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Backgammon => Fibsboard Forum Matches => FFM 7 => Topic started by: ah_clem on December 06, 2010, 12:08:58 AM

Poll
Question: 6-4?

Option 1: 13/3 votes: 0
Option 2: 13/7 8/4 votes: 4
Option 3: 13/7 6/2 votes: 0
Option 4: 8/2 6/2 votes: 5
Option 5: 7/1* 7/3 votes: 0
Option 6: 7/1* 8/4 votes: 0
Title: Game 5 Move 10 the Herd to play 6-4
Post by: ah_clem on December 06, 2010, 12:08:58 AM
(http://www.fibsboard.com/fibsboard-forum-match-7/game-5-move-10-the-herd-to-play-6-4/?action=dlattach;attach=5426;image)

6-4 to play
Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: ah_clem on December 06, 2010, 01:59:46 AM
Spoiler

My initial reaction to seeing 6-4 pop up was to make the 2 point.  Another homeboard point has to be the right move, right?

The problem with making the 2- point is that it strips all of  our points except the midpoint.  Having lots of points is great, but owning seven points means only one spare and our problem is not so much blocking his checkers as it is moving our men into the homeboard and off the board without leaving a shot. 

Another point is another point to clear, OTOH the two point gives a good landing spot and it's not going to be the difficult point to clear.

I suck at shot counting, but my attempt to count the shots  implies that simply making the two point leaves fewer  forced shots than the other options.  No, I'm not convinced I'm right, but I'm voting for making the two point.  If somebody wants to argue for another play I'm all ears. 

8/2 6/2


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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: PersianLord on December 06, 2010, 02:09:12 AM
Spoiler
13/7-8/4
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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: stog on December 06, 2010, 03:22:14 AM
Spoiler
i liked 13/3 at first, but i can go with pl's 13/7-8/4 which gives better flexibility -- which may not happen if we make the 2 point -- but that isn't such a bad play either - surely.

i think though by not making the 2 point we may keep a possible landing for our outfield a little longer ..and be able to deal better with some awkward rolls later -- what y'all think?
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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: diane on December 06, 2010, 08:34:20 AM
Spoiler
A comment I hear a lot in tournament play live where there is open consulting or chat, ie doubles, is 'prepare to clear', which is typically said when the number of checkers on the 13 is reduced to 2 as the players move into their home territory..
I never really got this...and am not sure if it is really easier to move two off the 13 than 3 or 4...any body got a good rationale for this statement?
In the meantime, because I don't know any better, and people who are much better at this game than me said it... I am going to prepare to clear  ;)  and I like PLs version of that...13/7, 8/4.
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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: stiefnu on December 06, 2010, 10:50:48 AM
Spoiler
I can't see too much wrong with making another home board point while keeping a spare on our mid for the time being.  8/2, 6/2 for me.
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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: ah_clem on December 06, 2010, 01:39:35 PM
Spoiler

I just counted the rolls that force us to leave a shot, and I come up with only 4-4 if we make the two point and I come up with 6-1 6-2 and 6-4 when we make the other play.  Six vs one.  That's a lot.

I do understand that the other play may give us more flexibility later, but in a few moves he'll have to abandon his midpoint (maybe even before our next shake) which will make clearing the midpoint much easier. When the opponent is running out of time to hold his defense, pay later is preferable to pay now.

I say pay later. The fact that we're making another homeboard point ices it for me.  We now have another landing spot in front of his straggler, and if we have to hit loose another point might keep him on the bar for a crucial roll or two.

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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: ah_clem on December 06, 2010, 10:12:45 PM
2 hours to go...get your vote in before it's too late.
Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: ah_clem on December 07, 2010, 12:50:10 AM
gnubg results

Spoiler


2-ply analysis has the two plays basically dead even.  0-ply rollout gives the edge to making the two point.

I'll start a 2-ply rollout, but that will take awhile.



//////////// 2-ply analysis  ////////////////////////////////////////
    1. Cubeful 2-ply    13/7 8/4                     Eq.:  +0.477
       0.766 0.159 0.004 - 0.234 0.028 0.000
        2-ply cubeful prune [world class]
    2. Cubeful 2-ply    8/2 6/2                      Eq.:  +0.473 ( -0.004)
       0.764 0.142 0.002 - 0.236 0.027 0.000
        2-ply cubeful prune [world class]
    3. Cubeful 2-ply    13/3                         Eq.:  +0.442 ( -0.035)
       0.751 0.164 0.005 - 0.249 0.030 0.001
        2-ply cubeful prune [world class]

//////////////  0-ply rollout /////////////////////////////////


    1. Rollout          8/2 6/2                      Eq.:  +0.519
       0.783 0.316 0.012 - 0.217 0.024 0.003 CL  +0.519 CF  +0.519
      [0.002 0.008 0.002 - 0.002 0.001 0.001 CL   0.004 CF   0.004]

    2. Rollout          13/7 8/4                     Eq.:  +0.496 ( -0.024)
       0.775 0.332 0.019 - 0.225 0.027 0.002 CL  +0.496 CF  +0.496
      [0.002 0.008 0.003 - 0.002 0.001 0.000 CL   0.004 CF   0.004]

    3. Rollout          13/3                         Eq.:  +0.459 ( -0.061)
       0.762 0.344 0.022 - 0.238 0.033 0.002 CL  +0.459 CF  +0.459
      [0.002 0.008 0.003 - 0.002 0.001 0.001 CL   0.004 CF   0.004]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 903655900 and quasi-random dice
        Play: 0-ply cubeful prune [expert]
        Cube: 0-ply cubeful prune [expert]


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Title: Re: Game 5 Move 10 the Herd to play 6-4
Post by: ah_clem on December 08, 2010, 12:59:33 PM
2-ply gnu rollout

Spoiler

    1. Rollout          8/2 6/2                      Eq.:  +0.502
       0.775 0.291 0.014 - 0.225 0.024 0.002 CL  +0.502 CF  +0.502
      [0.001 0.009 0.002 - 0.001 0.001 0.001 CL   0.003 CF   0.003]

    2. Rollout          13/7 8/4                     Eq.:  +0.492 ( -0.010)
       0.772 0.306 0.012 - 0.228 0.026 0.001 CL  +0.492 CF  +0.492
      [0.002 0.009 0.002 - 0.002 0.001 0.000 CL   0.004 CF   0.004]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 903655900 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 0.1
        Skip pruning for 1-ply moves.
        Cube: 2-ply cubeful prune [world class]

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