BGonline.org Forums

RO dissapeared

Posted By: John O'Hagan
Date: Monday, 3 June 2013, at 4:28 p.m.

In Response To: 42 for White (John O'Hagan)

What's the gammon value ATS? It's actually right around the normal 50% since single game swings take the leader from 100% to 67% MWC while a gammon loss ties the score with 50% MWC. So the gammon value is only slightly over 50%. So if the ratio of extra wins/extra gammon losses after 18/16x-12 is slightly over 1/2, then hitting's correct, right? That would be true if there was no threat of losing a bg. But hitting here leaves 6 blots around the board - a very bgish thing to do. Not a smart thing to do ATS when the 2-cube bg value is over 200% (~67/33). Notice that 23 of Black's 27 entering numbers hit somewhere so the dreaded hit/dance sequence occurs nearly 1/6 of the time.

So the standard for the hitting play to be correct is that it must increase your winning chances by half your extra gammon-losing chances and 200% of your extra backgammon-losing chances.

The RO dissapeared but it showed that the extra wins were not quite enough to make up for the extra g & bg losses. The RO numbers were very similar to the ++ eval which is shown below. Quietly making your own 5-point is slightly better ATS.

	is Player 2 score: 7 pip: 110 13 point match pip: 134 score: 11 is Player 1
XGID=---BB-CABAA---cbabBc-bb-A-:1:1:1:42:11:7:0:13:10
to play 42

1.	XG Roller++	9/5 7/5	eq: -0.524
	Player: Opponent: 29.17% (G:3.30% B:0.06%) 70.83% (G:9.95% B:0.19%)
2.	XG Roller++	18/16* 16/12	eq: -0.529 (-0.005)
	Player: Opponent: 43.45% (G:13.61% B:0.66%) 56.55% (G:26.36% B:4.29%)

eXtreme Gammon Version: 2.00, MET: Kazaross XG2

Messages In This Thread

• 42 for White
  John O'Hagan -- Sunday, 2 June 2013, at 2:40 p.m.
  • 42 for White
    KenB -- Sunday, 2 June 2013, at 4:16 p.m.
  • 42 for White
    ah_clem -- Monday, 3 June 2013, at 3:01 p.m.
    • 42 for White
      Michael Sullivan -- Monday, 3 June 2013, at 4:26 p.m.
  • RO dissapeared
    John O'Hagan -- Monday, 3 June 2013, at 4:28 p.m.
  • Rollouts under this post
    KenB -- Monday, 3 June 2013, at 6:22 p.m.
    • Original position
      KenB -- Monday, 3 June 2013, at 6:25 p.m.
    • Gammon Save
      KenB -- Monday, 3 June 2013, at 6:27 p.m.
      • Wrong position
        Philippe Michel -- Tuesday, 4 June 2013, at 7:15 p.m.
        • Wrong position - is ok
          KenB -- Tuesday, 4 June 2013, at 8:24 p.m.
    • -13 -13
      KenB -- Monday, 3 June 2013, at 6:29 p.m.
    • DMP
      KenB -- Monday, 3 June 2013, at 6:31 p.m.
    • Thx 4 the RO's Ken *NM*
      John O'Hagan -- Tuesday, 4 June 2013, at 12:25 a.m.
      • Thx 4 the RO's Ken
        Daniel Murphy -- Tuesday, 4 June 2013, at 1:32 a.m.
        • Thx 4 the RO's Ken
          John O'Hagan -- Tuesday, 4 June 2013, at 2:29 p.m.
          • Thx 4 the RO's Ken
            Dmitriy Obukhov -- Tuesday, 4 June 2013, at 2:57 p.m.
    • and at 2-away 4-away
      Daniel Murphy -- Wednesday, 5 June 2013, at 4:30 a.m.