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can this black group be captured?

Posted: Tue Aug 27, 2013 11:03 pm
by cherryhill
in the game i played 2 because my reading skills aren't good enough to even try to read that problem out in a game unless i want to lose on time before i had finally read out the problem. but during a review i was told that i was giving up too much territory in exchange for the thickness which made W6 too important to lose and so i should have played 1. but in trying to play this out on the board, i cannot see how to kill this group if black descends, at least not simply. like maybe if i cause more trouble in the corner but at that point the tree becomes so big and varied it is hard for me to accurately figure out how black would respond. it just seems like white is short a liberty in this race


Re: can this black group be captured?

Posted: Wed Aug 28, 2013 12:58 am
by Bill Spight
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . X O 1 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
It does not take much in the way of reading to see that :w1: is a good play. If White loses a fight with the four Black stones, it can be a good sacrifice. Each side has four dame, so that it is possible that Black will have to capture the White stones, not just kill them. Also, as you point out, White threatens to enter the bottom right corner. If you waited until you can read everything out, you would never make a play.

Re: can this black group be captured?

Posted: Wed Aug 28, 2013 1:30 am
by HermanHiddema
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X 2 . |
$$ | . . . . . . . . . . . . . a 4 X O 1 . |
$$ | . . . . . . . . . . . . . c 5 3 b . . |
$$ | . . X , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
If Black plays :b2:, white can break out with :w3: and :w5:. Now, white threatens a ladder at a, so black cannot cut at b or play hane at c.
Click Here To Show Diagram Code
[go]$$Bm6
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . 4 5 . |
$$ | . . . . . . . . . . . . . . . . O 3 . |
$$ | . . . , . . . . . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . 1 B B O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X 2 . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
If black extends to :b6:, white takes the corner with :w7:. This is a disaster for black. Black can live with :b8:, but white took the corner and is still strong on the outside, and black's marked stones are heavy and floating.

Re: can this black group be captured?

Posted: Wed Aug 28, 2013 5:18 am
by ez4u
Normally the joseki proceeds with :w1: below instead of :w3: first. This is the only example of Black descending at :b2: in GoGoD. White cuts at :w3: and things end peacefully.
Click Here To Show Diagram Code
[go]$$Wc Yi Tong-kyu (White) - Cho Hun-hyeon, 3rd BC Card Cup 1993-01-15
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 8 . . . O . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . O . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . O . . . . . . . . . . . . O O . |
$$ | . . . . . 6 . . . . . . . . . X . . . |
$$ | . . . O 7 3 X X X X . . . . . X O . . |
$$ | . . . . 1 X O O O O X . . . . X O . . |
$$ | . . . . 5 2 . . . . 4 . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
All other professional games in GoGoD follow the pattern of the connection at :b1: below. After :w2:, Black exchanges :b3: for :w4:. After this Black has the option of stirring things up in the lower left with "a", but only at the cost of letting White play "b". Most often play turns elsewhere. Both sides will be trying to see whether they can make "a" or "b" more important.
Click Here To Show Diagram Code
[go]$$Bc Chen Yaoye (White) - Zhou Ruiyang, 19th Mingren 2006-06-27
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . 1 X X X X . . . . . O . . . |
$$ | . . . . O X O O O O X . . X . 6 5 . . |
$$ | . . . a 3 2 . . . . b . . . . . . . . |
$$ | . . . . . . 4 . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
So refuting the OP cut at the marked stone requires something else. My first reaction is the atari and connection at :w1: and :w3:. What happens after the exchange of :b4: for :w5:?
Click Here To Show Diagram Code
[go]$$Wc What happens next?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . 2 B O . . |
$$ | . . . . . . . . . . . . . . 4 1 3 . . |
$$ | . . X , . . . . . , . . . . . X 5 . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: can this black group be captured?

Posted: Wed Aug 28, 2013 7:50 am
by Kirby
Herman:

I kind of agree with what you wrote, but do you think that white's influence is deterred a bit if black plays here next:
Click Here To Show Diagram Code
[go]$$Bm6
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . 4 5 . |
$$ | . . . . . . . . . . . . . . . . O 3 . |
$$ | . . . , . . . . . , . . . . . W X . . |
$$ | . . . . . . . . . . . . . . . W X . . |
$$ | . . . . . . . . . . . . . . . W X . . |
$$ | . . . . . . . . . . . . . . . W X X . |
$$ | . . . . . . . . . . . . . 1 X X O O . |
$$ | . . . . . . . . . . . . . 7 O O . . . |
$$ | . . X , . . . . . , . . . . . X 2 . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Black's corner still got destroyed, and white is probably happy, but the effect of white's wall seems reduced, and black's stones are not really floating, now.

Perhaps it's enough that white has more than b here, but I get a slight feeling that the marked stones above are not optimally efficient.

Re: can this black group be captured?

Posted: Wed Aug 28, 2013 9:08 am
by HermanHiddema
@Kirby: Yeah, I tried to keep it simple, but there are always complexities. Personally, I think I would actually play double hane with :w9: :)

Re: can this black group be captured?

Posted: Wed Aug 28, 2013 9:46 am
by Kirby
Okay. In any case, it looks like white can get a satisfactory result, which I suppose is helpful.

I guess with the double hane, white can get sente if black tries to live inside, so if white wanted to, he could use this to push against those floating stones:
Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 3 1 . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . , . . . . . , . . . . . O X . 2 |
$$ | . . . . . . . . . . . . . . . O X 4 . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . 5 O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Maybe if black cuts the double hane, he can still get sente or have ladder aji, but it's a lot to give white, I guess. But it's not clear to me which of the marked points white would play next:
Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . . . C 2 1 . |
$$ | . . . . . . . . . . . . . . . 3 O X . |
$$ | . . . , . . . . . , . . . . . O X . 4 |
$$ | . . . . . . . . . . . . . . . O X 6 . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . C O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
Sacrificing the black stones on the side seems unreasonable, so even with double hane, maybe it's not worth discussing...

So I wonder which is better for white between:
Click Here To Show Diagram Code
[go]$$Bm1 White Sente
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . X O . |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . . , . . . . . , . . . . . O X . X |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
This (if white forces a sacrifice from double hane):
Click Here To Show Diagram Code
[go]$$Bm1 White Sente
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . 5 . |
$$ | . . . . . . . . . . . . . . . . 1 . 7 |
$$ | . . . . . . . . . . . . . . . 2 O X . |
$$ | . . . , . . . . . , . . . . . O X 6 3 |
$$ | . . . . . . . . . . . . . . . O X 4 . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X 8 |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This:
Click Here To Show Diagram Code
[go]$$Bm1 Black Sente
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . , . . . . . , . . . . . O X . X |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


and ez4u's diagram:
Click Here To Show Diagram Code
[go]$$Wc $$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . X X O . . |
$$ | . . . . . . . . . . . . . . X O O . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: can this black group be captured?

Posted: Wed Aug 28, 2013 9:54 am
by Kirby
Thinking about it more, I think the double-hane is pretty good as white can force black to take the outside, even in this variation:
Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . 1 . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . , . . . . . , . . . . . O X . 2 |
$$ | . . . . . . . . . . . . . . . O X 3 . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
If black does take the stone, it can come to this:
Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . 6 . |
$$ | . . . . . . . . . . . . . . . . 4 1 8 |
$$ | . . . . . . . . . . . . . . . 5 O X . |
$$ | . . . , . . . . . , . . . . . O X 7 2 |
$$ | . . . . . . . . . . . . . . . O X 3 . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X 9 |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
But in this case, is it something white should do? What is better here? The influence white has from this:

Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . , . . . . . , . . . . . O X . X |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
or this:
Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . X . X |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . . , . . . . . , . . . . . O X O X |
$$ | . . . . . . . . . . . . . . . O X O . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X O |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: can this black group be captured?

Posted: Sun Sep 15, 2013 7:24 am
by tynan
I think the question is whether or not white still has the corner in the second diagram. If he does, then the death of 5 black stones makes white position very powerful in this section of the board.
Kirby wrote: But in this case, is it something white should do? What is better here? The influence white has from this:

Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O O . |
$$ | . . . . . . . . . . . . . . . . O X . |
$$ | . . . , . . . . . , . . . . . O X . X |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]
or this:
Click Here To Show Diagram Code
[go]$$Wm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . X . |
$$ | . . . . . . . . . . . . . . . . X . X |
$$ | . . . . . . . . . . . . . . . O O X . |
$$ | . . . , . . . . . , . . . . . O X O X |
$$ | . . . . . . . . . . . . . . . O X O . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X X O |
$$ | . . . . . . . . . . . . . X X X O O . |
$$ | . . . . . . . . . . . . . . O O . . . |
$$ | . . X , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . X . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]