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xxP-43Z-32 — Summary and Analysis

Posted By: Taper_Mike
Date: Wednesday, 22 February 2012, at 9:25 p.m.

In Response To: 53P-43Z-32 — Only 96% confidence after 80k (Taper_Mike)

The positions in this thread all have Blue making an inner board point with his opening roll, and his opponent splitting to the 4pt or 5pt on his turn. On the third roll, Blue faces a choice of hitting once and bringing a builder down, or hitting twice and leaving a blot on the 1pt. Owning the 4pt or 5pt gives Blue better priming chances than owning the 2pt or 3pt. When Blue owns the 4pt or 5pt, it is better to hit once.

42P-43S-41 – [H X23 K25] "<=5 Position ID: 4HPiASGYZ/ABMA Match ID: cIkQAAAAAAAA

31P-43Z-32 – [H X24 K70] "<=5 Position ID: 4HPhASKwZ/ABMA Match ID: cAkNAAAAAAAA

Owning the 2pt gives Blue much a weaker priming game, so hitting twice dominates hitting once and building. The tipping point comes when Blue owns the 3pt. By the Ballard/Weaver Error Scale, it’s your choice. Hitting once is tied with hitting twice.

64P-43Z-32 – [K X21 H28] "<=5 Position ID: 4HPhASKGZ/ABMA Match ID: cAkNAAAAAAAA

53P-43Z-32 – [K H3.7 X21.0] "<=103*20 Position ID: 4HPhASKMZ/ABMA Match ID: cAkNAAAAAAAA

There is a common backgammon maxim that is not supported by these results. That rule says to hit twice after your opponent makes a minor split to the 2pt or 3pt, and to hit just once when he makes a major split to the 4pt or 5pt. In the examples here, the opponent has made a major split, yet sometimes it is correct to hit twice. 31P-43S-32 – [H X24 K70] "<=5 – (aka 31P-43Z-32) 42P-43S-41 – [H X23 K25] "<=5 53P-43Z-32 – [K H3.7 X21.0] "<=103*20 64P-43Z-32 – [K X21 H28] "<=5 42P-32S-32 – [K H33 X56] "<=5 – (aka 42P-32Z-32) Key: 32H = Hit (13/10, 6/4*), 32K = Kill (6/4*/1*), 32X = Hit and split (24/21, 6/4*) 41H = Hit (13/9, –6/5*), 41K = Kill (6/5*/1*), 41X = Hit and split (24/20, 6/5*) Nacbracs explanation Mike

Messages In This Thread

• 53P-43Z-32 — Only 96% confidence after 80k
  Taper_Mike -- Monday, 20 February 2012, at 3:00 a.m.
  • 53P-43Z-32 — Only 96% confidence after 80k
    Daniel Murphy -- Monday, 20 February 2012, at 3:23 a.m.
  • 53P-43Z-32 for money and at DMP
    Dmitriy Obukhov -- Monday, 20 February 2012, at 7:31 a.m.
    • 53P-43Z-32 at DMP
      Taper_Mike -- Monday, 20 February 2012, at 9:07 p.m.
  • 53P-43Z-32 — Rollouts for Money and DMP
    Taper_Mike -- Tuesday, 21 February 2012, at 5:52 a.m.
    • 53P-43Z-32 — Rollouts for Money and DMP
      Daniel Murphy -- Tuesday, 21 February 2012, at 6:47 a.m.
      • 53P-43Z-32 versus 64P-43Z-32
        Taper_Mike -- Tuesday, 21 February 2012, at 8:42 a.m.
        • 53P-43Z-32 versus 64P-43Z-32
          Daniel Murphy -- Tuesday, 21 February 2012, at 8:51 a.m.
          • 53P-43Z-32 versus 64P-43Z-32
            Casper van der Tak -- Tuesday, 21 February 2012, at 9:15 a.m.
  • 64P-43Z-32 — Rollout
    Taper_Mike -- Wednesday, 22 February 2012, at 6:19 a.m.
  • 31P-43Z-32 — Rollout — (aka 31P-43S-32)
    Taper_Mike -- Wednesday, 22 February 2012, at 6:27 a.m.
  • 42P-43S-41 — Rollout
    Taper_Mike -- Wednesday, 22 February 2012, at 6:32 a.m.
  • 42P-32S-32 — Rollout — (aka 42P-32Z-32)
    Taper_Mike -- Wednesday, 22 February 2012, at 8:38 a.m.
  • xxP-43Z-32 — Summary and Analysis
    Taper_Mike -- Wednesday, 22 February 2012, at 9:25 p.m.
    • xxP-43Z-32 — Summary and Analysis
      Casper van der Tak -- Wednesday, 22 February 2012, at 10:09 p.m.
    • xxP-43Z-32 — Summary and Analysis
      Nack Ballard -- Friday, 24 February 2012, at 12:03 p.m.