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Life/death corner
http://www.lifein19x19.com/viewtopic.php?f=15&t=889
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Author:  Numsgil [ Thu Jun 17, 2010 11:11 am ]
Post subject:  Life/death corner

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


Black to move. Is this black corner dead (or at least, it needs to capture that white group to live)? Everything I try seems refutable with a bit of thought for white's response.

eg:

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

Author:  daniel_the_smith [ Thu Jun 17, 2010 11:49 am ]
Post subject:  Re: Life/death corner

Locally, that is dead.

Author:  DeadTired [ Thu Jun 17, 2010 12:10 pm ]
Post subject:  Re: Life/death corner

daniel_the_smith wrote:
Locally, that is dead.

Have you considered starting at p2?

Author:  daniel_the_smith [ Thu Jun 17, 2010 12:16 pm ]
Post subject:  Re: Life/death corner

DeadTired wrote:
daniel_the_smith wrote:
Locally, that is dead.

Have you considered starting at p2?


Yes, but I misread it. :oops: Seems it should be seki.

Author:  DeadTired [ Thu Jun 17, 2010 12:21 pm ]
Post subject:  Re: Life/death corner

daniel_the_smith wrote:
DeadTired wrote:
daniel_the_smith wrote:
Locally, that is dead.

Have you considered starting at p2?


Yes, but I misread it. :oops: Seems it should be seki.

There also seems to be this ko:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O . X X O O |
$$ . . X O O1. 3 X X |
$$ . . . . . 4 . 2 . . |
$$ --------------------+[/go]

Author:  daniel_the_smith [ Thu Jun 17, 2010 12:26 pm ]
Post subject:  Re: Life/death corner

Ah, yeah, you're right... misread yet again! Too much stuff going on today...

Author:  Numsgil [ Thu Jun 17, 2010 1:15 pm ]
Post subject:  Re: Life/death corner

DeadTired wrote:
There also seems to be this ko:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O . X X O O |
$$ . . X O O 1 . 3 X X |
$$ . . . . . 4 . 2 . . |
$$ --------------------+[/go]


I don't think that works because of this:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O . X X O O |
$$ . . X O O 1 . 3 X X |
$$ . . . . . 5 4 2 6 . |
$$ --------------------+[/go]


edit: ah actually, this would be a seki:

Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O 7 X X O O |
$$ . . X O O 1 . 3 X X |
$$ . . . . . 5 4 2 6 . |
$$ --------------------+[/go]

Author:  Dusk Eagle [ Thu Jun 17, 2010 3:39 pm ]
Post subject:  Re: Life/death corner

Please show me how P2 helps at all:

Click Here To Show Diagram Code
[go]$$Wc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O . X X O O |
$$ . . X O O X . . X X |
$$ . . . . . . 1 . . . |
$$ --------------------+[/go]

It looks dead easily to me.

Author:  prokofiev [ Thu Jun 17, 2010 3:45 pm ]
Post subject:  Re: Life/death corner

Dusk Eagle wrote:
Please show me how P2 helps at all:

Click Here To Show Diagram Code
[go]$$Wc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O . X X O O |
$$ . . X O O X . . X X |
$$ . . . . . . 1 . . . |
$$ --------------------+[/go]

It looks dead easily to me.


My reading:

Click Here To Show Diagram Code
[go]$$Wc
$$ . . . . . . . . . . |
$$ , . . . X . , O . . |
$$ . . . . X O O . . . |
$$ . . . . X X X O . . |
$$ . . . . . X O O . . |
$$ . . . O O O X . O . |
$$ . . . X O . . X O O |
$$ , X . X O . X . X O |
$$ X . . X O . X X O O |
$$ . . X O O X . c X X |
$$ . . . . . 2 1 a b . |
$$ --------------------+[/go]


Now a,b give seki. White c lets black live with points (black b).

Author:  Dusk Eagle [ Thu Jun 17, 2010 3:52 pm ]
Post subject:  Re: Life/death corner

Oh yeah :oops: . I saw :b2: followed by b, but not black's follow-up at 'c' rather than 'a'. I guess I'm desperately out of shape with my tsumego...

Author:  Numsgil [ Thu Jun 17, 2010 3:54 pm ]
Post subject:  Re: Life/death corner

Glad to see this is tricky enough to give others trouble too :P

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