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Rollout: Prime versus prime cube action

Posted By: Timothy Chow
Date: Sunday, 28 February 2010, at 8:22 p.m.

In Response To: Prime versus prime cube action (Timothy Chow)

How hard is it for Blue to jump White's prime? Fortunately I had done my homework on this question; BGOnliners with good memories may remember that I posted my results here last August. So I knew I had very good chances of leaping before I had to crack (assuming White "did nothing" in the meantime), and that the proper cube action was probably D/T here. However, I also knew that my opponent had not done his homework, and that when similar positions had come up before, he had grossly overestimated the difficulty of leaping a five-prime when not already at the edge. Therefore I had virtually no market losers in practice, so I held on the cube.

Then I rolled 6-1. Had I already turned the cube, 8/1* would be clear, but given that I was hoping to turn the cube next turn, it was tempting to just make the six-prime with 13/7 8/7. After hesitating for a while, I went ahead and hit with 8/1*. My opponent danced, and I cubed. By this time it was a big pass but he beavered!!

The rest of the story was not so interesting. I closed him out, escaped my back checker, and was bearing off for the gammon when I was forced to leave a shot. He hit from the bar, and narrowly won.

Rollouts confirmed my hunches OTB.

---

gnubg	136
tchow	102
Position ID: 2G5TAFC2bRYCIA Match ID: cAkAAAAAAAAA

• tchow doubles

Cube decision
Rollout cubeless equity		+0.563
Cubeful equities:
1.	Double, take	+0.847
2.	Double, pass	+1.000	+0.153
3.	No double	+0.642	-0.205
Proper cube action:		Double, take
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.612 0.383 0.022 - 0.388 0.062 0.002 +0.563 +0.642 Standard error 0.002 0.002 0.001 - 0.002 0.001 0.000 0.004 0.010 Player gnubg owns 2-cube 0.617 0.397 0.022 - 0.383 0.062 0.002 +1.176 +0.847 Standard error 0.002 0.002 0.001 - 0.002 0.001 0.000 0.010 0.014
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 849918597 and quasi-random dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

---

gnubg	136
tchow	102
Position ID: 2G5TAFC2bRYCIA Match ID: cIkYAAAAAAAA

• tchow moves 8/1*

#		Ply	Move	Equity
•	1	R	8/1*	+0.702
			0.567 0.406 0.024 - 0.433 0.081 0.003 +0.478 +0.702 0.001 0.001 0.001 - 0.001 0.001 0.000 0.003 0.006
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 849606282 and quasi-random dice
			Play: supremo 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	13/7 8/7	+0.605 ( -0.097)
			0.581 0.332 0.020 - 0.419 0.059 0.002 +0.453 +0.605 0.002 0.002 0.001 - 0.002 0.001 0.000 0.005 0.013
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 849606282 and quasi-random dice
			Play: supremo 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

---

gnubg	136
tchow	102
Position ID: 2G5TAFC2bRYCIA Match ID: QQkHAAAAAAAA

• tchow moves 8/1*

#		Ply	Move	Equity
•	1	R	8/1*	+0.364
			0.596 0.410 0.020 - 0.404 0.080 0.004 +0.539 +0.364 0.002 0.002 0.001 - 0.002 0.002 0.000 0.005 0.008
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 850322671 and quasi-random dice
			Play: supremo 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	13/7 8/7	+0.266 ( -0.098)
			0.581 0.335 0.020 - 0.419 0.061 0.002 +0.454 +0.266 0.002 0.002 0.001 - 0.002 0.001 0.000 0.005 0.007
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 850322671 and quasi-random dice
			Play: supremo 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

---

gnubg	137
tchow	95
Position ID: 2G5TAGBt2xQCIA Match ID: cAkAAAAAAAAA

• tchow doubles

Cube decision
Rollout cubeless equity		+0.629
Cubeful equities:
1.	Double, pass	+1.000
2.	Double, take	+1.168	+0.168
3.	No double	+0.761	-0.239
Proper cube action:		Double, pass
Rollout details
Win W g W bg Lose L g L bg Cubeless Cubeful Centered 1-cube 0.606 0.445 0.019 - 0.394 0.046 0.001 +0.629 +0.761 Standard error 0.003 0.002 0.001 - 0.003 0.001 0.000 0.006 0.010 Player gnubg owns 2-cube 0.649 0.477 0.022 - 0.351 0.054 0.002 +1.482 +1.168 Standard error 0.002 0.002 0.001 - 0.002 0.001 0.000 0.011 0.014
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 850142034 and quasi-random dice
Play: supremo 2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 16 more moves within equity 0.32
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

Messages In This Thread

• Prime versus prime cube action
  Timothy Chow -- Friday, 26 February 2010, at 2:58 a.m.
  • Prime versus prime cube action
    Martin -- Saturday, 27 February 2010, at 12:26 p.m.
    • Prime versus prime cube action
      Stick -- Saturday, 27 February 2010, at 11:46 p.m.
  • Rollout: Prime versus prime cube action
    Timothy Chow -- Sunday, 28 February 2010, at 8:22 p.m.