FIBS Board backgammon forum

Backgammon => Fibsboard Forum Matches => FFM2 => Topic started by: diane on October 01, 2009, 09:27:13 PM

Poll
Question: Move?
Option 1: 16/9 votes: 0
Option 2: 13/6 votes: 1
Option 3: 13/10, 13/9 votes: 8
Option 4: 13/9, 4/1* [ok, they are getting silly] votes: 0
Title: Game 5, move 6 : Forum 4-3
Post by: diane on October 01, 2009, 09:27:13 PM
After our hit, rkb danced with 6-4 and we went on to roll 4-3, therefore forum, blue, to move 4-3

bBvwMQDMtoMBUA:MAG6ACAAGAAA

zLaDAVBsG/AxAA:cAmuACAAGAAA
Title: Re: Game 5, move 6 : Forum 4-3
Post by: ah_clem on October 01, 2009, 10:56:28 PM
Spoiler

While this might be a good opportunity to clear the 16 point, what with him on the bar and all, I think bringing down two builders is the way to go.  He can't hit them, so it's perfectly safe and offers lots of chances to make another point or safety them if rkb enters them next time.  When your opponent is stuck on the bar, spread your men around to give the greatest flexibility.

13/10 13/9

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Title: Re: Game 5, move 6 : Forum 4-3
Post by: vikingblood80 on October 02, 2009, 08:40:33 AM
Spoiler

spread the builders 13/9 13/10 for the crucial bar- and 8 point here to extend the prime. On the 9 and 10 they are not in danger at all..no need to be anxious and play 13/6 here.
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Title: Re: Game 5, move 6 : Forum 4-3
Post by: dorbel on October 02, 2009, 08:41:56 AM
cube action?
Title: Re: Game 5, move 6 : Forum 4-3
Post by: stiefnu on October 02, 2009, 11:01:32 AM
Quotecube action?

Spoiler
Well, I might have been tempted to push that cube across.  One on the bar, another on the ace point - food for thought, surely.  And, if it were taken, the inevitable re-cube would certainly speed things along nicely. :laugh:
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Title: Re: Game 5, move 6 : Forum 4-3
Post by: ah_clem on October 02, 2009, 03:05:29 PM
Quote from: dorbel on October 02, 2009, 08:41:56 AM
cube action?
Spoiler
Since we're 2 away we have to be careful about cubing since a take will be followed by a recube and then we're playing for the match (and basically throwing away our 3-2 lead)

Also, there are serious gammon chances here, so it may be too good to double.  Usually you need to win twice as many gammons as single-point losses to justify playing on instead of cashing, but that's distorted by the match score.  At this match score the window between double and too-good is narrower than usual, so that may make the decisions harder, but it leads me to think that it's less likely that the position falls within the window - so, unless I'm sure the default is to hold the cube.

It's also not too terribly volatile so missing a double here is probably not too costly.

So, it might well be a double, but I'd sit on the cube for a move or two.

That said, we should probably have a cube vote before our next roll.

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BTW, it looks like we've got a consensus on the move here, so we might think about nexting the decision...
Title: Re: Game 5, move 6 : Forum 4-3
Post by: diane on October 02, 2009, 07:21:05 PM
Yes, there is a consensus, and now I am back from work, I will move it on - the cube will have to be voted on though - because some clearly want it, and others dont, so this is not clear cut.
Title: Re: Game 5, move 6 : Forum 4-3
Post by: ah_clem on October 04, 2009, 01:07:29 AM
Quote from: dorbel on October 02, 2009, 08:41:56 AM
cube action?

gnubg rollout of cube decision:

Spoiler


This is where we missed our double.  The correct thing would have been to cash this as it's a huge pass.  It's not a huge error to hold the cube, however.





Cube analysis
Rollout cubeless equity  +0.841 (Money:  +0.724)

Cubeful equities:
1. Double, pass         +1.000
2. Double, take         +1.129  ( +0.129)
3. No double            +0.943  ( -0.057)
Proper cube action: Double, pass
Rollout details:
Centered 1-cube:
  0.737 0.303 0.017 - 0.263 0.067 0.003 CL  +0.841 CF  +0.943
[0.001 0.004 0.002 - 0.001 0.002 0.001 CL   0.006 CF   0.010]
Player rkb owns 2-cube:
  0.764 0.337 0.037 - 0.236 0.060 0.004 CL  +1.729 CF  +1.129
[0.002 0.007 0.004 - 0.002 0.003 0.001 CL   0.011 CF   0.017]
Full cubeful rollout with var.redn.
1296 games, Mersenne Twister dice gen. with seed 871181490 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 6 : Forum 4-3
Post by: ah_clem on October 04, 2009, 03:14:20 AM

gnubg rollout checker play

Spoiler


No surprises here.


    1. Rollout          13/10 13/9                   Eq.:  +1.003
       0.757 0.287 0.022 - 0.243 0.056 0.004 CL  +0.790 CF  +1.003
      [0.002 0.005 0.003 - 0.002 0.002 0.001 CL   0.006 CF   0.012]
       
    2. Rollout          13/6                         Eq.:  +0.920 ( -0.084)
       0.729 0.305 0.025 - 0.271 0.066 0.005 CL  +0.749 CF  +0.920
      [0.002 0.005 0.003 - 0.002 0.002 0.001 CL   0.007 CF   0.012]
       
    3. Rollout          16/9                         Eq.:  +0.835 ( -0.168)
       0.727 0.251 0.020 - 0.273 0.069 0.004 CL  +0.703 CF  +0.835
      [0.001 0.004 0.002 - 0.001 0.003 0.001 CL   0.006 CF   0.011]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 871181490 and quasi-random dice
        Play: 0-ply cubeful prune [expert]
        Cube: 0-ply cubeful prune [expert]


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