
    Player: 54.67% (G:21.94% B:0.99%)
    Opponent: 45.33% (G:8.84% B:0.44%)
    Confidence: ±0.019 (+0.288..+0.327) - [0.0%]
    Duration: 8 minutes 18 seconds


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


    eXtreme Gammon Version: 2.10, MET: Kazaross XG2


    //////////////
    //variant
    //////////////

    Give O her five point and the two-blot play is a .04 error.

    XGID=--b-bcE-D-C-AB---c-cb-----:0:0:1:11:0:0:0:5:10

    X:Player 1 O:Player 2
    Score is X:0 O:0 5 pt.(s) match.
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O O |
    | X O | | O O |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | X |
    | X | | X |
    | X X | | X O |
    | X X | | X O O O |
    | X X X | | X O O O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 130 O: 200 X-O: 0-0/5
    Cube: 1
    X to play 11
    1. XG Roller++ 10/9(2) 8/7(2) eq:+0.392
    Player: 57.18% (G:22.12% B:0.84%)
    Opponent: 42.82% (G:9.10% B:0.42%)

    2. XG Roller++ 13/12 10/9 8/7(2) eq:+0.350 (-0.041)
    Player: 56.42% (G:21.24% B:0.84%)
    Opponent: 43.58% (G:9.52% B:0.41%)

    3. XG Roller++ 13/12(2) 8/7(2) eq:+0.276 (-0.116)
    Player: 54.15% (G:21.07% B:0.74%)
    Opponent: 45.85% (G:9.39% B:0.40%)

    4. 4-ply 12/9 10/9 eq:+0.310 (-0.082)
    Player: 55.07% (G:21.47% B:0.81%)
    Opponent: 44.93% (G:9.49% B:0.42%)

    5. 4-ply 12/10 8/7(2) eq:+0.277 (-0.115)
    Player: 54.13% (G:21.48% B:0.79%)
    Opponent: 45.87% (G:9.73% B:0.43%)


    eXtreme Gammon Version: 2.10, MET: Kazaross XG2





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

    This has nothing to do with a Bagai position. I'll cover what it is soon over on BGO.

    Stick

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