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Offline Shawn Ligocki
 Post subject: Go by example: Defer capture until forced. Why is this safe?
Post #1 Posted: Sat Dec 28, 2013 1:05 am 
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I just started reading "Go by example: Correcting common mistakes in double digit kyu play" by Neil Moffatt and I ran into an example that doesn't make sense to me.

It's in the section "Defer capture until forced!". Here's the setup:

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O 2 O 1 . . . . . . . . . . |
$$ | . . O . 3 O X O X . . . . O O . . . . |
$$ | . . X O O X 4 X . . . . X X O . . . . |
$$ | . . . X . X X . . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


White has made a simple mistake, trying to save her stones with :w2: and now black will get the whole group.

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O . X O . O X . . . . O O . . . . |
$$ | . . X O O X O X . . . . X X O . . . . |
$$ | . . . X . X X . . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


The question is where should black play next? The book explains that this is a common mistake for black:

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . 5 O O O X . . . . . . . . . . |
$$ | . . O . X O . O X . . . . O O . . . . |
$$ | . . X O O X O X . . . . X X O . . . . |
$$ | . . 6 X . X X . . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


Which allows white to live in the corner. Instead black should be ignore the already dead white group and attack the corner:

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O 5 X O . O X . . . . O O . . . . |
$$ | . . X Q Q X O X . . . . X X O . . . . |
$$ | . . . X . X X . . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


To capture the triangled stones and the entire corner.

But I don't understand how this is safe for black. It looks like this will allow white to escape:

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O O O Y . . . . . . . . . . |
$$ | . . O 5 X O . O Y 8 . . . O O . . . . |
$$ | . . X O O X O X 6 . . . X X O . . . . |
$$ | . . . X . X X 7 . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


At this point black cannot save his 2 triangled stones and it looks like white can escape. Shouldn't black have atari-ed the large group to avoid this? Or is there some better play for black? Reason that this escape plan doesn't succeed?

After looking at this for a bit I guess black could play like this:

Click Here To Show Diagram Code
[go]$$Bm9
$$ -------------------
$$ | . . . . . O O O X 2 . . . . . . . . . |
$$ | . . O X X O . O X O 3 . . O O . . . . |
$$ | . . X O O X O X O 1 . . X X O . . . . |
$$ | . . . X . X X X . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


But at this point it looks like white 12 (or even a) could connect up to the right side group:

Click Here To Show Diagram Code
[go]$$Wm12
$$ -------------------
$$ | . . . . . O O O . O a . . . . . . . . |
$$ | . . O X X O . O . O X 1 . O O . . . . |
$$ | . . X O O X O X O X . . X X O . . . . |
$$ | . . . X . X X X . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]

This post by Shawn Ligocki was liked by: wineandgolover
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Offline Shawn Ligocki
 Post subject: Re: Go by example: Defer capture until forced. Why is this s
Post #2 Posted: Sat Dec 28, 2013 1:21 am 
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I guess black could play the ko instead:

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O 5 X O 7 O X . . . . O O . . . . |
$$ | . . X O O X O X 6 . . . X X O . . . . |
$$ | . . . X . X X . . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


but then even if black wins the ko, he'll have to give up threat to white, maybe the corner even? For example, I could see either:

Click Here To Show Diagram Code
[go]$$B Black wins the ko, but loses the corner.
$$ -------------------
$$ | . . . . 9 O O O X . . . . . . . . . . |
$$ | . . O X X O X O X . . . . O O . . . . |
$$ | . 8 X O O X . X O . . . X X O . . . . |
$$ | . . 0 X . X X . . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


or

Click Here To Show Diagram Code
[go]$$Wm8 Black 11 and 13 elsewhere. \nBlack loses the ko, but gets 2 free moves somewhere.
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O X X O X O X . . . . O O . . . . |
$$ | . 1 X O O X 3 X O . . . X X O . . . . |
$$ | . . 2 X . X X 5 . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


Maybe this is better for black? But not super clear.
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Offline Uberdude
 Post subject: Re: Go by example: Defer capture until forced. Why is this s
Post #3 Posted: Sat Dec 28, 2013 2:26 am 
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You are correct it's not a clear kill of the whole group and requires some more reading. Well done for considering the cut, does the author not? I guess that's the problem when a 5 kyu writes a book using examples from 25 kyus. To answer the question try black 7 as atari to the right of 6 and then defend the cut on the two stones when white captures. White is then locally dead so if black is strong enough in the centre, which seems to be the case but you need to show more of the board to be sure, it's dead.

This post by Uberdude was liked by 4 people: Bill Spight, Bonobo, shapenaji, Shawn Ligocki
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Offline wineandgolover
 Post subject: Re: Go by example: Defer capture until forced. Why is this s
Post #4 Posted: Sat Dec 28, 2013 4:20 am 
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White currently has only a half eye to the left of 9, because black can throw in to deny it. After 11 can he either make two eyes, connect to the right, or get out to the center?

Click Here To Show Diagram Code
[go]$$Bm9
$$ -------------------
$$ | . . . . . O O O X 2 . . . . . . . . . |
$$ | . . O X X O . O X O . . 3 O O . . . . |
$$ | . . X O O X O X O 1 . . X X O . . . . |
$$ | . . . X . X X X . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]

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This post by wineandgolover was liked by: shapenaji
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Offline topazg
 Post subject: Re: Go by example: Defer capture until forced. Why is this s
Post #5 Posted: Sat Dec 28, 2013 4:40 am 
Tengen
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Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O 1 X O . O X . 5 . . O O . . . . |
$$ | . . X O O X O C 2 3 . . X X O . . . . |
$$ | . . . X . X X 4 . X . . . . X O . . . |
$$ | . . . . . . . 6 . . . . . . X O . O . |
$$ | . . X . . . . . 7 . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


This I think is the general gist of Uberdude's point
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Offline Dusk Eagle
 Post subject: Re: Go by example: Defer capture until forced. Why is this s
Post #6 Posted: Sat Dec 28, 2013 12:01 pm 
Gosei
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This is a better way to play:

Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . 1 O O O X . . . . . . . . . . |
$$ | . . O . X O . O X . . . . O O . . . . |
$$ | . 4 X O O X O X . . . . X X O . . . . |
$$ | . 3 2 X . X X . . X . . . . X O . . . |
$$ | . 5 . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]

Now, white can't make two eyes in the corner. Here's an example of a failure for white:

Click Here To Show Diagram Code
[go]$$B 'a' and ;b' are miai, white is dead locally. 8 at 'b' makes no difference either.
$$ -------------------
$$ | . 6 . 8 1 O O O X . . . . . . . . . . |
$$ | 7 . O b X O 9 O X . . . . O O . . . . |
$$ | a 4 X O O X O X . . . . X X O . . . . |
$$ | . 3 2 X . X X . . X . . . . X O . . . |
$$ | . 5 . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


Of course, white can try to break into the center, but all black has to do is save the one stone and black is so strong on the outside that white has no chance to break out or make eyes.

Click Here To Show Diagram Code
[go]$$B Now what?
$$ -------------------
$$ | . . . . 1 O O O X . . . . . . . . . . |
$$ | . . O . X O . O X . . . . O O . . . . |
$$ | . 4 X O O X O X . . . . X X O . . . . |
$$ | . 3 2 X 6 X X . . X . . . . X O . . . |
$$ | . 5 . 7 . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]

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Offline shapenaji
 Post subject: Re: Go by example: Defer capture until forced. Why is this s
Post #7 Posted: Sat Dec 28, 2013 4:35 pm 
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wineandgolover wrote:
White currently has only a half eye to the left of 9, because black can throw in to deny it. After 11 can he either make two eyes, connect to the right, or get out to the center?

Click Here To Show Diagram Code
[go]$$Bm9
$$ -------------------
$$ | . . . . . O O O X 2 . . . . . . . . . |
$$ | . . O X X O . O X O . . 3 O O . . . . |
$$ | . . X O O X O X O 1 . . X X O . . . . |
$$ | . . . X . X X X . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


So, this sequence is better, I think, than the one Uberdude envisioned, but you need to include how to respond to this:

Click Here To Show Diagram Code
[go]$$W
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O X X O . O X . . . . O O . . . . |
$$ | . . X O O X O X 1 3 . . X X O . . . . |
$$ | . . . X . X X 2 . X . . . . X O . . . |
$$ | . . . . . . . . . . . . . . X O . O . |
$$ | . . X . . . . . . . . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]


Click Here To Show Diagram Code
[go]$$B
$$ -------------------
$$ | . . . . . O O O X . . . . . . . . . . |
$$ | . . O X X O . O X . 2 3 . O O . . . . |
$$ | . . X O O X O X O O 1 5 X X O . . . . |
$$ | . . . X . X X X 6 X 4 . . . X O . . . |
$$ | . . . . . . . . 8 7 . . . . X O . O . |
$$ | . . X . . . . . . 9 . . . . . X O . . |
$$ | . . . . . . . X . . . . . . . X O O O |
$$ | . . X X X . . X O . . . . . . X O X X |[/go]

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Offline EdLee
 Post subject:
Post #8 Posted: Sat Dec 28, 2013 7:13 pm 
Honinbo
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Quote:
Well done for considering the cut, does the author not?
I guess that's the problem when a 5 kyu writes a book using examples from 25 kyus.
This. :shock:
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