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  • My backgammon adage

    From pepstein5@gmail.com@21:1/5 to All on Mon Aug 30 12:56:57 2021
    Everyone loves the 5 point, but using the 8 to make the 5 (and thereby
    losing the 8) isn't such a stellar gain. So in these situations, look for something else to do. With 33, 6/3(2) (with 4 or more stacked on the 6) is better than 8/5(2).

    Paul

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  • From Timothy Chow@21:1/5 to peps...@gmail.com on Mon Aug 30 19:00:03 2021
    On 8/30/2021 3:56 PM, peps...@gmail.com wrote:
    Everyone loves the 5 point, but using the 8 to make the 5 (and thereby
    losing the 8) isn't such a stellar gain. So in these situations, look for something else to do. With 33, 6/3(2) (with 4 or more stacked on the 6) is better than 8/5(2).

    Here are a couple of third-roll positions where XG agrees with you.


    XGID=-b----E-C--AeD---bAdb---A-:0:0:1:33:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O X | | O O X |
    | X O | | O O |
    | X | | O |
    | X | | O |
    | | | |
    | |BAR| |
    | O | | X |
    | O | | X |
    | O 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: 159 O: 163 X-O: 0-0
    Cube: 1
    X to play 33

    1. Rollout¹ 24/18 6/3(2) eq:+0.357
    Player: 58.50% (G:15.11% B:0.51%)
    Opponent: 41.50% (G:9.34% B:0.35%)
    Confidence: ±0.007 (+0.351..+0.364) - [80.7%]

    2. Rollout¹ 24/18 13/10(2) eq:+0.353 (-0.004)
    Player: 58.70% (G:13.74% B:0.47%)
    Opponent: 41.30% (G:8.73% B:0.33%)
    Confidence: ±0.006 (+0.347..+0.359) - [19.3%]

    3. Rollout¹ 24/15 18/15 eq:+0.323 (-0.035)
    Player: 59.16% (G:9.48% B:0.33%)
    Opponent: 40.84% (G:8.76% B:0.28%)
    Confidence: ±0.006 (+0.316..+0.329) - [0.0%]

    4. Rollout¹ 24/18 8/5(2) eq:+0.310 (-0.047)
    Player: 57.15% (G:15.37% B:0.49%)
    Opponent: 42.85% (G:9.66% B:0.38%)
    Confidence: ±0.007 (+0.303..+0.317) - [0.0%]

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

    -------------------------------------------------------------------

    XGID=-a----E-C--aeD---c-e-A--AA:0:0:1:33:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X X |
    | X O | | O |
    | X O | | O |
    | X | | O |
    | | X | O |
    | |BAR| |
    | O | | X |
    | O | | X |
    | O X | | X |
    | O X | | X |
    | O O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 176 O: 157 X-O: 0-0
    Cube: 1
    X to play 33

    1. Rollout¹ Bar/22 24/21 6/3(2) eq:-0.021
    Player: 48.58% (G:12.86% B:0.41%)
    Opponent: 51.42% (G:9.71% B:0.39%)
    Confidence: ±0.008 (-0.029..-0.014) - [100.0%]

    2. Rollout¹ Bar/22 24/21 8/5(2) eq:-0.051 (-0.029)
    Player: 47.57% (G:13.76% B:0.36%)
    Opponent: 52.43% (G:10.09% B:0.41%)
    Confidence: ±0.008 (-0.059..-0.042) - [0.0%]

    3. Rollout¹ Bar/22 24/18 21/18 eq:-0.080 (-0.059)
    Player: 47.70% (G:11.25% B:0.33%)
    Opponent: 52.30% (G:11.39% B:0.45%)
    Confidence: ±0.008 (-0.088..-0.072) - [0.0%]

    4. Rollout¹ Bar/22 24/21 13/10(2) eq:-0.081 (-0.059)
    Player: 47.19% (G:12.41% B:0.42%)
    Opponent: 52.81% (G:10.53% B:0.44%)
    Confidence: ±0.008 (-0.089..-0.072) - [0.0%]

    ¹ 3888 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.207.pre-release

    -------------------------------------------------------------------

    But here's one where XG prefers the 5pt:


    XGID=-b----E-CA--eD---b-d---bAA:0:0:1:33:0:0:0:0:10

    X:Player 1 O:Player 2
    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 O | | O O |
    | X | | O |
    | X | | O |
    | | X | |
    | |BAR| |
    | O | | X |
    | O | | X |
    | O 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: 164 O: 157 X-O: 0-0
    Cube: 1
    X to play 33

    1. Rollout¹ Bar/22 8/5(3) eq:+0.157
    Player: 53.44% (G:19.36% B:1.04%)
    Opponent: 46.56% (G:15.64% B:0.72%)
    Confidence: ±0.008 (+0.149..+0.165) - [100.0%]

    2. Rollout¹ Bar/22 9/3 6/3 eq:+0.134 (-0.024)
    Player: 53.14% (G:16.75% B:0.85%)
    Opponent: 46.86% (G:14.56% B:0.52%)
    Confidence: ±0.007 (+0.126..+0.141) - [0.0%]

    3. Rollout¹ Bar/22 13/10 6/3(2) eq:+0.121 (-0.036)
    Player: 53.14% (G:18.08% B:1.08%)
    Opponent: 46.86% (G:16.60% B:1.05%)
    Confidence: ±0.007 (+0.114..+0.128) - [0.0%]

    4. Rollout² Bar/22 24/21 6/3(2) eq:+0.093 (-0.064)
    Player: 52.51% (G:15.95% B:0.94%)
    Opponent: 47.49% (G:15.38% B:0.64%)
    Confidence: ±0.013 (+0.080..+0.106) - [0.0%]

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

    ² 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From pepstein5@gmail.com@21:1/5 to Tim Chow on Mon Aug 30 16:03:43 2021
    On Tuesday, August 31, 2021 at 12:00:10 AM UTC+1, Tim Chow wrote:
    On 8/30/2021 3:56 PM, peps...@gmail.com wrote:
    Everyone loves the 5 point, but using the 8 to make the 5 (and thereby losing the 8) isn't such a stellar gain. So in these situations, look for something else to do. With 33, 6/3(2) (with 4 or more stacked on the 6) is better than 8/5(2).
    Here are a couple of third-roll positions where XG agrees with you.


    XGID=-b----E-C--AeD---bAdb---A-:0:0:1:33:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O X | | O O X |
    | X O | | O O |
    | X | | O |
    | X | | O |
    | | | |
    | |BAR| |
    | O | | X |
    | O | | X |
    | O 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: 159 O: 163 X-O: 0-0
    Cube: 1
    X to play 33

    1. Rollout¹ 24/18 6/3(2) eq:+0.357
    Player: 58.50% (G:15.11% B:0.51%)
    Opponent: 41.50% (G:9.34% B:0.35%)
    Confidence: ±0.007 (+0.351..+0.364) - [80.7%]

    2. Rollout¹ 24/18 13/10(2) eq:+0.353 (-0.004)
    Player: 58.70% (G:13.74% B:0.47%)
    Opponent: 41.30% (G:8.73% B:0.33%)
    Confidence: ±0.006 (+0.347..+0.359) - [19.3%]

    3. Rollout¹ 24/15 18/15 eq:+0.323 (-0.035)
    Player: 59.16% (G:9.48% B:0.33%)
    Opponent: 40.84% (G:8.76% B:0.28%)
    Confidence: ±0.006 (+0.316..+0.329) - [0.0%]

    4. Rollout¹ 24/18 8/5(2) eq:+0.310 (-0.047)
    Player: 57.15% (G:15.37% B:0.49%)
    Opponent: 42.85% (G:9.66% B:0.38%)
    Confidence: ±0.007 (+0.303..+0.317) - [0.0%]

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

    -------------------------------------------------------------------

    XGID=-a----E-C--aeD---c-e-A--AA:0:0:1:33:0:0:0:0:10

    X:Player 1 O:Player 2
    Score is X:0 O:0. Unlimited Game
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X O | | O X X |
    | X O | | O |
    | X O | | O |
    | X | | O |
    | | X | O |
    | |BAR| |
    | O | | X |
    | O | | X |
    | O X | | X |
    | O X | | X |
    | O O X | | X O |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 176 O: 157 X-O: 0-0
    Cube: 1
    X to play 33

    1. Rollout¹ Bar/22 24/21 6/3(2) eq:-0.021
    Player: 48.58% (G:12.86% B:0.41%)
    Opponent: 51.42% (G:9.71% B:0.39%)
    Confidence: ±0.008 (-0.029..-0.014) - [100.0%]

    2. Rollout¹ Bar/22 24/21 8/5(2) eq:-0.051 (-0.029)
    Player: 47.57% (G:13.76% B:0.36%)
    Opponent: 52.43% (G:10.09% B:0.41%)
    Confidence: ±0.008 (-0.059..-0.042) - [0.0%]

    3. Rollout¹ Bar/22 24/18 21/18 eq:-0.080 (-0.059)
    Player: 47.70% (G:11.25% B:0.33%)
    Opponent: 52.30% (G:11.39% B:0.45%)
    Confidence: ±0.008 (-0.088..-0.072) - [0.0%]

    4. Rollout¹ Bar/22 24/21 13/10(2) eq:-0.081 (-0.059)
    Player: 47.19% (G:12.41% B:0.42%)
    Opponent: 52.81% (G:10.53% B:0.44%)
    Confidence: ±0.008 (-0.089..-0.072) - [0.0%]

    ¹ 3888 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.207.pre-release

    -------------------------------------------------------------------

    But here's one where XG prefers the 5pt:


    XGID=-b----E-CA--eD---b-d---bAA:0:0:1:33:0:0:0:0:10

    X:Player 1 O:Player 2
    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 O | | O O |
    | X | | O |
    | X | | O |
    | | X | |
    | |BAR| |
    | O | | X |
    | O | | X |
    | O 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: 164 O: 157 X-O: 0-0
    Cube: 1
    X to play 33

    1. Rollout¹ Bar/22 8/5(3) eq:+0.157
    Player: 53.44% (G:19.36% B:1.04%)
    Opponent: 46.56% (G:15.64% B:0.72%)
    Confidence: ±0.008 (+0.149..+0.165) - [100.0%]

    2. Rollout¹ Bar/22 9/3 6/3 eq:+0.134 (-0.024)
    Player: 53.14% (G:16.75% B:0.85%)
    Opponent: 46.86% (G:14.56% B:0.52%)
    Confidence: ±0.007 (+0.126..+0.141) - [0.0%]

    3. Rollout¹ Bar/22 13/10 6/3(2) eq:+0.121 (-0.036)
    Player: 53.14% (G:18.08% B:1.08%)
    Opponent: 46.86% (G:16.60% B:1.05%)
    Confidence: ±0.007 (+0.114..+0.128) - [0.0%]

    4. Rollout² Bar/22 24/21 6/3(2) eq:+0.093 (-0.064)
    Player: 52.51% (G:15.95% B:0.94%)
    Opponent: 47.49% (G:15.38% B:0.64%)
    Confidence: ±0.013 (+0.080..+0.106) - [0.0%]

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

    ² 1296 Games rolled with Variance Reduction.
    Dice Seed: 271828
    Moves: 3-ply, cube decisions: XG Roller

    eXtreme Gammon Version: 2.19.207.pre-release

    ---
    Tim Chow
    Thanks for these.
    My own rule should be "When in doubt, don't make the 5 point" because
    it's far more often for my PR to suffer for making the 5 point rather than for not making it.
    (I know that Stick has given exactly the opposite rule.)

    Paul

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  • From J R@21:1/5 to peps...@gmail.com on Wed Sep 1 10:59:33 2021
    On Monday, August 30, 2021 at 3:56:58 PM UTC-4, peps...@gmail.com wrote:
    Everyone loves the 5 point, but using the 8 to make the 5 (and thereby
    losing the 8) isn't such a stellar gain. So in these situations, look for something else to do. With 33, 6/3(2) (with 4 or more stacked on the 6) is better than 8/5(2).

    Paul

    It's a bad adage. The few examples you'll scrape up are specifically dealing with double threes. If you have a normal
    [31] to play and you have to give up the 8pt of course you will. (because you won't be able to do so much with the roll otherwise)

    Stick

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