Life In 19x19

Hi,

I'm currently studying the Tesuji book by James Davids. This is a tsuemgo to practise the double hane tesuji. This is the solution given:



The important part is that white 10 is necessary in order to bring alive the corner - this allows black to catch white in a loose ladder. That is ok with me. BUT: What if white did defend differently at 6. This is what I mean:



If white runs out instead of defending the corner, I can't kill it. What do I miss?

Thanks

Jörg

Click Here To Show Diagram Code

[go]$$Bcm1 Ko?
$$ --------------------
$$ | . 5 2 . . O . . . .
$$ | 3 O 1 4 . O X X . .
$$ | . X O O O X O X . .
$$ | . X X X X X O . . ,
$$ | . . . . . . O . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

Ko is correct but there is a better ko for Black.

Thanks for all the answers. So black needs to be willing to fight a Ko when playing the double hane in this position.

Gegenzeit wrote:Thanks for all the answers. So black needs to be willing to fight a Ko when playing the double hane in this position.

I think for Black that's a nobrainer. At the beginning White has a group, Black has a wall. At the end, Black has an even thicker group, White has a potentially weak center group and a corner that's only alive in ko - it's a huge positive change! The corner is a good 20 points, so White's more likely to play the living move anyway, as it's a very painful ko to leave, and in which case, Black's thickness is outstanding. Either way, the double hane gives a good outcome for Black.

Ok, thanks again. That explanation was really helpful!

This is what's called a flower-viewing ko for black - if black loses the ko, he doesn't lose much, but if white loses the ko, it's a major loss. Black should be happy to start the ko if white actually allows him to do so.

But kills for sure. No?

Click Here To Show Diagram Code

[go]$$Bcm1
$$ --------------------
$$ | . 4 3 1 5 O 7 . . .
$$ | 6 O . 2 . O X X . .
$$ | . X O O O X O X . .
$$ | . X X X X X O . . ,
$$ | . . . . . . O . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .
$$ | . . . , . . . . . ,[/go]

Click Here To Show Diagram Code

[go]$$Bcm1
$$ --------------------
$$ | 8 7 3 1 6 O . . . .
$$ | 5 O 4 2 . O X X . .
$$ | . X O O O X O X . .
$$ | . X X X X X O . . ,
$$ | . . . . . . O . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .[/go]

@ 7, @ 3

Click Here To Show Diagram Code

[go]$$Bcm1
$$ --------------------
$$ | . 6 3 1 8 O 5 . . .
$$ | 7 O 4 2 . O X X . .
$$ | . X O O O X O X . .
$$ | . X X X X X O . . ,
$$ | . . . . . . O . . .
$$ | . . . . . . . . . .
$$ | . . . . . . . . . .[/go]