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Advanced Backgammon part 22A

Posted By: Matt Cohn-Geier
Date: Tuesday, 17 March 2009, at 10:45 p.m.

In Response To: Advanced Backgammon part 22A (Matt Cohn-Geier)

Position 211:

Neil is basically right here, this one is quite close but paying later is slightly better. Blue may be able to hold on for another roll and get White to break, whereas if he gets hit now it may be a hit and cover.

Move number 5: Blue to play 45

White	88
Blue	71
Position ID: u1kVYAA39wIGAA Match ID: QQkWAAAAAAAA

• Blue moves 13/4

#		Ply	Move	Equity
	1	R	6/1 5/1	+0.2087
			0.6633 0.0083 0.0001 - 0.3367 0.0080 0.0001 +0.3268 +0.2087 0.0001 0.0001 0.0000 - 0.0001 0.0000 0.0000 0.0002 0.0002
			Full cubeful rollout with var.redn.
			90895 games, Mersenne Twister dice gen. with seed 806413303 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
•	2	R	13/4	+0.2030 ( -0.0057)
			0.6545 0.0473 0.0020 - 0.3455 0.0123 0.0002 +0.3458 +0.2030 0.0004 0.0008 0.0002 - 0.0004 0.0003 0.0000 0.0010 0.0015
			Full cubeful rollout with var.redn.
			2904 games, Mersenne Twister dice gen. with seed 806413303 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Position 212:

Historically, Robertie says, players in the 70 made the ingenious plays of paying off now and winning big. Except it's a really bad time to pay off, when White has a 5 point prime and no blots. Breaking the bar is somewhat better but there's really no upside.

Move number 5: Blue to play 36

White	139
Blue	94
Position ID: 2LbBAQO22Q4GAA Match ID: QYkZAAAAAAAA

• Blue moves 8/2 4/1

#		Ply	Move	Equity
•	1	R	8/2 4/1	+0.3872
			0.7275 0.0497 0.0009 - 0.2725 0.0322 0.0008 +0.4726 +0.3872 0.0015 0.0016 0.0004 - 0.0015 0.0011 0.0002 0.0035 0.0051
			Full cubeful rollout with var.redn.
			655 games, Mersenne Twister dice gen. with seed 812554984 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	7/4 7/1	+0.2698 ( -0.1174)
			0.6766 0.0600 0.0008 - 0.3234 0.0360 0.0009 +0.3771 +0.2698 0.0016 0.0015 0.0002 - 0.0016 0.0014 0.0001 0.0036 0.0055
			Full cubeful rollout with var.redn.
			655 games, Mersenne Twister dice gen. with seed 812554984 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	3	R	13/10 13/7	+0.2283 ( -0.1589)
			0.6681 0.0452 0.0003 - 0.3319 0.0220 0.0004 +0.3593 +0.2283 0.0015 0.0014 0.0001 - 0.0015 0.0008 0.0001 0.0032 0.0050
			Full cubeful rollout with var.redn.
			654 games, Mersenne Twister dice gen. with seed 812554984 and quasi-random dice
			Play: 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Position 213:

Clear double, clear take. White can take because the 11 point can be tough to clear and Blue is stripped in the outfield and has already started dumping checkers. Put three spares back in the outfield (with the same racing lead) and it's a pretty clear pass.

Move number 3: Blue on roll, cube decision?

White	133
Blue	112
Position ID: zM6FAQMsb2MGAA Match ID: cAkAAAAAAAAA

• Blue doubles

Cube decision
Rollout cubeless equity		+0.5088
Cubeful equities:
1.	Double, take	+0.9039
2.	Double, pass	+1.0000	+0.0961
3.	No double	+0.8616	-0.0423
Proper cube action:		Double, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.7533 0.0196 0.0004 - 0.2467 0.0171 0.0006 +0.5088 +0.8616 Standard error 0.0010 0.0007 0.0001 - 0.0010 0.0008 0.0001 0.0023 0.0053 Player White owns 2-cube 0.7580 0.0181 0.0000 - 0.2420 0.0157 0.0006 +1.0354 +0.9039 Standard error 0.0011 0.0008 0.0051 - 0.0011 0.0008 0.0001 0.0050 0.0064
Full cubeful rollout with var.redn.
1092 games, Mersenne Twister dice gen. with seed 812210319 and quasi-random dice
Play: 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 12 more moves within equity 0.2
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

Messages In This Thread

• Advanced Backgammon part 22A
  Matt Cohn-Geier -- Sunday, 15 March 2009, at 8:52 a.m.
  • Advanced Backgammon part 22A
    Chuck Bower -- Sunday, 15 March 2009, at 3:14 p.m.
  • Advanced Backgammon part 22A
    Peter G. -- Sunday, 15 March 2009, at 3:24 p.m.
  • Advanced Backgammon part 22A
    neilkaz -- Sunday, 15 March 2009, at 3:54 p.m.
  • Advanced Backgammon part 22A
    Rich Munitz -- Sunday, 15 March 2009, at 7:45 p.m.
    • Advanced Backgammon part 22A
      Rich Munitz -- Sunday, 15 March 2009, at 7:47 p.m.
  • Robertie's picks
    Matt Cohn-Geier -- Sunday, 15 March 2009, at 11:41 p.m.
    • Robertie's picks
      neilkaz -- Sunday, 15 March 2009, at 11:46 p.m.
  • Advanced Backgammon part 22A
    Stick -- Monday, 16 March 2009, at 12:03 a.m.
  • Advanced Backgammon part 22A
    Matt Cohn-Geier -- Tuesday, 17 March 2009, at 10:45 p.m.
    • Advanced Backgammon part 22A
      Rich Munitz -- Tuesday, 17 March 2009, at 11:24 p.m.
      • Advanced Backgammon part 22A
        Matt Cohn-Geier -- Tuesday, 17 March 2009, at 11:44 p.m.