FIBS Board backgammon forum

Backgammon => Fibsboard Forum Matches => FFM2 => Topic started by: diane on November 15, 2009, 01:07:19 AM

Poll
Question: Move?
Option 1: 24/20 (2), 13/9 (2) votes: 6
Option 2: 24/16 (2) votes: 2
Option 3: 24/20 (2), 13/5 votes: 0
Option 4: 24/20 (2), 13/9, 8/4 votes: 0
Option 5: 24/16, 13/9 (2) votes: 0
Title: Game 7, move 2 : Forum 4-4
Post by: diane on November 15, 2009, 01:07:19 AM
Forum, blue, to move 4-4

4PPEATDMTvABMA:UQmyADAAIAAA
Title: Re: Game 7, move 2 : Forum 4-4
Post by: ah_clem on November 15, 2009, 12:50:55 PM
Spoiler


The default thing to do with early double fours  is to make the opponent's 5 point and bring two down from the midpoint. 

However, at DMP the running play is attractive.  If we can then move the runners into our outfield and stay 20 pips ahead we should be in good shape to win.

Since we've already made the three, the nine point is not useful towards making a prime.  This is what sways me towards the running play.  But I don't have a strong sense which is better.

[close]
Title: Re: Game 7, move 2 : Forum 4-4
Post by: NIHILIST on November 15, 2009, 03:15:18 PM
Spoiler
Well, it's a great roll either way we play it, I don't think we want to give it back.

I feel strongly we should make the 20 and 9 points. Our position is formidable, but the game isn't over. If a hitting contest ensues I much prefer the anchor on his 5 point. At the same time making the 9 point gives us a lot more wood to make our 4 and 7 points.

If I've learned anything from the bots, it's that the best moves involve checker play on BOTH sides of the board. Making the 2 points clearly ( to me, anyway ) seems the more powerful play.

In our long-ago chouettes, if a player strongly opposed the captain's proposed play, he could buy the game for half the cube, sit down, and play it out himself. I'm pretty sure I'd buy the game here to make the 2 points.
[close]

Bob
Title: Re: Game 7, move 2 : Forum 4-4
Post by: diane on November 15, 2009, 04:37:15 PM
Quote from: NIHILIST on November 15, 2009, 03:15:18 PM
Spoiler
In our long-ago chouettes, if a player strongly opposed the captain's proposed play, he could buy the game for half the cube, sit down, and play it out himself. I'm pretty sure I'd buy the game here to make the 2 points.
[close]

Bob

Spoiler
I would buy half of *that* game, I hope that move to 19 isn't still in the lead tomorrow!!  :wacko:
[close]
Title: Re: Game 7, move 2 : Forum 4-4
Post by: dorbel on November 15, 2009, 08:20:35 PM
Spoiler
I'm pretty sure that 24/20(2), 13/9(2) is best, as NIHI says making progress on both sides of the board is usually right. Also, the stack on the 13pt with the blot on the 8pt is a notoriously weak and inflexible combination, so we need to grab this golden chance to correct such a glaring structual weakness. Note too how staying back on the 20pt exerts pressure on White's awkward stacks. If we step out to the 16pt White can start to build a prime by slotting the bar, 5 an 4pts.
[close]
Title: Re: Game 7, move 2 : Forum 4-4
Post by: ah_clem on November 15, 2009, 08:48:25 PM
Spoiler

Since I don't have a strong sense of which is better, I'm going to defer to Bob and Dorbel and change my vote.

I have lots of experience losing games while ahead in the match by playing too safe.  The running play fits that pattern.

[close]
Title: Re: Game 7, move 2 : Forum 4-4
Post by: NIHILIST on November 16, 2009, 12:10:52 AM
Spoiler
We all have plenty of that kind of experience.
[close]

Bob
Title: Re: Game 7, move 2 : Forum 4-4
Post by: diane on November 16, 2009, 12:30:57 AM
Quote from: ah_clem on November 15, 2009, 08:48:25 PM
Spoiler
I'm going to defer to Bob and Dorbel and change my vote.
[close]

Spoiler
Erm, I said that too  :wacko:    :laugh: :laugh:
[close]

I am better pleased with the direction of the vote now...perhaps I should lock it now.... :lol:
Title: Re: Game 7, move 2 : Forum 4-4
Post by: ah_clem on November 16, 2009, 05:36:52 PM
rollout


Spoiler


I've included both analysis and rollout as they differ.    The "standard" play is a slight favorite over the running play according to the rollout, but not by a statistically significant amount.  Both plays are sound. 





    1. Cubeful 2-ply    24/16(2)                     Eq.:  +0.371
       0.685 0.180 0.009 - 0.315 0.069 0.001
        2-ply cubeful prune [world class]
    2. Cubeful 2-ply    24/20(2) 13/9(2)             Eq.:  +0.369 ( -0.001)
       0.685 0.212 0.012 - 0.315 0.063 0.002
        2-ply cubeful prune [world class]
    3. Cubeful 2-ply    24/20(2) 13/5                Eq.:  +0.368 ( -0.003)
       0.684 0.222 0.013 - 0.316 0.059 0.001
        2-ply cubeful prune [world class]
    4. Cubeful 2-ply    24/20(2) 13/9 8/4            Eq.:  +0.324 ( -0.046)
       0.662 0.222 0.012 - 0.338 0.067 0.002
        2-ply cubeful prune [world class]


    1. Rollout          24/20(2) 13/9(2)             Eq.:  +0.371
       0.685 0.339 0.055 - 0.315 0.075 0.009 CL  +0.371 CF  +0.371
      [0.003 0.007 0.004 - 0.003 0.004 0.002 CL   0.005 CF   0.005]

    2. Rollout          24/16(2)                     Eq.:  +0.362 ( -0.009)
       0.681 0.290 0.039 - 0.319 0.084 0.007 CL  +0.362 CF  +0.362
      [0.002 0.007 0.003 - 0.002 0.004 0.001 CL   0.005 CF   0.005]

    3. Rollout          24/20(2) 13/5                Eq.:  +0.347 ( -0.024)
       0.673 0.346 0.052 - 0.327 0.082 0.008 CL  +0.347 CF  +0.347
      [0.002 0.007 0.004 - 0.002 0.004 0.002 CL   0.005 CF   0.005]

    4. Rollout          24/20(2) 13/9 8/4            Eq.:  +0.300 ( -0.071)
       0.650 0.315 0.049 - 0.350 0.114 0.012 CL  +0.300 CF  +0.300
      [0.002 0.007 0.004 - 0.002 0.005 0.002 CL   0.005 CF   0.005]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 869790528 and quasi-random dice
        Play: 0-ply cubeful prune [expert]
        Cube: 0-ply cubeful prune [expert]

[close]