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  • Tried to follow O'Hagan

    From [email protected]@21:1/5 to All on Sat Feb 5 02:38:17 2022
    Tried to follow O'Hagan's law
    But the play just came out wrong
    So I'll have to refer to O'Hagan
    In a song.

    XGID=---BCCB-BAb-aB-----bbcbba-:0:0:1:00:4:3:3:0:X:Daniel O:eXtremeGammon
    10

    Score is X:4 O:3. Unlimited Game, Jacoby Beaver
    +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X | | O O O O O O |
    | X | | O O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X |
    | O X | | X X X X |
    | O O X X | | X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 96 O: 88 X-O: 4-3
    Cube: 1
    X on roll, cube action

    In the above position, the 11 hits are very strong and missing leads to approximate equality. My instinct was that it looks like a hold, but this seemed counter to O'Hagan's principle. I don't have the patience
    for a rollout but my cube does seem like a major blunder.
    I'm really not sure that O'Hagan's law is all that helpful.
    It seems like more of a tool for justifying a cube after the fact, than reaching a good decision OTB.

    Paul


    Analyzed in XG Roller+
    Player Winning Chances: 57.41% (G:4.00% B:0.08%)
    Opponent Winning Chances: 42.59% (G:1.26% B:0.03%)

    Cubeless Equities: No Double=+0.176, Double=+0.339

    Cubeful Equities:
    No double: +0.220
    Double/Take: +0.065 (-0.155)
    Double/Pass: +1.000 (+0.780)

    Best Cube action: No double / Take
    Percentage of wrong pass needed to make the double decision right: 14.2%

    eXtreme Gammon Version: 2.10

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Timothy Chow@21:1/5 to [email protected] on Sat Feb 5 09:54:36 2022
    On 2/5/2022 5:38 AM, [email protected] wrote:
    In the above position, the 11 hits are very strong and missing leads to approximate equality.

    I can't say for sure what the intent of O'Hagan's law is,
    but I think that after you're mediocre rolls you're supposed
    to have a slight but definite advantage, as opposed to being
    equal or slightly worse. Certainly in this sort of position,
    where you're close to disengaging but have a powerful direct
    shot, I tend to use the positions in Trice's chapter on
    "End-contact positions" as a guide. If the race is even and
    hitting totally locks up the game, and there's minimal contact
    otherwise, then the double is clear. Here there are caveats
    on all three points---you're behind in the race, hitting does
    not necessarily lock up the game because you have only a
    four-point board, and there's a bit of contact even if you
    miss. Of these I think being behind in the race is the most
    significant. If it turns into a race, your opponent will be
    delighted that you gave up cube access.

    ---
    Tim Chow

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Stick Rice@21:1/5 to [email protected] on Sat Feb 5 18:36:33 2022
    On Saturday, February 5, 2022 at 5:38:19 AM UTC-5, [email protected] wrote:
    Tried to follow O'Hagan's law
    But the play just came out wrong
    So I'll have to refer to O'Hagan
    In a song.

    XGID=---BCCB-BAb-aB-----bbcbba-:0:0:1:00:4:3:3:0:X:Daniel O:eXtremeGammon
    10

    Score is X:4 O:3. Unlimited Game, Jacoby Beaver +13-14-15-16-17-18------19-20-21-22-23-24-+
    | X | | O O O O O O |
    | X | | O O O O O |
    | | | O |
    | | | |
    | | | |
    | |BAR| |
    | | | |
    | | | |
    | | | X X |
    | O X | | X X X X |
    | O O X X | | X X X X |
    +12-11-10--9--8--7-------6--5--4--3--2--1-+
    Pip count X: 96 O: 88 X-O: 4-3
    Cube: 1
    X on roll, cube action

    In the above position, the 11 hits are very strong and missing leads to approximate equality. My instinct was that it looks like a hold, but this seemed counter to O'Hagan's principle. I don't have the patience
    for a rollout but my cube does seem like a major blunder.
    I'm really not sure that O'Hagan's law is all that helpful.
    It seems like more of a tool for justifying a cube after the fact, than reaching a good decision OTB.

    Paul


    Analyzed in XG Roller+
    Player Winning Chances: 57.41% (G:4.00% B:0.08%)
    Opponent Winning Chances: 42.59% (G:1.26% B:0.03%)

    Cubeless Equities: No Double=+0.176, Double=+0.339

    Cubeful Equities:
    No double: +0.220
    Double/Take: +0.065 (-0.155)
    Double/Pass: +1.000 (+0.780)

    Best Cube action: No double / Take
    Percentage of wrong pass needed to make the double decision right: 14.2%

    eXtreme Gammon Version: 2.10

    It is definitely useful for reaching the correct decision OtB. Like most bg maxims, the end user needs to be familiar with the exact rule and application to successfully use it OtB. For eg in your eg you said that the 11 hits are pretty strong but
    what does that mean in relation to trying to apply the rule? Do you lose your market every time you hit? If not, how often? You also said missing would lead to 'approximate equality'. O'Hagan's Law states loosely that you're 'doing ok' on the rest of
    the rolls. While this is a bit waffly, it definitely does not mean we're negative equity in general on a bunch of rolls. (as we are here)

    Stick

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)