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Backgammon => Fibsboard Forum Matches => FFM 16 => Topic started by: diane on July 03, 2013, 03:23:33 AM

Poll
Question: Take?
Option 1: Take votes: 1
Option 2: Pass votes: 7
Title: Game 1, move 12 : Herd cube decision
Post by: diane on July 03, 2013, 03:23:33 AM
Well, do you like this?
Title: Re: Game 1, move 12 : Herd cube decision
Post by: KDP on July 03, 2013, 01:17:50 PM
Spoiler
do we WANT to take, no not really, but CAN we take?  yes i think so.  if the general rule of thumb is you have a take when you win 25% of the time, then i think we have more than that here.  i would guess we win maybe 30 to 35%.  the 2 main factors that would argue for the take are our anchor and our 5 prime.
[close]
Title: Re: Game 1, move 12 : Herd cube decision
Post by: Roderick on July 03, 2013, 02:05:09 PM
Spoiler
it's not the 22-23% takepoint you have to worry about.  You definitely have more than that with the 4 point anchor.  It's the effective win rate.  I bet I gammon you a little more than I get gammoned  :blink:
[close]
Title: Re: Game 1, move 12 : Herd cube decision
Post by: KDP on July 03, 2013, 03:45:51 PM
ok well it seems our gammon losses cancel out our wins.  that is something i didnt take into account initially.  im changing my vote to pass.  looks like i've learned something new, which i believe is the whole point of this exercise. :thumbsup2:
Title: Re: Game 1, move 12 : Herd cube decision
Post by: Linus on July 03, 2013, 06:41:27 PM
Spoiler
I think this is one of those positions gnubg likes to call "too good to double", so Roderick may have given the Herd a break here.
[close]
Title: Re: Game 1, move 12 : Herd cube decision
Post by: Roderick on July 04, 2013, 07:23:56 AM
Now that voting closed....

I wasn't 100% certain about my cube here.  The problem for me is that I need a 6 to escape and many of my rolls that would otherwise point I need to use to escape.  I don't come out from behind your prime nearly half the time after 2 rolls.  During that time you could easily make the 2nd anchor.  And besides that, I think, if memory serves (didn't review the position just now), I have a couple of rolls that are potentially bad immediately.  I have only a handful of rolls that pretty much take you out of it (6's and 5's).  4-5 gives you a chance for the 2nd anchor....  Most other rolls either have me leaving something or leave you with either an ace or deuce to make the second anchor, after which I would have a bare cube... maybe (had I not previously cubed).  Sure I get a bunch of gammons.  But I lose a lot of games.

Long and short of it...  I had a tenuous cube.  You had a take.
Title: Re: Game 1, move 12 : Herd cube decision
Post by: stog on July 04, 2013, 09:22:26 AM
also i wonder if this may be an easier take as this match is 7 point than if it had been the usual 5?
Title: Re: Game 1, move 12 : Herd cube decision
Post by: diane on July 04, 2013, 10:20:08 AM
Quote from: Roderick on July 04, 2013, 07:23:56 AM
Long and short of it...  I had a tenuous cube.  You had a take.

gnu would go so far as to insist we had a beaver  ;)

Will roll this out..
Title: Re: Game 1, move 12 : Herd cube decision
Post by: dorbel on July 04, 2013, 11:02:41 AM
If Gnu would beaver this you may have entered the position incorrectly. It is an easy take. Unlike our other sporting heroes who came to their decisions before consulting their bots, I have actually rolled this out with XG and a pass is a double blunder. Can we say why? The task Rod faces in escaping is not trivial. The average number of rolls needed to throw a 6 is 3.14. If he takes more than this, he will go bust on the other side, given that stack on his 6pt, then owning the cube will put the herd in a very strong position. It's an unpleasant take it's true, because things can go south very quickly. It is this volatility that triggers Rod's cube, because he has first-strike capability. The herd have to recognise that volatility works both ways here, not least because staying on the bar is actually quite good for them!
I certainly wouldn't blame anybody for passing, but the key features (the herd is anchored and on the bar, I, Rod still has to jump) apply to a lot of positions like this and taking is often easier than it looks, precisely because of that double-edged volatility.
Title: Re: Game 1, move 12 : Herd cube decision
Post by: diane on July 04, 2013, 12:30:26 PM
I didnt enter the position, it is being played in Gnu...I am not sure why the beaver came about - that is more a joke from the next thread...gnu says this..


(http://www.fibsboard.com/fibsboard-forum-match-16/game-1-move-12-herd-cube-decision/?action=dlattach;attach=8629;image)

Title: Re: Game 1, move 12 : Herd cube decision
Post by: Roderick on July 04, 2013, 01:41:15 PM
Like I said, I almost didn't cube.  Part of what pushed me to do so was the OTB "fear" factor.  Often, I've found even when there might be no cube, if the position looks bad enough you can get a drop.  The flip side is that sometimes you get the take and spend the rest of the game praying for good number after good number.

And, this position changes equity dramatically with just a few differences.  Unstuck my 6 popping a spare on each of my home board points and it might be close to a drop.