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Rollout

Posted By: Matt Cohn-Geier
Date: Thursday, 12 July 2007, at 8:47 p.m.

In Response To: Food for thought (Matt Cohn-Geier)

Luckily, lunch today isn't BK.

When I first looked at this, I thought the safe play was probably right. So then I asked: how do we bring this position home? Well, next roll we probably bring a checker or two down from the midpoint, since we're not leaving the 20 point anchor. But if we're going to leave an outfield blot next roll, shouldn't we just give them to him now before White starts making points behind us and we have him outboarded 3:1?

Of the not-so-safe plays I was partial to 13/7, 8/5, since it seems to give the best distribution, and making a solid 4 prime will be better than a broken 4 prime, both for coming in against the anchor and in the event that White runs. However I don't have any particular objection to 13/4. 13/7 9/6 didn't look right, but I imagine it's similar to the other plays that leave two blots. Between 13/4 and 13/7 8/5, it's TCTC.

The captain thought along the same lines as me and we ended up going with 13/7 8/5. The next sequence was 54: 22/18*/13, 54: B/20 13/9, 54: 22/13, and we ended up with a decent one-way 5 point holding game as White cleared his bar prematurely. We eventually lost on 4 cubes.

So what's going on here? Well, leaving two (direct) blots seems to be a lot worse than leaving one. The double hitters are quite bad, even though there's only 4 of them. Still, this position is tough to bring around with no points in the outfield. White has problems too though, and he may have to break his midpoint or leave blots in his home board, when it will be safer to play loosely.

All in all, I guess we overplayed the position.

Move number 9: Blue to play 63

White	145
Blue	145
Position ID: 4LuDAQzYTuEBAw Match ID: QQkPAAAAAAAA

#		Ply	Move	Equity
	1	R	9/6 8/2	+0.0522
			0.5834 0.0925 0.0035 - 0.4166 0.0502 0.0014 +0.2113 +0.0522 0.0013 0.0017 0.0003 - 0.0013 0.0012 0.0003 0.0032 0.0046
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 1069425247 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	2	R	13/4	+0.0134 ( -0.0388)
			0.5556 0.1524 0.0042 - 0.4444 0.0724 0.0018 +0.1935 +0.0134 0.0019 0.0027 0.0004 - 0.0019 0.0016 0.0005 0.0047 0.0082
			Full cubeful rollout with var.redn.
			802 games, Mersenne Twister dice gen. with seed 1069425247 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]
	3	R	13/7 8/5	+0.0047 ( -0.0475)
			0.5567 0.1424 0.0036 - 0.4433 0.0708 0.0025 +0.1860 +0.0047 0.0016 0.0021 0.0004 - 0.0016 0.0013 0.0003 0.0041 0.0067
			Full cubeful rollout with var.redn.
			1296 games, Mersenne Twister dice gen. with seed 1069425247 and quasi-random dice
			Play: world class 2-ply cubeful prune [world class]
			keep the first 0 0-ply moves and up to 8 more moves within equity 0.16
			Skip pruning for 1-ply moves.
			Cube: 2-ply cubeful prune [world class]

Messages In This Thread

• Food for thought
  Matt Cohn-Geier -- Wednesday, 11 July 2007, at 5:08 p.m.
  • Food for thought
    Steve Mellen -- Wednesday, 11 July 2007, at 5:20 p.m.
  • Food for thought
    Chuck Bower -- Wednesday, 11 July 2007, at 5:32 p.m.
  • Food for thought
    Stick -- Wednesday, 11 July 2007, at 6:19 p.m.
  • Food for thought
    Philippe Michel -- Wednesday, 11 July 2007, at 8:15 p.m.
  • Rollout
    Matt Cohn-Geier -- Thursday, 12 July 2007, at 8:47 p.m.