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Playing 31 -- ROLLOUTS of Both Positions

Posted By: Steven E. Carey
Date: Tuesday, 21 June 2016, at 6:27 a.m.

In Response To: Playing 31 -- ROLLOUTS of Both Positions (Nack Ballard)

(I've fixed the attachments)

In my experience, these kinds of positions (make the offensive or defensive point) are extremely sensitive to the score. The difference of only one point can create an abrupt transition between strategies. It took considerable rolling out to completely make sense of this position.

		White is Player 2 score: 0 pip: 145 7 point match pip: 138 score: 0 Blue is Player 1
XGID=-b-BB-C-C--AcB---c-cbAb-A-:0:0:1:31:0:0:0:7:10
Blue to play 31

1.	Rollout1	8/5 6/5	eq: +0.431
	Player: Opponent: 59.96% (G:23.35% B:1.72%) 40.04% (G:14.58% B:0.94%) Conf.: ± 0.005 (+0.426...+0.436) - [100.0%] Duration: 43 minutes 06 seconds
2.	Rollout1	24/21 11/10	eq: +0.399 (-0.032)
	Player: Opponent: 58.43% (G:19.37% B:0.58%) 41.57% (G:8.57% B:0.41%) Conf.: ± 0.003 (+0.395...+0.402) - [0.0%] Duration: 57 minutes 43 seconds
1 15552 Games rolled with Variance Reduction. Dice Seed: 58918962 Moves: 3-ply, cube decisions: 4-ply

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

		White is Player 2 score: 0 pip: 145 7 point match pip: 138 score: 1 Blue is Player 1
XGID=-b-BB-C-C--AcB---c-cbAb-A-:0:0:1:31:1:0:0:7:10
Blue to play 31

1.	Rollout1	8/5 6/5	eq: +0.4058
	Player: Opponent: 59.97% (G:23.28% B:1.75%) 40.03% (G:14.43% B:0.87%) Conf.: ±0.0034 (+0.4024...+0.4091) - [90.9%] Duration: 1 hour 55 minutes
2.	Rollout1	24/21 11/10	eq: +0.4029 (-0.0029)
	Player: Opponent: 58.44% (G:19.31% B:0.61%) 41.56% (G:8.55% B:0.42%) Conf.: ±0.0025 (+0.4004...+0.4054) - [9.1%] Duration: 2 hours 25 minutes
1 31104 Games rolled with Variance Reduction. Dice Seed: 58918962 Moves: 3-ply, cube decisions: 4-ply

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

		White is Player 2 score: 0 pip: 145 7 point match pip: 138 score: 2 Blue is Player 1
XGID=-b-BB-C-C--AcB---c-cbAb-A-:0:0:1:31:2:0:0:7:10
Blue to play 31

1.	Rollout1	24/21 11/10	eq: +0.3175
	Player: Opponent: 58.43% (G:19.29% B:0.64%) 41.57% (G:8.45% B:0.39%) Conf.: ±0.0036 (+0.3140...+0.3211) - [100.0%] Duration: 1 hour 21 minutes
2.	Rollout1	8/5 6/5	eq: +0.2917 (-0.0258)
	Player: Opponent: 59.94% (G:23.09% B:1.87%) 40.06% (G:14.54% B:0.81%) Conf.: ±0.0043 (+0.2875...+0.2960) - [0.0%] Duration: 1 hour 03 minutes
1 15552 Games rolled with Variance Reduction. Dice Seed: 58918962 Moves: 3-ply, cube decisions: 4-ply

eXtreme Gammon Version: 2.10, MET: Kazaross XG2

As an example in this position at the beginning of a 7pt match (7A,7A), making the 5 point Is clearly correct, with a one point lead (6A-7A), the plays are equal, with a two point lead (5A,7A), the anchor is clearly correct.

As similar pattern emerges from a five or six point match. Two exceptions to this are 4A, 4A and unlimited games. There the anchor is with 2% of the 5 point. Other interesting scores are Crawford games with you opponent odd away. Then the two plays are equal with the 5 point slightly ahead.

I have an interesting visualization as a pdf, but I don't know how to attach it.

Messages In This Thread

• Playing 31
  Nack Ballard -- Tuesday, 31 May 2016, at 2:55 a.m.
  • Playing 31
    Stick -- Tuesday, 31 May 2016, at 3:31 a.m.
  • Playing 31
    sebalotek -- Tuesday, 31 May 2016, at 7:28 a.m.
  • Playing 31--quotes, as requested
    Phil Simborg -- Tuesday, 31 May 2016, at 1:31 p.m.
  • Playing 31
    Keene -- Tuesday, 31 May 2016, at 3:48 p.m.
  • Playing 31
    Casper Van der Tak -- Tuesday, 31 May 2016, at 4:53 p.m.
  • Playing 31
    ah_clem -- Tuesday, 31 May 2016, at 8:02 p.m.
  • Playing 31
    Fatboy -- Wednesday, 1 June 2016, at 2:10 a.m.
    • Playing 31
      Kevin McDonough -- Wednesday, 1 June 2016, at 2:39 a.m.
      • [Spoiler Alert] – Kevin's post includes rollout data. *NM*
        Taper_Mike -- Wednesday, 1 June 2016, at 4:10 a.m.
        • [Spoiler Alert] – Kevin's post includes rollout data.
          Fatboy -- Wednesday, 1 June 2016, at 6:02 p.m.
  • Playing 31
    Taper_Mike -- Wednesday, 1 June 2016, at 4:08 a.m.
  • Playing 31 -- VARIANT and Original Rollout
    Nack Ballard -- Saturday, 4 June 2016, at 6:46 p.m.
    • Comparing the Original Position and Variant
      Taper_Mike -- Monday, 6 June 2016, at 7:12 a.m.
  • Playing 31
    Steven E. Carey -- Tuesday, 7 June 2016, at 2:00 p.m.
    • Playing 31
      Keene -- Tuesday, 7 June 2016, at 4:51 p.m.
  • quote
    garyo -- Tuesday, 7 June 2016, at 8:40 p.m.
    • quote
      Seth -- Tuesday, 7 June 2016, at 9:15 p.m.
    • quote--Joe Sylvester
      Phil Simborg -- Wednesday, 8 June 2016, at 8:11 a.m.
      • quote--Joe Sylvester
        Seth -- Wednesday, 8 June 2016, at 11:25 a.m.
  • Playing 31 -- ROLLOUTS of Both Positions
    Nack Ballard -- Sunday, 12 June 2016, at 6:01 a.m.
    • Playing 31 -- ROLLOUTS of Both Positions
      Martin -- Sunday, 12 June 2016, at 10:21 a.m.
      • Corrected Text
        Nack Ballard -- Sunday, 12 June 2016, at 11:32 p.m.
    • Playing 31 -- ROLLOUTS of Both Positions
      Steven E. Carey -- Saturday, 18 June 2016, at 10:43 p.m.
      • Playing 31 -- ROLLOUTS of Both Positions
        sebalotek -- Monday, 20 June 2016, at 3:13 a.m.
    • Playing 31 -- ROLLOUTS of Both Positions
      Steven E. Carey -- Tuesday, 21 June 2016, at 6:27 a.m.