Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

SoDesuNe · Post by **SoDesuNe** » Thu Sep 29, 2011 5:49 am

This book is giving me quite a hard time because it seems that without being able to read the chinese characters, some problems - especially the answers - are very hard to understand (for me).

One example, which I discussed with a local Dan-player was the following:

Click Here To Show Diagram Code: [go]$$Bc Problem $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . . . . . $$ | . . . . . . X W . . . $$ | . O . X . X O . . , X $$ | . O X . . X O . O . X $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

It's Black to move and there seems to be a very obvious candidate.

Click Here To Show Diagram Code: [go]$$Bc Obvious move? $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . 1 . . . $$ | . . . . . . X O 2 . . $$ | . O . X . X O . . , X $$ | . O X . . X O . O . X $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

But according to the answer this is inferior.

Click Here To Show Diagram Code: [go]$$Bc Book's answer $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . . . . . $$ | . . . . . . X O . . . $$ | . O . X . X O 1 . , X $$ | . O X . . X O . O . X $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

This is the answer. But the local Dan-player said, he would never play this move and that it looks crude. White could even sacrifice his two stones and making a strong shape in the center.

The book's complete answer has two diagrammes:

1.

Click Here To Show Diagram Code: [go]$$Bc Complete book's answer 1 $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . 3 . . . $$ | . . . . . . X O 4 . . $$ | . O . X . X O 1 2 , X $$ | . O X . . X O 6 O . X $$ | . . . . . . 5 . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

2.

Click Here To Show Diagram Code: [go]$$Bc Complete book's answer 2 $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . 3 . . . $$ | . . . . . . X O . 5 . $$ | . O . X . X O 1 2 , X $$ | . O X . . X O 4 O . X $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

And both seem good for Black, I think.

Furthermore there is this diagramme, pointing out, that after the :b1:

-

-exchange, Black cannot play :b3:

anymore.

Click Here To Show Diagram Code: [go]$$Bc Book's failure diagramme $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . 1 . . . $$ | . . . . . . X O 2 . . $$ | . O . X . X O 3 . , X $$ | . O X . . X O . O . X $$ | . . . . . . 4 . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

This is what the local Dan-player suggested, when Black cuts...

Click Here To Show Diagram Code: [go]$$Bc 3D's answer $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X 6 . . . . $$ | . . . . . 7 X O 2 . . $$ | . O . X . X O 1 8 , X $$ | . O X . . X O 3 O . X $$ | . . . . . 9 4 5 0 . . $$ | . . . . . . . . . . . $$ ------------------[/go]

Click Here To Show Diagram Code: [go]$$Bcm11 3D's answer $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X O . . . . $$ | . . . . . X X O O . . $$ | . O . X . X W X O , X $$ | . O X . . X W X O . X $$ | . . . . . X W X O . . $$ | . . . . . . 1 . . . . $$ ------------------[/go]

...and I don't find this bad for White. Of course it's hard to measure the result in this local context because we don't know how much support the two Black stones on the right have.

But then again, how and when is :b1:

in the book's answer a Tesuji?

amnal · Post by **amnal** » Thu Sep 29, 2011 6:33 am

But then again, how and when is in the book's answer a Tesuji?

I think the answer is quite simple; :b1:

is a tesuji when all of the variations you suggested are good for black. Checking all the possibilities is really the only way to verify it.

I think the real point of the book's author is that :b1:

allows white to get both hanes in sente. That's what he wants you to think about and understand the possibility of. It is not the case that this move will always be the best, but it's probably impossible to find a tesuji that this is not true of. Also, it seems reasonable to assume that black's two stones on the right are strong in the context of the problem.

Magicwand · Post by **Magicwand** » Thu Sep 29, 2011 6:51 am

Click Here To Show Diagram Code: [go]$$Bc 3D's answer $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . 7 . . . . $$ | . . O . . X 2 . . . . $$ | . . . . . 3 X O 4 . . $$ | . O . X . X O 1 . , X $$ | . O X . . X O 6 O . X $$ | . . . . . . 5 . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

this is what i expect...
some variations in the book are not what you expect strong players to play.

IMO, cutting seems only optimal move.
rest depends on the board situation...

gaius · Post by **gaius** » Thu Sep 29, 2011 7:08 am

My first thought was also "wow, that cut looks crude". But I changed my mind. Getting both hanes is nice indeed. I would not have found this in a game, I think.

Check this tewari. In diagramme II (after the book's cut), :w4:

looks badly placed. So perhaps the cut is a good tesuji indeed. Maybe the author of this book was not so stupid after all

Click Here To Show Diagram Code: [go]$$Bc Tewari I: the "obvious" variation $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X . 1 3 . . $$ | . . . . . . X O 2 4 . $$ | . O . X . X O 7 . , X $$ | . O X . . X O 8 O . X $$ | . . . . . . 5 6 . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

Click Here To Show Diagram Code: [go]$$Bc Tewari II: cut first. $$ | . . . , . . . . . . . $$ | . . O . . . . . . . . $$ | . . . . . . . . . . . $$ | . . . . . . . . . . . $$ | . . O . . X 2 5 9 . . $$ | . . . . . 3 X O 6 0 . $$ | . O . X . X O 1 4 , X $$ | . O X . . X O 8 O . X $$ | . . . . . . 7 . . . . $$ | . . . . . . . . . . . $$ ------------------[/go]

Website · Post by **Chew Terr** » Mon Oct 03, 2011 7:50 am

Where can I find these books? It's not the same as this, is it? http://www.amazon.com/Lee-Chang-Hos-Lif ... 2&sr=1-133

SoDesuNe · Post by **SoDesuNe** » Mon Oct 03, 2011 10:26 am

No, those are the Life-and-Death ones. There are corresponding Tesuji books.

http://senseis.xmp.net/?LiChangHoJingjiangWeiqiShoujin

You can buy them (e.g.) on http://mohsart.se.

gogameguru · Post by **gogameguru** » Mon Oct 10, 2011 12:12 am

It really depends on the strength of those two black stones on the right hand side of the diagram, and you should take into account that that's a slightly unusual shape.

If those two stones are strong, sacrificing just loses eye shape and makes a heavy group for white (thick groups are just heavy sometimes).

It also makes black's group completely alive, which makes it even easier for black to attack white's 'stick'.

On the other hand, if sacrificing was a good strategy, then skipping the cut like you suggest would probably be better.

It's awhile since I've read those books, but I remember that I didn't get this problem right the first time either.

Life In 19x19

Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Re: Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Re: Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Re: Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Re: Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Re: Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3

Re: Problem 2.6 of Yi Ch'ang-Ho's Tesuji Problems Vol. 3