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3-away 7-away cube action

Posted By: Chuck Bower
Date: Monday, 26 October 2009, at 9:40 p.m.

In Response To: 3-away 7-away cube action (Daniel Murphy)

(From memory:) Pass for 15.5%. Take and win for 35%. Take and lose simple for 9%. Take and lose G for 0%.

Prorate the takes (about 4::5 looks not far off) for 5% MWC. Risk 10.5% out of 30% for a worthless cube takepoint of 10.5/30 = 21/60 = 7/20 = 35%.

If the cube comes back to 4, Blue passes for 65%; takes and wins for the match (100%); takes and loses simple for 50%; takes and loses gammon for the match (0%). Prorate the take+lose at 25% gammon fraction (WAG) so taking and losing is worth 37.5%. Risk 65 - 37.5 = 27.5 out of a possible 100 - 37.5 = 62.5 means the takepoint at 4 will be 27.5/62.5 = 55/125 = 11/25 or 44%.

So now White's perfect cube efficiency takepoint is 56% of 35% ~ 19.5%. With realistic cube we now (at least think we) know that the takepoint is bounded below by 19.5% and above by 35%. But how much cube efficiency is there?

I used to think it was more than the typical 70% at a score like this until a position a month or so ago squelched that thought. When cube owner is going to rewind on just a sneeze then maybe cube efficiency is considerably worse than typical.... (Recall White will risk between 5% and 9% to gain somewhere between 15% and 25%.)

If cube efficiency is 50% for White then s/he needs about 27% or so to take here. I do think White has that.

Blue might have a cube here, particularly if the cube efficiency is worse than I assumed. I'd probably still be afraid to ship it, though.

N+T.

Messages In This Thread

• 3-away 7-away cube action
  Daniel Murphy -- Sunday, 25 October 2009, at 1:52 a.m.
  • 3-away 7-away cube action
    Rich Munitz -- Sunday, 25 October 2009, at 4:17 a.m.
  • 3-away 7-away cube action
    Peter G. -- Sunday, 25 October 2009, at 10:01 a.m.
  • 3-away 7-away cube action
    jdg -- Sunday, 25 October 2009, at 3:09 p.m.
  • 3-away 7-away cube action
    David -- Monday, 26 October 2009, at 1:50 a.m.
  • 3-away 7-away cube action
    rory -- Monday, 26 October 2009, at 4:04 a.m.
  • 3-away 7-away cube action
    Chuck Bower -- Monday, 26 October 2009, at 9:40 p.m.
    • 3-away 7-away cube action
      Chuck Bower -- Tuesday, 27 October 2009, at 12:10 a.m.
  • 3-away 7-away cube action
    Keene -- Tuesday, 27 October 2009, at 3:12 p.m.
  • 3-away 7-away cube action
    neilkaz -- Tuesday, 27 October 2009, at 4:00 p.m.
  • 3-away 7-away cube - RO
    Daniel Murphy -- Tuesday, 27 October 2009, at 6:12 p.m.
    • 3-away 7-away cube - RO
      Christian Munk-Christensen -- Tuesday, 27 October 2009, at 6:57 p.m.
    • 3-away 7-away cube - RO
      Rich Munitz -- Tuesday, 27 October 2009, at 7:27 p.m.
      • What is "Stick's Rule"? *NM*
        Timothy Chow -- Tuesday, 27 October 2009, at 9:07 p.m.
      • 3-away 7-away cube - RO
        Christian Munk-Christensen -- Tuesday, 27 October 2009, at 9:30 p.m.
        • 3-away 7-away cube action
          Chuck Bower -- Wednesday, 28 October 2009, at 12:30 a.m.
          • 3-away 7-away cube action
            Rich Munitz -- Wednesday, 28 October 2009, at 4:53 a.m.
            • 3-away 7-away cube action
              Christian Munk-Christensen -- Wednesday, 28 October 2009, at 11:25 a.m.
      • 3-away 7-away cube - RO
        Matt Cohn-Geier -- Wednesday, 28 October 2009, at 9:58 a.m.
        • 3-away 7-away cube - RO
          Rich Munitz -- Wednesday, 28 October 2009, at 1:28 p.m.
    • 3-away 7-away cube - RO
      rew -- Wednesday, 28 October 2009, at 9:24 a.m.
      • 3-away 7-away cube - RO
        rew -- Wednesday, 28 October 2009, at 2:12 p.m.
    • XG RO agrees
      neilkaz -- Thursday, 29 October 2009, at 3:57 p.m.