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52S-51S-21 – No Jacoby, No Beavers – 3-ply XG2 Rollout – Analysis

Posted By: Taper_Mike
Date: Tuesday, 23 August 2016, at 8:54 p.m.

In Response To: 52S-51S-21 (Taper_Mike)

		White is Player 2 score: 0 pip: 161 Unlimited Game pip: 160 score: 0 Blue is Player 1
XGID=-aa---E-D---dD---d-e--A-A-:0:0:1:21:0:0:0:0:10
Blue to play 21

1.	Rollout1	24/22 6/5	eq: -0.0753
	Player: Opponent: 48.02% (G:12.53% B:0.46%) 51.98% (G:12.93% B:0.55%) Conf.: ±0.0031 (-0.0784...-0.0723) - [100.0%] Duration: 4 hours 52 minutes
2.	Rollout1	22/21 13/11	eq: -0.0929 (-0.0176)
	Player: Opponent: 47.87% (G:12.60% B:0.53%) 52.13% (G:14.40% B:0.65%) Conf.: ±0.0029 (-0.0958...-0.0900) - [0.0%] Duration: 4 hours 20 minutes
3.	Rollout2	24/23 22/20	eq: -0.0997 (-0.0243)
	Player: Opponent: 47.75% (G:11.60% B:0.50%) 52.25% (G:13.89% B:0.53%) Conf.: ±0.0041 (-0.1038...-0.0956) - [0.0%] Duration: 2 hours 04 minutes
4.	Rollout3	24/21	eq: -0.1061 (-0.0308)
	Player: Opponent: 47.81% (G:11.61% B:0.54%) 52.19% (G:14.90% B:0.53%) Conf.: ±0.0058 (-0.1120...-0.1003) - [0.0%] Duration: 58 minutes 55 seconds
1 31104 Games rolled with Variance Reduction. Dice Seed: 43420919 Moves: 3-ply, cube decisions: XG Roller 2 15552 Games rolled with Variance Reduction. Dice Seed: 43420919 Moves: 3-ply, cube decisions: XG Roller 3 7776 Games rolled with Variance Reduction. Dice Seed: 43420919 Moves: 3-ply, cube decisions: XG Roller

Rollout by Taper_Mike 2016-Jul-22 eXtreme Gammon Version: 2.10.199.2658 52S-51S-21-n-tm.xgp n[E Z18 U24 V31] "<=31*15 7 n[E Z13 U21 V22] "&e

eXtreme Gammon Version: 2.10

52S-51S-21 — Unlimited Games

Bot	Seed	Equity	Nacbracs	Link
XG 2.xx 3-ply	1	–71.1	[E V27 Z31 U32] "<5	Dmitriy Obukhov
GnuBg 1.04 2-ply Trunc	793204044	–80.430	n[E Z10 U14 V17] '/0.360t	Taper_Mike
XG 2.10 3-ply, Cubes: XGR	43420919	–75.3	n[E Z18 U24 V31] "<=31*15 7	Taper_Mike
XG 2.10 XGR++ Eval	[XGR++ seed]	–80.0	n[E Z13 U21 V22] "&e	Taper_Mike

Blue would like to make an anchor in the position above. Unfortunately, after he does that, there is no easy way to play the 1. Initially, therefore, Blue should try to find a good play that does not make an anchor. I came up with Z = 22/21 13/11 when I did this. I then compared Z with the best anchoring play, E = 24/22 6/5.

Now, Timothy Chow recently revisited the second-roll position 51S-21. Famously, slotting is a reasonable play. The rollout in the XG Opening Book has $ (Slot) = 13/11 6/5 trailing behind U (Up) = 24/21 by only 9 millipoints. And at DMP, $ is the winner.

		White is Player 2 score: 0 pip: 161 Unlimited Game Jacoby Beaver pip: 167 score: 0 Blue is Player 1
XGID=-aa---E-C---dE---d-e----B-:0:0:1:21:0:0:3:0:10
51S-21   Slot (13/11 6/5) trails Up (24/21) by 9 millipoints

Knowing this, I figured slotting was reasonable in the OP after advancing my anchor. Unlike the alternative Z, anchoring creates an asset. On balance, I decided anchor-and-slot was probably a small bit better than split and down (22/21 13/11).

If I had not known about 51S-21, there is not a chance in the world that I would have considered slotting here. With that knowledge in my pocket, however, I knew that the slot was either best, or, if wrong, wrong by only a little.

Mike

Messages In This Thread

• 52S-51S-21
  Taper_Mike -- Sunday, 21 August 2016, at 8:01 p.m.
  • 52S-51S-21 – No Jacoby, No Beavers – 3-ply XG2 Rollout – Analysis
    Taper_Mike -- Tuesday, 23 August 2016, at 8:54 p.m.