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how would you play this without peeking

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08-23-2012 , 07:13 AM

yogiman

adept

Join Date: Jun 2012 Posts: 784

White - Pips 115. Match Score 0/7

Black - Pips 168. Match Score 0/7
Black to Play 2-1
Created with www.BGdiagram.com

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08-23-2012 , 09:22 AM

Robertie

old hand

Join Date: May 2004 Posts: 1,954

Make the 5-point, and it's probably not close. If you make the point, your opponent's rolls break down into four categories:

(1) Fan - 9 rolls
(2) Enter without hitting - 13 rolls
(3) Hit followed by your entering - 10 rolls
(4) Hit followed by your fanning - 4 rolls

(1) leads to an immediate redouble on your part.
(2) gives you a solid edge.
(3) you're OK, much depends on whether you can safety the 11-point blot or not.
(4) you get gammoned a lot.

You're picking up lots of wins with (1), (2), and (3), and giving back some gammons in (4). But (4) only happens 11% of the time, and new games won are twice as valuable as new gammons lost, so make the 5-point.

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08-23-2012 , 09:27 AM

RealNick

journeyman

Join Date: Apr 2010 Posts: 217

I make the 5 without a whole lot of thought. Seems clear.

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08-23-2012 , 10:09 AM

yogiman

adept

Join Date: Jun 2012 Posts: 784

Makes clear to me why i am just an enthusiast.

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08-23-2012 , 10:18 AM

yogiman

adept

Join Date: Jun 2012 Posts: 784

(3) Hit followed by your entering - 10 rolls
(4) Hit followed by your fanning - 4 rolls

Seems to me to be the other way around?

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08-23-2012 , 12:28 PM

uberkuber

veteran

Join Date: Jul 2009 Posts: 3,032

With White having a 5-pt board and gammons counting in that tournament setting, I'g do for something safe with 15/14 13/11.

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08-23-2012 , 12:31 PM

uberkuber

veteran

Join Date: Jul 2009 Posts: 3,032

Quote:

Originally Posted by yogiman

(3) Hit followed by your entering - 10 rolls
(4) Hit followed by your fanning - 4 rolls

Seems to me to be the other way around?

+1 Doesn't make sense otherwise.

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08-23-2012 , 12:56 PM

Robertie

old hand

Join Date: May 2004 Posts: 1,954

Quote:

Originally Posted by yogiman

(3) Hit followed by your entering - 10 rolls
(4) Hit followed by your fanning - 4 rolls

Seems to me to be the other way around?

You are correct. Sorry about that. I still make the 5-point, though.

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08-23-2012 , 04:57 PM

yogiman

adept

Join Date: Jun 2012 Posts: 784

Thanks for the reply, mr. Robertie, no doubt you have got also other things on your mind.

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08-25-2012 , 05:42 PM

#10

yogiman

adept

Join Date: Jun 2012 Posts: 784

I want to request Taper_Mike to compare the XG result.

1. Cubeful 2-ply 7/5* 6/5 Eq.: +0,155
0,577 0,149 0,002 - 0,423 0,272 0,017
2-ply cubeful prune [world class]
2. Cubeful 2-ply 15/14 13/11 Eq.: -0,031 ( -0,186)
0,521 0,108 0,002 - 0,479 0,200 0,004
2-ply cubeful prune [world class]

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08-26-2012 , 12:24 AM

#11

Taper_Mike

adept

Join Date: Sep 2009 Posts: 1,030

White - Pips 115. Match Score 0/7

Black - Pips 168. Match Score 0/7
Black to Play 2-1

Quote:

Originally Posted by yogiman

I want to request Taper_Mike to compare the XG result.

Glad to. As it turns out, I had already posted this very interesting position into my flashcard collection. I fell right into the trap, playing Z = Reverse split (15/14 13/11). Bill’s explanantion why that is 2nd-best is excellent.

BTW: The trick to posting rollouts and evals is to put them inside “code” tags. This is accomplished by clicking the # icon in the editor.

Code:

XGID=--aaBaCB---A-C-A-b-bbCbbb-:1:1:1:21:0:0:3:0:10
 
X:Player 1   O:Player 2
Score is X:0 O:0. Unlimited Game, Jacoby Beaver
Pip count  X: 168  O: 115 X-O: 0-0
Cube: 2, X own cube
X to play 21
 
    1. XG Roller++ 7/5* 6/5                     eq:+0.181
      Player:   54.97% (G:15.18% B:0.52%)
      Opponent: 45.03% (G:29.28% B:1.02%)
 
    2. XG Roller++ 15/14 13/11                  eq:+0.086 (-0.095)
      Player:   50.36% (G:11.83% B:0.49%)
      Opponent: 49.64% (G:22.30% B:0.33%)
 
    3. XG Roller++ 13/11 6/5*                   eq:-0.054 (-0.235)
      Player:   48.27% (G:12.10% B:0.44%)
      Opponent: 51.73% (G:32.62% B:0.54%)
 
    4. XG Roller++ 6/5* 5/3*                    eq:-0.083 (-0.264)
      Player:   47.23% (G:11.82% B:0.49%)
      Opponent: 52.77% (G:32.21% B:0.85%)
 
 
eXtreme Gammon Version: 2.03

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08-26-2012 , 03:36 AM

#12

yogiman

adept

Join Date: Jun 2012 Posts: 784

Thanks Taper_mike, just what i feared. How can the difference be so huge?

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08-26-2012 , 04:39 AM

#13

Taper_Mike

adept

Join Date: Sep 2009 Posts: 1,030

Quote:

Originally Posted by yogiman

Thanks Taper_mike, just what i feared. How can the difference be so huge?

Why is there such a difference between the two top-ranked plays?

Bill gave the hint. When you put your opponent on the roof, fully 25% of the games end on the next roll, after a dance. The position is not just a double then; it becomes a pass. Any alternative play that does not offer a similar quick end to the game is going to have to be very strong across all rolls if it is going to be competitive.

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08-26-2012 , 04:39 AM

#14

yogiman

adept

Join Date: Jun 2012 Posts: 784

Another one of a same category:

White - Pips 70. Match Score 0/7

Black - Pips 75. Match Score 0/7
Black to Play 2-6
Created with www.BGdiagram.com

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08-26-2012 , 04:47 AM

#15

Taper_Mike

adept

Join Date: Sep 2009 Posts: 1,030

This new position may seem to be similar to the first, but it is actually quite different. It hinges on a very common theme.

If you do not hit, your opponent will likely escape, and enter into an even race. Your chance of winning will be roughly 50%. If you hit, on the other hand, then most of your opponent’s racing chances go out the window. In order to win, he must hit back. And for that, he has only 13 rolls in 36 (approx. 35%).

When you look at it that way, the choice is easy.

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08-26-2012 , 05:40 AM

#16

yogiman

adept

Join Date: Jun 2012 Posts: 784

What i mean is that the gammon weight is much less than expected.

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08-26-2012 , 05:46 AM

#17

yogiman

adept

Join Date: Jun 2012 Posts: 784

Sorry, i didn't read your next to last post. Again i mean something else, that is, the gnubg evaluation is so very different from XG.

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