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Backgammon => Fibsboard Forum Matches => FFM 7 => Topic started by: ah_clem on November 15, 2010, 12:19:33 PM

Poll
Question: 6-2?
Option 1: 24/16 votes: 2
Option 2: 24/18 13/11 votes: 5
Option 3: 24/22 13/7 votes: 0
Option 4: 13/5 votes: 0
Option 5: 13/11 8/2* votes: 0
Option 6: 24/22 8/2* votes: 0
Option 7: 13/7 13/11 votes: 0
Title: Game 4 move 1 The Herd to play 6-2
Post by: ah_clem on November 15, 2010, 12:19:33 PM
(http://www.fibsboard.com/fibsboard-forum-match-7/game-4-move-1-the-herd-to-play-6-2/?action=dlattach;attach=5283;image)

We roll a 6-2.
Title: Re: Game 4 move 1 The Herd to play 6-2
Post by: ah_clem on November 15, 2010, 03:01:03 PM
Spoiler

Slotting the opponent's bar point and bringing down a builder is the "book" move for the opening roll for money or for early match scores.

But at this match score we're just trying to win a single point and I believe simply running wins the most games.  

I might play 24/18 13/11 at other match scores, but not here.  24/16.


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Title: Re: Game 4 move 1 The Herd to play 6-2
Post by: ah_clem on November 16, 2010, 01:56:05 AM
^^^^^^^^^^^^^^
Title: Re: Game 4 move 1 The Herd to play 6-2
Post by: diane on November 16, 2010, 06:25:18 AM
^^^^^^^^^^^^^^

Spoiler
I disagreed btw...I am one of the 4 - I never like the run, it seems like I am putting one out to get hit and end up back at the beginning, wheras with the split, I have a chance that one of them will achieve something...
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Title: Re: Game 4 move 1 The Herd to play 6-2
Post by: ah_clem on November 16, 2010, 11:34:33 AM
Spoiler
Quote from: diane on November 16, 2010, 06:25:18 AM
^^^^^^^^^^^^^^

I disagreed btw...I am one of the 4 - I never like the run, it seems like I am putting one out to get hit and end up back at the beginning, wheras with the split, I have a chance that one of them will achieve something...
The thing is, the split to the 18 gives your opponent a double shot so you're even more likely to be hit there.  The split gives better gammon chances, but the  run wins more games.  Normally the extra gammons tip the balance, but here we don't care about gammons.

Anyway, the vote is over and I'll have a rollout in a few...

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Title: Re: Game 4 move 1 The Herd to play 6-2
Post by: ah_clem on November 16, 2010, 11:58:35 AM
rollout

Spoiler


The Herd's choice is certainly playable but slightly inferior to the running play. Why is the running play best?  My impression was that the running play as an opening roll won the most games, but this is incorrect ( see http://www.bgonline.org/firstmove/26.html (http://www.bgonline.org/firstmove/26.html) or http://www.bkgm.com/openings.html#opening62 (http://www.bkgm.com/openings.html#opening62) )  The thing is, this isn't an opening roll - Z has already split his backmen so the opening rollouts aren't going to be quite correct. 

Stick has rollouts of 2nd moves (for money play) at http://www.bgonline.org/secondmove/15/26.html (http://www.bgonline.org/secondmove/15/26.html) and it shows that running is better in a money situation.  This rollout is nearly identical to Stick's (at a very differrent match score situation) so I'd surmise that it has to do with the split backmen - he's split so our builders are in more danger, plus we're under pressure to get our own bakckmen moving.  I'm just starting to realize the utility of the early split and how it changes the play all over the board, so I'm not qualified to pontificate on it.  Maybe someone else can...




    1. Rollout          24/16                        Eq.:  -0.058
       0.479 0.148 0.015 - 0.521 0.150 0.005 CL  -0.058 CF  -0.058
      [0.002 0.005 0.002 - 0.002 0.002 0.001 CL   0.005 CF   0.005]

    2. Rollout          24/18 13/11                  Eq.:  -0.080 ( -0.022)
       0.469 0.160 0.015 - 0.531 0.154 0.007 CL  -0.080 CF  -0.080
      [0.002 0.005 0.002 - 0.002 0.002 0.001 CL   0.005 CF   0.005]

    3. Rollout          24/22 24/18                  Eq.:  -0.099 ( -0.041)
       0.459 0.141 0.015 - 0.541 0.161 0.006 CL  -0.099 CF  -0.099
      [0.002 0.005 0.002 - 0.002 0.003 0.001 CL   0.005 CF   0.005]

    4. Rollout          13/5                         Eq.:  -0.110 ( -0.052)
       0.456 0.174 0.020 - 0.544 0.169 0.009 CL  -0.110 CF  -0.110
      [0.003 0.005 0.002 - 0.003 0.003 0.001 CL   0.006 CF   0.006]

    5. Rollout          24/18 8/6                    Eq.:  -0.118 ( -0.061)
       0.449 0.140 0.018 - 0.551 0.157 0.005 CL  -0.118 CF  -0.118
      [0.002 0.005 0.002 - 0.002 0.002 0.001 CL   0.005 CF   0.005]

    6. Rollout          13/11 8/2*                   Eq.:  -0.121 ( -0.063)
       0.451 0.170 0.022 - 0.549 0.181 0.010 CL  -0.121 CF  -0.121
      [0.002 0.005 0.003 - 0.002 0.003 0.001 CL   0.005 CF   0.005]
        Full cubeful rollout with var.redn.
        1296 games, Mersenne Twister dice gen. with seed 905458359 and quasi-random dice
        Play: 0-ply cubeful [expert]
        Cube: 0-ply cubeful [expert]


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Title: Re: Game 4 move 1 The Herd to play 6-2
Post by: Zorba on November 23, 2010, 12:27:08 PM
Catching up a bit with some older posts...

The matchscore is a factor; running is always good for winning single games but not so much for gammons, whereas builders that can create homeboard points are especially useful for gammons.

My split backcheckers mean that 13/11 now gets hit not just with tens (6-4 only as 5-5 is blocked, so 2 shots), but also with nines (6-3, 5-4, 3-3: 5 shots extra) which makes it 7 shots instead of 2, quite a difference!

Also, the blot after 24/16 gets hit with fours but it duplicates a few already great rolls for me: 3-1 to make my five point; 4-3 which would make my 20pt anchor; 4-2 which would make my fourpoint, so that's already six hitting numbers where I don't gain that much extra from hitting.