• Which point, how to point or not to point?

    From Axel Reichert@21:1/5 to All on Fri Dec 23 19:39:37 2022
    GNU Backgammon Position ID: aLeDAxDYTvATAA
    Match ID : cIkuAAAAAAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | O O O | | O O X X | 0 points
    | O O | | O O X |
    | O | | O X |
    | | | X |
    | | | 6 |
    | |BAR| |v 1 point match
    | | | |
    | | | |
    | X | | O |
    | X X X | | O | Rolled 53
    | O X X X | | X O | 0 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 132, X 137

    Can also be rephrased as "How many blots and where?"

    Best regards

    Axel

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  • From Timothy Chow@21:1/5 to Axel Reichert on Sat Dec 24 07:46:19 2022
    On 12/23/2022 1:39 PM, Axel Reichert wrote:
    GNU Backgammon Position ID: aLeDAxDYTvATAA
    Match ID : cIkuAAAAAAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | O O O | | O O X X | 0 points
    | O O | | O O X |
    | O | | O X |
    | | | X |
    | | | 6 |
    | |BAR| |v 1 point match
    | | | |
    | | | |
    | X | | O |
    | X X X | | O | Rolled 53
    | O X X X | | X O | 0 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 132, X 137

    Can also be rephrased as "How many blots and where?"

    X is slightly behind in the race. If he were well ahead in the
    race, then I would play safe with 15/10 8/5. If he were well
    behind in the race then I think I would risk a direct shot for
    the sake of better containment; 13/8 13/10 looks better to me
    than 8/3 6/3, because it blocks sixes and also makes it easier
    for X to extend his prime.

    Given that X is slightly behind in the race, I'm not sure which
    of these two strategies is better. The "safe" play still gives
    O four hitting rolls. Still, I think I would play safe, since
    getting hit is pretty bad.

    ---
    Tim Chow

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  • From ah....Clem@21:1/5 to Axel Reichert on Sat Dec 24 11:56:06 2022
    On 12/23/2022 1:39 PM, Axel Reichert wrote:
    GNU Backgammon Position ID: aLeDAxDYTvATAA
    Match ID : cIkuAAAAAAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | O O O | | O O X X | 0 points
    | O O | | O O X |
    | O | | O X |
    | | | X |
    | | | 6 |
    | |BAR| |v 1 point match
    | | | |
    | | | |
    | X | | O |
    | X X X | | O | Rolled 53
    | O X X X | | X O | 0 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 132, X 137

    Can also be rephrased as "How many blots and where?"

    Race is about even and O has a strong board so 15/10 8/5 for me. We can
    make more points later and O still has work to do to get her straggler home.

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

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  • From Axel Reichert@21:1/5 to Axel Reichert on Mon Dec 26 09:32:25 2022
    Axel Reichert <mail@axel-reichert.de> writes:

    GNU Backgammon Position ID: aLeDAxDYTvATAA
    Match ID : cIkuAAAAAAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | O O O | | O O X X | 0 points
    | O O | | O O X |
    | O | | O X |
    | | | X |
    | | | 6 |
    | |BAR| |v 1 point match
    | | | |
    | | | |
    | X | | O |
    | X X X | | O | Rolled 53
    | O X X X | | X O | 0 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 132, X 137

    Can also be rephrased as "How many blots and where?"

    No one mentioned 15/10 13/10. Over the board I played the safe 15/10
    8/5. This loses the fewest gammons, which is irrelevant in a
    1-pointer. From the candidates volunteering a direct shot the one
    blocking the opponent's 6s is best. The 10-point is not that valuable,
    but I was surprised how bad making the 3-point is. Maybe there is
    too little ammunition in the zone for a serious blitzing threat and
    giving up the slotted 8-point may prove a liability.

    Best regards

    Axel

    Rolled 53:
    1. Rollout 13/10 13/8 Eq.: +0.127
    0.564 0.134 0.011 - 0.436 0.120 0.010 CL +0.127 CF +0.127
    [0.002 0.006 0.002 - 0.002 0.006 0.004 CL 0.005 CF 0.005]
    Full cubeful rollout with variance reduction
    718 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
    Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
    Play: 0-ply cubeful [expert]
    Cube: 2-ply cubeful prune [world class]
    2. Rollout 15/10 8/5 Eq.: +0.079 (-0.049)
    0.539 0.080 0.006 - 0.461 0.066 0.003 CL +0.079 CF +0.079
    [0.002 0.006 0.002 - 0.002 0.005 0.001 CL 0.005 CF 0.005]
    Full cubeful rollout with variance reduction
    516 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
    Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
    Play: 0-ply cubeful [expert]
    Cube: 2-ply cubeful prune [world class]
    3. Rollout 15/10 13/10 Eq.: +0.050 (-0.077)
    0.525 0.102 0.004 - 0.475 0.089 0.005 CL +0.050 CF +0.050
    [0.002 0.006 0.002 - 0.002 0.005 0.001 CL 0.005 CF 0.005]
    Full cubeful rollout with variance reduction
    490 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
    Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
    Play: 0-ply cubeful [expert]
    Cube: 2-ply cubeful prune [world class]
    4. Rollout 8/3 6/3 Eq.: -0.034 (-0.161)
    0.483 0.109 0.011 - 0.517 0.118 0.005 CL -0.034 CF -0.034
    [0.002 0.006 0.004 - 0.002 0.005 0.001 CL 0.005 CF 0.005]
    Full cubeful rollout with variance reduction
    712 games, Mersenne Twister dice gen. with seed 445048384 and quasi-random dice
    Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
    Play: 0-ply cubeful [expert]
    Cube: 2-ply cubeful prune [world class]

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  • From Timothy Chow@21:1/5 to Axel Reichert on Mon Dec 26 08:13:28 2022
    On 12/26/2022 3:32 AM, Axel Reichert wrote:
    No one mentioned 15/10 13/10.

    I considered it briefly but didn't think it could possibly be better
    than 13/10 13/8.

    but I was surprised how bad making the 3-point is. Maybe there is
    too little ammunition in the zone for a serious blitzing threat and
    giving up the slotted 8-point may prove a liability.
    It's not so much the ammunition in the zone, as the fact that you're
    not going to be going all-out for a blitz when you've escaped your
    back checkers (plus gammons don't matter). The fourth point in your
    board will be helpful if O runs into the outfield and you hit her,
    but the priority is to try to prevent her from running into the
    outfield in the first place, and to make sure you have enough outfield
    coverage to hit her if she does run out.

    ---
    Tim Chow

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