• No clue, no cube?

    From Axel Reichert@21:1/5 to All on Thu Dec 22 21:10:02 2022
    GNU Backgammon Position ID: 4Bw8oFSM18GAEg
    Match ID : cAlgAXAAMAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | X X X O | O | O X | 7 points
    | O | | O X |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |v 11 point match (Cube: 1)
    | | | |
    | X | | O |
    | X | | X O |
    | X X | | X O | On roll
    | O O X O O X | | X X O | 6 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 207, X 151

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  • From Timothy Chow@21:1/5 to Axel Reichert on Thu Dec 22 20:09:41 2022
    On 12/22/2022 3:10 PM, Axel Reichert wrote:
    GNU Backgammon Position ID: 4Bw8oFSM18GAEg
    Match ID : cAlgAXAAMAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | X X X O | O | O X | 7 points
    | O | | O X |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |v 11 point match (Cube: 1)
    | | | |
    | X | | O |
    | X | | X O |
    | X X | | X O | On roll
    | O O X O O X | | X X O | 6 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 207, X 151

    X looks to me to have a massive advantage here. He's over 50 pips up
    and has ten checkers in the zone. At 5a4a his gammon value is elevated.
    O's main saving grace is that she has a pretty good chance of anchoring,
    but that seems like relatively weak compensation. I would pass as O.

    Is it too good? Maybe, but if she gets a high anchor then I think she
    can take. D/P is my guess.

    ---
    Tim Chow

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  • From Stick Rice@21:1/5 to Tim Chow on Thu Dec 22 20:41:16 2022
    On Thursday, December 22, 2022 at 8:09:44 PM UTC-5, Tim Chow wrote:
    On 12/22/2022 3:10 PM, Axel Reichert wrote:
    GNU Backgammon Position ID: 4Bw8oFSM18GAEg
    Match ID : cAlgAXAAMAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | X X X O | O | O X | 7 points
    | O | | O X |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |v 11 point match (Cube: 1)
    | | | |
    | X | | O |
    | X | | X O |
    | X X | | X O | On roll
    | O O X O O X | | X X O | 6 points +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 207, X 151
    X looks to me to have a massive advantage here. He's over 50 pips up
    and has ten checkers in the zone. At 5a4a his gammon value is elevated.
    O's main saving grace is that she has a pretty good chance of anchoring,
    but that seems like relatively weak compensation. I would pass as O.

    Is it too good? Maybe, but if she gets a high anchor then I think she
    can take. D/P is my guess.

    ---
    Tim Chow

    Maybe it's what you meant but it's not entirely clear from how you said it. 5a has an elevated gammon value on a 2 cube, not a centered cube. Normally you wouldn't have to stipulate but if you're considering a position as TG or not also it needs to be
    clarified.

    Stick

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  • From Timothy Chow@21:1/5 to Stick Rice on Fri Dec 23 08:41:21 2022
    On 12/22/2022 11:41 PM, Stick Rice wrote:
    Maybe it's what you meant but it's not entirely clear from how you said it. 5a has an elevated gammon value on a 2 cube, not a centered cube. Normally you wouldn't have to stipulate but if you're considering a position as TG or not also it needs to
    be clarified.

    What you say is correct, of course, but whether a cube decision is
    TG (or not) is not particularly sensitive to the gammon value on the
    current value of the cube. For example, unless this position is
    just borderline TG, I'd expect that the answer to the "TG or not"
    question for this position would be the same at 4a4a as at 5a4a,
    even though it's surely a much bigger pass at 4a4a than at 5a4a.

    ---
    Tim Chow

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  • From Axel Reichert@21:1/5 to Axel Reichert on Sat Dec 24 14:40:56 2022
    Axel Reichert <mail@axel-reichert.de> writes:

    GNU Backgammon Position ID: 4Bw8oFSM18GAEg
    Match ID : cAlgAXAAMAAE
    +24-23-22-21-20-19------18-17-16-15-14-13-+ O: gnubg
    | X X X O | O | O X | 7 points
    | O | | O X |
    | O | | O |
    | | | |
    | | | |
    | |BAR| |v 11 point match (Cube: 1)
    | | | |
    | X | | O |
    | X | | X O |
    | X X | | X O | On roll
    | O O X O O X | | X X O | 6 points
    +-1--2--3--4--5--6-------7--8--9-10-11-12-+ X: axel
    Pip counts: O 207, X 151

    Big double, big pass. Far from too good. Over the board I kept the cube,
    my judgement was impaired by the many blots (4 each): "Too much play in
    this game I thought" and missed the fact that Position, Race And Threats
    all point to a double and, with 3:0 criteria, to a pass as well.

    Cube analysis
    Rollout cubeless equity +0.693 (Money: +0.673)

    Cubeful equities:
    1. Double, pass +1.000
    2. Double, take +1.290 (+0.290)
    3. No double +0.875 (-0.125)
    Proper cube action: Double, pass

    Rollout details:
    Centered 1-cube:
    0.636 0.398 0.069 - 0.364 0.065 0.003 CL +0.693 CF +0.875
    [0.000 0.001 0.000 - 0.000 0.000 0.000 CL 0.002 CF 0.002]
    Player gnubg owns 2-cube:
    0.637 0.397 0.068 - 0.363 0.065 0.003 CL +1.666 CF +1.290
    [0.001 0.001 0.001 - 0.001 0.000 0.000 CL 0.005 CF 0.005]
    Truncated cubeful rollout (depth 6) with variance reduction
    1474 games, Mersenne Twister dice gen. with seed 445148145 and quasi-random dice
    Stop when std.errs. are small enough: limit 0.0050 (min. 36 games)
    Play: world class 2-ply cubeful prune [world class]
    keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
    Skip pruning for 1-ply moves.
    Cube: 2-ply cubeful prune [world class]
    Different evaluations after 2 plies:
    Play: 1-ply cubeful
    keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
    Cube: 2-ply cubeful prune [world class]
    Output generated Sat Dec 24 14:19:59 2022
    by GNU Backgammon 1.06.002 Nov 19 2020 (Text Export version 1.114)

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