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Problem of the day ( 1K - 5K ) - Sept 19th, 2010

https://lifein19x19.com/viewtopic.php?t=1686

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Problem of the day ( 1K - 5K ) - Sept 19th, 2010

Posted: Sun Sep 19, 2010 8:56 pm
by Joaz Banbeck
Problems from the Cotsen tournament, for all of you who could not make it:

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | . O . X X X . . . . . . .
$$ | . . X O O . X . . . . . .
$$ | . . O . O X . . . . . . .
$$ | . . . . . . . . . . . . .
$$ |--------------------------[/go]

Re: Problem of the day ( 1K - 5K ) - Sept 19th, 2010

Posted: Sun Sep 19, 2010 10:15 pm
by Chew Terr
Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | . O 2 X X X . . . . . . .
$$ | . 1 X O O . X . . . . . .
$$ | . 3 O . O X . . . . . . .
$$ | . . . . . . . . . . . . .
$$ |--------------------------[/go]

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

Here's my attempt. Am I missing something? Wait, saw what I was missing.
Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | . O 4 X X X . . . . . . .
$$ | 5 1 X O O . X . . . . . .
$$ | 3 2 O . O X . . . . . . .
$$ | b 6 . a . . . . . . . . .
$$ |--------------------------[/go]

'a' doesn't work because of 'b', so white lives below. Maybe I'll be able to see it in the morning.

Re: Problem of the day ( 1K - 5K ) - Sept 19th, 2010

Posted: Mon Sep 20, 2010 12:50 am
by entropi
Since this is presented as a problem, the initial move should be something fancy :)
What about this:

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | . O 4 X X X . . . . . . .
$$ | . 2 X O O . X . . . . . .
$$ | . 1 O b O X . . . . . . .
$$ | . . 3 a 5 . . . . . . . .
$$ |--------------------------[/go]

ko at a-b?

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



or

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

Re: Problem of the day ( 1K - 5K ) - Sept 19th, 2010

Posted: Mon Sep 20, 2010 7:22 am
by Kirby
Chew Terr wrote:
...
Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | . O 4 X X X . . . . . . .
$$ | 5 1 X O O . X . . . . . .
$$ | 3 2 O . O X . . . . . . .
$$ | b 6 . a . . . . . . . . .
$$ |--------------------------[/go]

'a' doesn't work because of 'b', so white lives below. ...


Are you sure?

Re: Problem of the day ( 1K - 5K ) - Sept 19th, 2010

Posted: Mon Sep 20, 2010 7:32 am
by Chew Terr
Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | . O 4 X X X . . . . . . .
$$ | 5 1 X O O . X . . . . . .
$$ | 3 2 O . O X . . . . . . .
$$ | b 6 . a . . . . . . . . .
$$ |--------------------------[/go]

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . . . . . . . . . . . . .
$$ | . X X . . . . . . . . . .
$$ | . O X . . . . . . . . . .
$$ | 4 O O X X X . . . . . . .
$$ | a C b O O . X . . . . . .
$$ | C O O 3 O X . . . . . . .
$$ | 2 O . 1 5 . . . . . . . .
$$ |--------------------------[/go]

a and b are miai to kill, I think. Thanks, Kirby![/

Re: Problem of the day ( 1K - 5K ) - Sept 19th, 2010

Posted: Mon Sep 20, 2010 7:40 am
by Kirby
Chew Terr wrote:
...Thanks, Kirby!



Actually, I made the first mistake when I first approached this problem. I read the same sequence as you did, and thought that "a" did not work.
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