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7k tsumego from a Japanese tsumego book
http://www.lifein19x19.com/viewtopic.php?f=15&t=5775		 Page 1 of 1
Author:  tchan001 [ Sun Apr 01, 2012 10:30 am ]
Post subject:  7k tsumego from a Japanese tsumego book
Click Here To Show Diagram Code
[go]$$Bc
$$ ----------------+
$$ . . . . . . . . |
$$ . O O X . X . . |
$$ . . . O . X X . |
$$ . . O . O X O . |
$$ . . . . O O O . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

Black to move
What is the status of the black group given the optimal sequence of play?
Author:  RBerenguel [ Sun Apr 01, 2012 10:54 am ]
Post subject:  Re: 7k tsumego from a Japanese tsumego book
I see ways for white to kill, but there can always be traps I can't read... I am pretty sure black can kill easily :D
Author:  tj86430 [ Sun Apr 01, 2012 11:32 am ]
Post subject:  Re: 7k tsumego from a Japanese tsumego book
I didn't find a way for black to live.
Author:  karaklis [ Sun Apr 01, 2012 11:33 am ]
Post subject:  Re: 7k tsumego from a Japanese tsumego book
Nice problem.
I cannot see that w can do anything after b p19. If w tries to make ko or seki, then this happens:
Click Here To Show Diagram Code
[go]$$Bc
$$ ----------------+
$$ . . . 1 . 7 4 . |
$$ . O O X 6 X 5 2 |
$$ . . . O . X X 3 |
$$ . . O . O X O . |
$$ . . . . O O O . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

Black lives by oshitsubushi


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

again oshitsubushi


Well, obviously I got it wrong. Never mind. ;-)
Author:  Wildclaw [ Sun Apr 01, 2012 2:16 pm ]
Post subject:  Re: 7k tsumego from a Japanese tsumego book
tchan001 wrote:
What is the status of the black group given the optimal sequence of play?


I am a bit out of shape, but I think the optimal sequence goes like this.

Click Here To Show Diagram Code
[go]$$Bc
$$ ----------------+
$$ . . 6 1 7 3 2 . |
$$ . O O X 4 X . 8 |
$$ . . . O 5 X X 9 |
$$ . . O . O X O 0 |
$$ . . . . O O O . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

1. Standard way to live with this shape by expanding eye space
2. Key move aiming to remove the Q18 eye
3. Only way for black to protect
4. But now white has time to throw in
5-7. Black has no choice but to capture
8-0. Giving white the opportunity to fill all the outside liberties.
Author:  tchan001 [ Sun Apr 01, 2012 6:06 pm ]
Post subject:  Re: 7k tsumego from a Japanese tsumego book
Good job Wildclaw. Actually the book solution ends with 3 and says something about Black living (althought it doesn't have the word seki anywhere in the explanation), but the sequence you have is the one I arrived at as well.
Author:  Bill Spight [ Sun Apr 01, 2012 8:34 pm ]
Post subject:  Re: 7k tsumego from a Japanese tsumego book
Wildclaw wrote:
tchan001 wrote:
What is the status of the black group given the optimal sequence of play?


I am a bit out of shape, but I think the optimal sequence goes like this.

Click Here To Show Diagram Code
[go]$$Bc
$$ ----------------+
$$ . . 6 1 7 3 2 . |
$$ . O O X 4 X . 8 |
$$ . . . O 5 X X 9 |
$$ . . O . O X O 0 |
$$ . . . . O O O . |
$$ . . . . . . . . |
$$ . . . . . . . . |[/go]

1. Standard way to live with this shape by expanding eye space
2. Key move aiming to remove the Q18 eye
3. Only way for black to protect
4. But now white has time to throw in
5-7. Black has no choice but to capture
8-0. Giving white the opportunity to fill all the outside liberties.


White can usually omit :w10:, as it is gote. :) He can also probably save :w2: as a potential ko threat.
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