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Help with a tsumego please
http://www.lifein19x19.com/viewtopic.php?f=11&t=5007		 Page 1 of 1
Author:  Gegenzeit [ Sat Nov 19, 2011 4:32 am ]
Post subject:  Help with a tsumego please
Hi,

I came across this tsumego today (white to kill):



I thought I had figured out 2 ways to kill black and went to the solutions. But alas, according to my book one of my solutions is wrong:



White starts a ko with 3 and if black wins, the group is alive. My problem is that I do not see why white should bother to answer 2 by taking the ko.
If white just plays the vital point of the group, black still has to look for a second eye - and all eyes I can find are false ones.



I tried other variations - but all had in common that black is unable to connect // has only one real eye.

Can anyone else find black a second eye?


Thanks

Jörg

PS: I am aware that playing the vital point directly is probably more elegant ;)

Attachments:
looking for an eye_1.sgf [197 Bytes]
Downloaded 600 times
what the book says_1.sgf [160 Bytes]
Downloaded 574 times
starting position.sgf [120 Bytes]
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Author:  Li Kao [ Sat Nov 19, 2011 4:43 am ]
Post subject:  Re: Help with a tsumego please
:w5: looks wrong. Black answers at g18 and lives.

:w5: at J19 on the other hand looks like it works.
Author:  Gegenzeit [ Sat Nov 19, 2011 4:51 am ]
Post subject:  Re: Help with a tsumego please
Ah .. I believed 5 to work because I can build a 3 stones "dead" nakade with H19 in reaction to G18. I didn't see that it won't work in that case. Interesting!

Anyone sees a way to deal with 5 on J19 ;)

...
Author:  Cassandra [ Sat Nov 19, 2011 4:53 am ]
Post subject:  Re: Help with a tsumego please
In my opinion, White G19 is the very vital point.

Black dies, whenever White plays it. There will be no Ko.
Author:  Gegenzeit [ Sat Nov 19, 2011 6:07 am ]
Post subject:  Re: Help with a tsumego please
Cassandra wrote:
In my opinion, White G19 is the very vital point.

Black dies, whenever White plays it. There will be no Ko.



You're right! Sorry for not making it clearer in the first post.

The questions is whether White 1 on D19 also kills. It appears as if it does.
Author:  Cassandra [ Sat Nov 19, 2011 6:15 am ]
Post subject:  Re: Help with a tsumego please
Gegenzeit wrote:
The questions is whether White 1 on D19 also kills. It appears as if it does.

True. But White must follow this Hane with G19 as move 3 anyway.

It White captures on the left instead (and never intends to play at G19), it will arise an approach-move Ko.
Author:  Gegenzeit [ Sat Nov 19, 2011 7:22 am ]
Post subject:  Re: Help with a tsumego please
G19 sure is more elegant! I was just confused, because the book I study with rules the hane out. According to the book the Ko is the only way after white 2 on e19.

Lesson of the day: Books are not infallible ;)
Author:  Cassandra [ Sat Nov 19, 2011 8:05 am ]
Post subject:  Re: Help with a tsumego please
Gegenzeit wrote:
G19 sure is more elegant! I was just confused, because the book I study with rules the hane out. According to the book the Ko is the only way after white 2 on e19.

Lesson of the day: Books are not infallible ;)

Perhaps they mixed it up with the following Tsume-Go:

Click Here To Show Diagram Code
[go]$$
$$ ---------------------------------------
$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . O X . X . X X O . O . . . . . . . |
$$ | . . O O X X X O O . O . . . . . . . . |
$$ | . . . O O O O O . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]
Author:  Gegenzeit [ Sat Nov 19, 2011 11:01 am ]
Post subject:  Re: Help with a tsumego please
that might be it. On the first glance it really looks pretty much the same.
Author:  Cassandra [ Sat Nov 19, 2011 1:41 pm ]
Post subject:  Re: Help with a tsumego please
Gegenzeit wrote:
that might be it. On the first glance it really looks pretty much the same.

A Hane on the first line often makes the decisive difference.
Author:  Magicwand [ Sat Nov 19, 2011 2:11 pm ]
Post subject:  Re: Help with a tsumego please
Cassandra wrote:
Gegenzeit wrote:
that might be it. On the first glance it really looks pretty much the same.

A Hane on the first line often makes the decisive difference.

but not this one..
IMO g19 kills black same way
Author:  Cassandra [ Sun Nov 20, 2011 1:13 am ]
Post subject:  Re: Help with a tsumego please
Magicwand wrote:
Cassandra wrote:
Gegenzeit wrote:
that might be it. On the first glance it really looks pretty much the same.

A Hane on the first line often makes the decisive difference.

but not this one..
IMO g19 kills black same way

Yes, indeed.

However, the incorrect variation (White D19) ends in Ko now, as Gegenzeit's book told him for the problem without the Hane on the right.
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