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Shusaku's taisha mistake
http://www.lifein19x19.com/viewtopic.php?f=15&t=7844		 Page 1 of 1
Author:  Akura [ Sun Feb 10, 2013 8:31 am ]
Post subject:  Shusaku's taisha mistake
I'm trying to work through Invincible starting with Shusaku's famous 'ear-reddening' game. After his mistake in the taisha joseki in the lower right one of the possible but bad alternatives for Black is the following diagram:

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . O . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . X , X . . . . , . . O O X O O . . |
$$ | . . . . . . . . . . 2 O X X X X O . . |
$$ | . . . . . . . . . . O X . 7 . . 3 4 . |
$$ | . . . . . . . . . . . . 1 . . 5 . 6 . |
$$ ---------------------------------------[/go]


What I'm trying to understand now is, what happens in the lower right if Balck tenukis with :b7:. The best for White I can find is a multi-step ko in his favor and the respective line can be found in the hide tags:

Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . O . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X O . . |
$$ | . . X , X . . . . , . . O O X O O . . |
$$ | . . . . . . . . . . O O X X X X O . . |
$$ | . . . . . . . . . . O X 5 2 . . X O . |
$$ | . . . . . . . . . . 1 3 X . 4 X a O . |
$$ ---------------------------------------[/go]


Next ko after Black defends one eye with a move at 'a'. Black has to ignore three ko threats to make his group live.


So, what's your line for White? Or have I found the best?
Author:  SoDesuNe [ Sun Feb 10, 2013 8:43 am ]
Post subject:  Re: Shusaku's taisha mistake
Your vital point is mine?

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


One-step Ko and Black has no threats this big, I think
Author:  Akura [ Sun Feb 10, 2013 8:54 am ]
Post subject:  Re: Shusaku's taisha mistake
Of course I considered SoDesuNe's :w1: and :b2:, but not :w3:. Thank you!
Furthermore, my multi-step ko seems not so multi anymore...
Author:  OtakuViking [ Mon Feb 11, 2013 2:28 am ]
Post subject:  Re: Shusaku's taisha mistake
The real issue is the white influence. Shusaku wanted to damage it as much as possible otherwise the game would be over even if he lived.
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