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Rollout: Which doublets are hardest to play?

Posted By: Timothy Chow
Date: Tuesday, 4 May 2010, at 11:46 p.m.

In Response To: Which doublets are hardest to play? (Timothy Chow)

Second position first: No tricks here; 8/4*(2) 13/9(2) is the right play. OTB I played 8/4*(2) 6/2(2) which is sometimes the right way to blitz but here just overextends Blue's position.

The first position is more subtle. Daniel Murphy gave a good analysis. The key feature of the position is Blue's trapped checkers. One option for Blue is the quieter plan of trying to escape his back checkers or anchor them when the dice allow it, and to counterprime otherwise. Blue's other plan is to build the board immediately with 8/4(2) 6/2(2) and hope to hit White soon. OTB the latter plan did not occur to me and I played 13/9(2) 13/5. According to the rollout, 8/4(2) 6/2(2) is better.

I'm still not sure I grasp the finer points of the hitting plan, because changing the position slightly can alter GNU's opinion. For example, say we move a checker from White's midpoint to White's 8 point, giving White a four-prime. Does this make the quiet plan even more hopeless because White's prime is even stronger? Or does it make the hitting plan even more hopeless because White has cleaned up the blot? I should roll it out but GNU 4-ply slightly prefers 13/9(3) 10/6 in this variant position.

gnubg	159
tchow	155
Position ID: sFvwAQyw58QBMA Match ID: cAkSABAAAAAA

#		Ply	Move	Equity
•	1	R	8/4(2) 6/2(2)	-0.370
			0.404 0.120 0.004 - 0.596 0.158 0.007 -0.233 -0.370 0.001 0.002 0.001 - 0.001 0.002 0.000 0.004 0.012
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 855058577 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	13/9(3) 8/4	-0.401 ( -0.031)
			0.397 0.119 0.005 - 0.603 0.168 0.009 -0.260 -0.401 0.002 0.002 0.000 - 0.002 0.002 0.001 0.005 0.013
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 855058577 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]
	3	R	13/5 13/9(2)	-0.421 ( -0.051)
			0.388 0.118 0.005 - 0.612 0.161 0.007 -0.270 -0.421 0.002 0.002 0.001 - 0.002 0.002 0.000 0.005 0.011
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 855058577 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]
	4	R	13/9(3) 10/6	-0.425 ( -0.055)
			0.394 0.108 0.004 - 0.606 0.160 0.006 -0.267 -0.425 0.002 0.001 0.000 - 0.002 0.002 0.000 0.004 0.011
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 855058577 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	119
tchow	137
Position ID: szmDAQqw58EcAA Match ID: UQkSADAAKAAA

#		Ply	Move	Equity
•	1	R	13/9(2) 8/4*(2)	+0.958
			0.737 0.184 0.005 - 0.263 0.045 0.001 +0.619 +0.958 0.001 0.002 0.000 - 0.001 0.001 0.000 0.002 0.005
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 855392768 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	8/4*(2) 6/2(2)	+0.862 ( -0.095)
			0.700 0.228 0.008 - 0.300 0.076 0.002 +0.559 +0.862 0.001 0.002 0.000 - 0.001 0.001 0.000 0.003 0.006
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 855392768 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

• Which doublets are hardest to play?
  Timothy Chow -- Monday, 3 May 2010, at 11:51 p.m.
  • Which doublets are hardest to play?
    Leonardo Jerkovic -- Tuesday, 4 May 2010, at 12:03 a.m.
  • Which doublets are hardest to play?
    Neil Robins -- Tuesday, 4 May 2010, at 8:28 a.m.
  • Which doublets are hardest to play?
    Havard Raddum -- Tuesday, 4 May 2010, at 8:52 a.m.
  • Which doublets are hardest to play?
    Chuck Bower -- Tuesday, 4 May 2010, at 7:19 p.m.
  • Which doublets are hardest to play?
    Daniel Murphy -- Tuesday, 4 May 2010, at 8:36 p.m.
    • Which doublets are hardest to play?
      christian munk-christensen -- Wednesday, 5 May 2010, at 7:35 a.m.
      • Which doublets are hardest to play?
        Daniel Murphy -- Wednesday, 5 May 2010, at 7:34 p.m.
  • Rollout: Which doublets are hardest to play?
    Timothy Chow -- Tuesday, 4 May 2010, at 11:46 p.m.
    • Rollout: Which doublets are hardest to play?
      Daniel Murphy -- Wednesday, 5 May 2010, at 12:06 a.m.
      • Rollout: Which doublets are hardest to play?
        Casper van der Tak -- Wednesday, 5 May 2010, at 7:33 a.m.