FIBS Board backgammon forum

Backgammon => Fibsboard Forum Matches => FFM4 => Topic started by: diane on May 02, 2010, 11:09:12 AM

Poll
Question: Move?
Option 1: 13/11, 13/8 votes: 2
Option 2: 24/22, 13/8 votes: 4
Option 3: 13/6 votes: 0
Option 4: 13/8, 6/4 votes: 0
Title: Game 5, move 1 : Forum 5-2
Post by: diane on May 02, 2010, 11:09:12 AM
There are a couple of sensible choices here, so I thought I would let you fight them out - and disregard the less sensible ones  ;)

Forum, blue, to move 5-2

mHPMATDg2+ABMA:cAm1ACAAGAAA
Title: Re: Game 5, move 1 : Forum 5-2
Post by: ah_clem on May 02, 2010, 01:07:26 PM
Spoiler
  13/6 is not a sensible move.  Neither is 13/8 6/4, although it's probably better and might make some sense at a different match score.

That leaves two options.  13/5 is a given, the question is whether to bring down a builder (13/11) or activate a runner (24/22).  Normally, I like to bring down the builder in an early move, but Blitzxz has already started building a blockade so I'm leaning toward splitting. Try to escape a checker or make an anchor.  Yes this is defensive and perhaps prematurely so, but I've been dinged by gnubg too many times for leaving my runners pat while my opponent bulids a blockade.

13/8 24/22


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Title: Re: Game 5, move 1 : Forum 5-2
Post by: stog on May 02, 2010, 09:35:44 PM
Spoiler
and yes he will attack with a name like blitzxz - so i like us to stay solid and get ourselves a bit of a board first -- i like the patient 13/8 13/11
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Title: Re: Game 5, move 1 : Forum 5-2
Post by: dorbel on May 03, 2010, 09:54:03 PM
What we are trying to do here is to find the play that loses the least gammons. Splitting at the back maximises our chances of making the high anchor that will dramatically cut our gammon risk. Playing 13/8, 13/11 will often lead to a difficult and potentially gammonish prime v. prime game. When we split, we will probably be attacked but the danger of being successfully blitzed is less than the danger of being primed.
Paradoxically, for those who fear the blitz, splitting forces the opponent to attack, generating lots of return shots when he has to hit loose!
Title: Re: Game 5, move 1 : Forum 5-2
Post by: ah_clem on May 04, 2010, 06:55:48 PM
Rollout:

Spoiler


Bringing down a builder only loses slightly more gammons than the forum's choice (within the margin of error).  But splitting wins many more games and a few more gammons as well.  Staying on the ace point and waiting to lose is not the way to go here.



    1. Rollout          24/22 13/8                   Eq.:  -0.412
       0.453 0.190 0.026 - 0.547 0.166 0.020 CL  -0.247 CF  -0.412
      [0.002 0.005 0.003 - 0.002 0.002 0.002 CL   0.006 CF   0.015]
       
    2. Rollout          13/11 13/8                   Eq.:  -0.533 ( -0.121)
       0.432 0.182 0.028 - 0.568 0.169 0.040 CL  -0.291 CF  -0.533
      [0.003 0.005 0.003 - 0.003 0.002 0.004 CL   0.006 CF   0.017]
       
    3. Rollout          13/8 6/4                     Eq.:  -0.554 ( -0.141)
       0.432 0.166 0.026 - 0.568 0.175 0.047 CL  -0.298 CF  -0.554
      [0.003 0.005 0.003 - 0.003 0.002 0.004 CL   0.006 CF   0.017]

    4. Rollout          13/6                         Eq.:  -0.765 ( -0.353)
       0.399 0.160 0.023 - 0.601 0.188 0.035 CL  -0.375 CF  -0.765
      [0.002 0.005 0.003 - 0.002 0.002 0.003 CL   0.006 CF   0.015]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 854751941 and quasi-random dice
        Play: 0-ply cubeful prune [expert]
        Cube: 0-ply cubeful prune [expert]

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