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Help with a tsumego please
Posted: Sat Nov 19, 2011 4:32 am
by Gegenzeit
Hi,
I came across this tsumego today (white to kill):
http://www.lifein19x19.com/forum/download/file.php?id=1347
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:
http://www.lifein19x19.com/forum/download/file.php?id=1350
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.
http://www.lifein19x19.com/forum/download/file.php?id=1351
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

Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 4:43 am
by Li Kao

looks wrong. Black answers at g18 and lives.

at J19 on the other hand looks like it works.
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 4:51 am
by Gegenzeit
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

...
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 4:53 am
by Cassandra
In my opinion, White G19 is the very vital point.
Black dies, whenever White plays it. There will be no Ko.
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 6:07 am
by Gegenzeit
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.
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 6:15 am
by Cassandra
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.
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 7:22 am
by Gegenzeit
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

Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 8:05 am
by Cassandra
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:
$$
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$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . O X . X . X X O . O . . . . . . . |
$$ | . . O O X X X O O . O . . . . . . . . |
$$ | . . . O O O O O . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
- 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]
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 11:01 am
by Gegenzeit
that might be it. On the first glance it really looks pretty much the same.
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 1:41 pm
by Cassandra
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.
Re: Help with a tsumego please
Posted: Sat Nov 19, 2011 2:11 pm
by Magicwand
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
Re: Help with a tsumego please
Posted: Sun Nov 20, 2011 1:13 am
by Cassandra
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.