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FIBS Board backgammon forum

Backgammon => Fibsboard Forum Matches => FFM2 => Topic started by: Zorba on July 07, 2009, 02:06:32 PM

Poll
Question: 4-2?
Option 1: 9/3 votes: 9
Option 2: 6/4 6/2 votes: 0
Option 3: 6/2 3/1 votes: 0
Title: Game 2, move 7: Forum 4-2
Post by: Zorba on July 07, 2009, 02:06:32 PM
4W4zAAPrZhwABg:cAmxABAAAAAA

Forum (blue) 4-2
Title: Re: Game 2, move 7: Forum 4-2
Post by: vikingblood80 on July 07, 2009, 03:48:40 PM
Spoiler
Not many opportunities, at least we rolled no disaster. Just play anti-gammon and save here and wait what will happen.. 9/3
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Title: Re: Game 2, move 7: Forum 4-2
Post by: blitzxz on July 07, 2009, 03:54:07 PM
Good roll!
Title: Re: Game 2, move 7: Forum 4-2
Post by: diane on July 07, 2009, 06:56:00 PM
Spoiler
Yup, 9-3 and wait and see  ;)
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Title: Re: Game 2, move 7: Forum 4-2
Post by: stog on July 07, 2009, 06:59:00 PM
Spoiler
9/3 is  lookin a given
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Title: Re: Game 2, move 7: Forum 4-2
Post by: ah_clem on July 07, 2009, 09:19:30 PM
Spoiler
I can see some logic behind 6/2 3/1, but I don't have the guts to play it over the board.  It's one of those bot moves that may be correct.  Or not.

9/3 for me.
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Title: Re: Game 2, move 7: Forum 4-2
Post by: Zorba on July 07, 2009, 09:55:36 PM
Spoiler
9/3 for me too, but that extra spare on the three point is really ugly, and we have a blot on the twopoint to worry about, that is not easily covered or lifted. Since the game is getting to some sort of climax soon, it would be nice to have our act cleaned up so we can at least limit the risks when we are gonna run (or hit an indirect shot even), or when blitzxz runs a checker and we want to attack. So 6/4 6/2 deserves a good look. I always find it hard to judge plays like that and in the end I couldn't bring myself to play it, but I sure want to hear the bot's verdict on that move!
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Title: Re: Game 2, move 7: Forum 4-2
Post by: diane on July 08, 2009, 12:05:27 AM
Quote from: Zorba on July 07, 2009, 09:55:36 PM
Spoiler
9/3 that extra spare on the three point is really ugly, and we have a blot on the twopoint to worry about, that is not easily covered or lifted.
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agree, but what else, we must just face it  ;)
Title: Re: Game 2, move 7: Forum 4-2
Post by: playBunny on July 08, 2009, 01:17:00 PM
Quote from: diane on July 08, 2009, 12:05:27 AM
agree, but what else, we must just face it  ;)

Yep, let's face the music and dance but hope not to dance.
Title: Re: Game 2, move 7: Forum 4-2
Post by: Zorba on July 08, 2009, 02:55:34 PM
9/3 NEXTED
Title: Re: Game 2, move 7: Forum 4-2
Post by: diane on July 08, 2009, 05:58:40 PM
Quote from: playBunny on July 08, 2009, 01:17:00 PM
but hope not to dance.

:laugh: :laugh: that is a common bg prayer, I am sure  ;)
Title: Re: Game 2, move 7: Forum 4-2
Post by: roadkillbooks on July 08, 2009, 06:39:36 PM
Spoiler
4-2 was a maintain the status quo roll nothing much changed.  I am surprised at the unanimity of this decision.  If we look into break numbers 6/4, 6/2 doesn't leave a blot
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on that side of the board with any number as even 6-4 can play because the 4 is blocked...of course losing the 6 point is a crunch in itself but it guarantees that I wont hit a  blot and that ill leave.  I guess in that option the forum game plan is to get into a race.  But I agree I hate breaking my  point and there is almost no way id play that over the board...but when you can sit staring at things as if it were the sunday crossword puzzle... different things come up.
Title: Re: Game 2, move 7: Forum 4-2
Post by: playBunny on July 08, 2009, 07:00:08 PM
Quote from: Zorba on July 07, 2009, 09:55:36 PM
6/4 6/2 deserves a good look. I always find it hard to judge plays like that and in the end I couldn't bring myself to play it, but I sure want to hear the bot's verdict on that move![/spoiler]

Rollout 2592 trials, 2-ply throughout

Spoiler
Indeed it does deserve a good look. I saw 6/4 6/2 and thought that it was probably the kind of thing that would appeal to the bot. It creates a solid 4-point table and (with a superficial examination) didn't look to leave as many blots next go as moving our 8-point's spare into the home. But, like zorba, I couldn't go for it either. A deeply ingrained reluctance to give up the 6-point? A sense of horror at having both the 5-point and 6-point empty? Who knows. ;)

It turns out that 6/4 6/2 is the bot move - at all evaluation levels.

Cubeful 2-ply
# .. Move ...... Equity . (Diff) ... Win ..... WinG .. WinBg -- Lose ... LoseG . LoseBg
1 .. 6/4 6/2 ... -0.408 ............ 40.0% ... 6.4% ... 0.0% -- 60.0% .. 11.4% ... 0.1%
2 .. 9/3 ....... -0.420 (-0.013) ... 39.5% ... 7.6% ... 0.1% -- 60.5% .. 11.6% ... 0.2%

Cubeful 3-ply
# .. Move ...... Equity . (Diff) ... Win ..... WinG .. WinBg -- Lose ... LoseG . LoseBg
1 .. 6/4 6/2 ... -0.512 ............ 37.9% ... 7.3% ... 0.1% -- 62.1% .. 13.8% ... 0.2%
2 .. 9/3 ....... -0.531 (-0.020) ... 37.4% ... 7.8% ... 0.1% -- 62.6% .. 13.8% ... 0.2%

Cubeful 4-ply
# .. Move ...... Equity . (Diff) ... Win ..... WinG .. WinBg -- Lose ... LoseG . LoseBg
1 .. 6/4 6/2 ... -0.456 ............ 39.6% ... 6.7% ... 0.0% -- 60.4% .. 11.9% ... 0.2%
2 .. 9/3 ....... -0.461 (-0.005) ... 39.1% ... 7.8% ... 0.1% -- 60.9% .. 12.1% ... 0.3%

But when the bot is asked "Do you really think so?", it demurs and admits that 6/4 6/2 would be a bad move. Furthermore the equities are much more pessimistic than the evaluations.

Rollout 2592 trials, 2-ply throughout
# .. Move ...... Equity . (Diff) ... Win ..... WinG .. WinBg -- Lose ... LoseG . LoseBg
1 .. 9/3 ....... -0.651 ............ 37.2% ... 7.8% ... 0.1% -- 62.8% .. 13.2% ... 1.2%
2 .. 6/4 6/2 ... -0.707 (-0.056) ... 36.7% ... 7.2% ... 0.1% -- 63.3% .. 14.4% ... 0.9%
Std Err ......... 0.007 ............. 0.1% ... 0.1% ... 0.0% --- 0.1% ... 0.2% ... 0.1%
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