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FIBS Board backgammon forum

Backgammon => Fibsboard Forum Matches => FFM2 => Topic started by: Zorba on July 29, 2009, 09:53:22 PM

Poll
Question: Cube action?
Option 1: DOUBLE votes: 11
Option 2: NO DOUBLE votes: 2
Title: Game 3, move 10: roadkillbooks 2-6 FORCED, move 11: Forum cube?
Post by: Zorba on July 29, 2009, 09:53:22 PM
The Forum decided to hit loose 8/4* on its last turn, roadkillbooks rolls a 2-6 from the bar to enter one checker. Cube decision for the Forum (blue):

jDN4wEiznGCCIQ:cAmgACAAAAAA

Title: Re: Game 3, move 10: roadkillbooks 2-6 FORCED, move 11: Forum cube?
Post by: ah_clem on July 30, 2009, 05:38:07 AM
Spoiler

A 37 pip lead. 
We threaten to make a fourth point in our homeboard.  Any 4,  any 2 and especially 6-2 is devastating.
We have a three point board vs a two point board.

That's three for three in the position-race-threats triumvirate.  Market losers abound.  So definitely good enough.

The question is, is it too good?  Maybe, but lots can still happen here, and with rkb holding the golden anchor gammon chances are slim.

DOUBLE.

Looks like a pass at this match score, but rkb may surprise me here. 

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Title: Re: Game 3, move 10: roadkillbooks 2-6 FORCED, move 11: Forum cube?
Post by: blitzxz on July 30, 2009, 03:00:40 PM
Spoiler
This would be far from double in even score. High anchor is so strong asset and we have still major part of our army far from home. The game (and holding) will continue long time and rkb will have lot chances to hit and even up. However in this score I would double. There are some gammons lurking around and we don't want lose them with market loser sequences. If I were on take/pass side I would have to stop for awhile to think (because score) but looks like a take. Gammons can't be pass high because solid anchor.
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Title: Re: Game 3, move 10: roadkillbooks 2-6 FORCED, move 11: Forum cube?
Post by: ah_clem on July 31, 2009, 03:31:20 AM
Next?
Title: Re: Game 3, move 11: roadkillbooks DROP/TAKE?
Post by: Zorba on August 01, 2009, 03:47:51 PM
The Forum doubled, will roadkillbooks take? See the diagram at the start of the thread.

Title: Re: Game 3, move 10: roadkillbooks 2-6 FORCED, move 11: Forum cube?
Post by: roadkillbooks on August 01, 2009, 06:03:44 PM
TAKE. Seems like a simple trivial take even at this match score. I like my anchor and right now I have only one piece in the air.  If I had danced it might be different.


Title: Re: Game 3, move 10: roadkillbooks 2-6 FORCED, move 11: Forum cube?
Post by: Zorba on August 05, 2009, 04:08:02 PM
GnuBG 2-ply rollout of cube decision:

Spoiler

It's a double, but not by all that much. We win only about 59% of the games here.  It's the very high gammon rate, medium volatility and the matchscore that turn this into a double.

Rollout details:
Centered 1-cube (NO DOUBLE):
   58,51  26,44   0,69 -  41,49   9,84   0,97 CL  +0,3932 CF  +0,6435 (-0,0389)
[  0,12   0,14   0,03 -   0,12   0,15   0,24 CL   0,0037 CF   0,0075]
Player roadkillbooks owns 2-cube (DOUBLE/TAKE):
   58,97  26,73   0,37 -  41,03  10,10   1,53 CL  +0,8397 CF  +0,6824
[  0,14   0,17   0,04 -   0,14   0,21   0,28 CL   0,0082 CF   0,0093]

Full cubeful rollout with var.redn.
2592 games, Mersenne Twister dice gen. with seed 861201809 and quasi-random dice
Play:  2-ply cubeful prune [world class]
keep the first 0 0-ply moves and up to 8 more moves within equity 0,13
Skip pruning for 1-ply moves.
Cube: 2-ply cubeful prune [world class]

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