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Correct to double and correct to beaver

Posted By: Timothy Chow
Date: Friday, 31 July 2009, at 1:05 a.m.

In Robertie's Advanced Backgammon, there is a contrived position where, assuming the Jacoby rule, it is correct for White to double and correct for Black to beaver. I don't have the book with me, but the position was something like this: White has 14 checkers on his ace point; Black has three checkers on each of the remaining points in White's home table; White's 15th checker is at the edge of Black's 5-prime.

A crucial part of the analysis is the assumption that if White fails to leap the prime immediately and Black (re)doubles, then White must drop. The question I have is, is this really a drop?

Rolling the position out a few times by hand seemed to confirm my suspicion that there is a good chance that Black will roll double-4's or something similarly awkward early on. It then is not trivial to rebuild the 6-prime, and White has decent chances of jokering over Black's blockade and winning a gammon.

Blindly rolling out the position with gnubg suggests that the position is a huge take for White, but I don't trust gnubg's ability to roll the prime correctly over such a long distance.

Has anyone written special-purpose routines to roll primes? It seems that a relatively straightforward dynamic program should be able to play Black's side nearly optimally.

Messages In This Thread

• Correct to double and correct to beaver
  Timothy Chow -- Friday, 31 July 2009, at 1:05 a.m.
  • Correct to double and correct to beaver
    Petter Bengtsson -- Friday, 31 July 2009, at 1:25 a.m.
    • Correct to double and correct to beaver
      Rich Munitz -- Friday, 31 July 2009, at 4:05 a.m.
      • Jacoby Paradox
        Petter Bengtsson -- Friday, 31 July 2009, at 4:26 a.m.
        • My opinion of the Jacoby Rule is well known
          neilkaz -- Saturday, 1 August 2009, at 12:59 a.m.
      • Correct to double and correct to beaver
        Timothy Chow -- Saturday, 1 August 2009, at 12:18 a.m.
        • Correct to double and correct to beaver
          Casper van der Tak -- Thursday, 10 June 2010, at 5:19 a.m.
          • Correct to double and correct to beaver
            Casper van der Tak -- Thursday, 10 June 2010, at 8:34 a.m.
            • Correct to double and correct to beaver
              Petter Bengtsson -- Thursday, 10 June 2010, at 8:52 a.m.
              • Correct to double and correct to beaver
                Casper van der Tak -- Thursday, 10 June 2010, at 9:14 a.m.
              • Correct to double and correct to beaver
                Matt Cohn-Geier -- Thursday, 10 June 2010, at 1:09 p.m.
            • Correct to double and correct to beaver
              Timothy Chow -- Thursday, 10 June 2010, at 3:14 p.m.
              • Correct to double and correct to beaver
                Casper van der Tak -- Thursday, 10 June 2010, at 3:31 p.m.
                • Correct to double and correct to beaver
                  Rich Munitz -- Thursday, 10 June 2010, at 5:30 p.m.
              • Correct to double and correct to beaver
                Daniel Murphy -- Thursday, 10 June 2010, at 3:47 p.m.
                • Correct to double and correct to beaver
                  Timothy Chow -- Thursday, 10 June 2010, at 10:03 p.m.
                  • Correct to double and correct to beaver
                    Casper van der Tak -- Thursday, 10 June 2010, at 10:12 p.m.
                    • Correct to double and correct to beaver
                      Timothy Chow -- Thursday, 10 June 2010, at 11:17 p.m.
                      • Correct to double and correct to beaver
                        Casper van der Tak -- Friday, 11 June 2010, at 11:52 p.m.
      • Kauder paradox example from real game
        eXtreme Gammon -- Monday, 14 June 2010, at 6:16 p.m.
        • Kauder paradox example from real game
          Dorn Bishop -- Monday, 14 June 2010, at 8:52 p.m.
        • Kauder paradox example from real game
          Timothy Chow -- Monday, 14 June 2010, at 9:09 p.m.
        • Kauder paradox example from real game
          Daniel Murphy -- Monday, 14 June 2010, at 9:26 p.m.
          • Kauder paradox example from real game
            Petter Bengtsson -- Monday, 14 June 2010, at 9:31 p.m.
  • Correct to double and correct to beaver
    Daniel Murphy -- Thursday, 10 June 2010, at 1:02 a.m.
    • Correct to double and correct to beaver
      Seth -- Monday, 14 June 2010, at 4:42 p.m.
      • Correct to double and correct to beaver
        Matt Cohn-Geier -- Monday, 14 June 2010, at 4:58 p.m.
        • Correct to double and correct to beaver
          Casper van der Tak -- Monday, 14 June 2010, at 5:24 p.m.
      • Correct to double and correct to beaver
        Daniel Murphy -- Monday, 14 June 2010, at 7:58 p.m.
        • Correct to double and correct to beaver
          Seth -- Monday, 14 June 2010, at 10:57 p.m.
          • Correct to double and correct to beaver
            Daniel Murphy -- Monday, 14 June 2010, at 11:30 p.m.
            • Correct to double and correct to beaver
              Seth -- Tuesday, 15 June 2010, at 2:48 a.m.
              • Correct to double and correct to beaver
                Daniel Murphy -- Tuesday, 15 June 2010, at 2:52 a.m.
                • Correct to double and correct to beaver
                  Stick -- Tuesday, 15 June 2010, at 3:04 a.m.
                  • Correct to double and correct to beaver
                    Daniel Murphy -- Tuesday, 15 June 2010, at 4:01 a.m.
          • Correct to double and correct to beaver
            Daniel Murphy -- Tuesday, 15 June 2010, at 1:19 a.m.
            • Correct to -- correction
              Daniel Murphy -- Tuesday, 15 June 2010, at 2:25 a.m.
          • Correct to double and correct to beaver
            Casper van der Tak -- Tuesday, 15 June 2010, at 3:41 a.m.