Life In 19x19

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[go]$$Bm1
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$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . 3 . 2 . . . . .|
$$ | . . . , . . . . . 8 6 . 7 b . 1 . . .|
$$ | . . . . . . . . . . . . a 4 . . . . .|
$$ | . . . . . . . . . . . . . . . 5 . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

What is the refutation of B7 ?

a-b doesn't seem satisfactory...

Tryphon wrote:

$$Bm1
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$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . 3 . 2 . . . . .|
$$ | . . . , . . . . . . 6 . 7 b . 1 . . .|
$$ | . . . . . . . . . . . . a 4 . . . . .|
$$ | . . . . . . . . . . . . . . . 5 . . .|
$$ | . . . . . . . . . . . . . . . . . . .|

Click Here To Show Diagram Code

[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . 3 . 2 . . . . .|
$$ | . . . , . . . . . . 6 . 7 b . 1 . . .|
$$ | . . . . . . . . . . . . a 4 . . . . .|
$$ | . . . . . . . . . . . . . . . 5 . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

What is the refutation of B7 ?

a-b doesn't seem satisfactory...

(In the following, I assume that your 8 should not be there.)

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[go]$$Wm1
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$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . B . W . . . . .|
$$ | . . . , . . . . . . W . B 1 . B . . .|
$$ | . . . . . . . . . . . 4 2 W . . . . .|
$$ | . . . . . . . . . . . . 3 . . B . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

I think 1 is more than satisfactory. White forces black into bad shape. I'm not sure what's best next, but...

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[go]$$Wm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . a B . W . . . . .|
$$ | . . . , . . . . . . W . B W . B . . .|
$$ | . . . . . . . . . . . B B W . . . . .|
$$ | . . . . . . . . . . . . W . . B . . .|
$$ | . . . . . . . . . . . . . W . . . . .|[/go]

With something like this, white makes a strong shape and is now seriously threatening the black stones on the right. Black's empty triangle group is also in bad shape, with a white stone on its perfect shape point, and so is ripe for attacking. I'm not sure where black can play now, white moves like a will destroy his shape even more, but black taking a himself pushes from behind in gote.


I think this general idea is good for white, but I may be wrong about elements of the implementation. In particular, it may be a good idea for white to play a earlier (it is sente, but if white then sacrifices those stones quickly it would be wasted), and the tigers mouth connection might be better played differently.

IMHO, this is the only reasonable reply. Otherwise 9 at 8 decimates black.
Whether or not it constitutes a refutation, I cannot say. But the fact the joseki books do not even mention 7 suggest that 8 is indeed a refutation.

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[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . 3 . 2 . . . . .|
$$ | . . . , . . . . . . 6 . 7 8 . 1 . . .|
$$ | . . . . . . . . . . . . . 4 . . . . .|
$$ | . . . . . . . . . . . . . . . 5 . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

Also, Amnal's analysis seems persuasive.

yeah, just connecting is good enough

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[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . a X . O . c d . .|
$$ | . . . , . . . . . . O . X O . X . . .|
$$ | . . . . . . . . . . . . b O . . . . .|
$$ | . . . . . . . . . . . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

"a" and "b" are really the only options here

both let black live, but the important thing here is now black has made "c" and "d" much more powerful than they would have been otherwise

"a" can get a bit complicated, but simply coming over top should be enough

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[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . 1 X . O . . . . .|
$$ | . . . , . . . . 5 3 O . X O . X . . .|
$$ | . . . . . . . . . 4 . . 2 O . . . . .|
$$ | . . . . . . . . . . . . . . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

And now white can attack the right side very strongly

On the other hand, if "b", the sequence amnal pointed out shows they get terrible shape
If they attempt to resist, it can get complicated though

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[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . 5 X . O . . . . .|
$$ | . . . , . . . . . . O . X O . X . . .|
$$ | . . . . . . . . . . . 4 1 O . . . . .|
$$ | . . . . . . . . . . 6 3 2 . . X . . .|
$$ | . . . . . . . . . . . 7 . 8 . . . . .|[/go]

This is one way it could play out. The important thing to remember is that by pushing you this way, black's corner is going up for grabs

Thanks to the 3 of you

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[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . 4 X . O . . . . .|
$$ | . . . , . . . . . . O . X O . X . . .|
$$ | . . . . . . . . . . . . 1 O . . . . .|
$$ | . . . . . . . . . . . 3 2 . . X . . .|
$$ | . . . . . . . . . . . . . . . . . . .|[/go]

If black descends after 4, he will get cut and die. if he does not descend, the result is terrible for black in many ways and white has achieved perfect safety. The corner is weaker, as Shape said, and whether you bother playing 2 or not, it's kind of the same. As long as you don't allow black a solid connection to the corner, for example, black 2 and another black move to the right of 2, then black is very bad. Even if he spends many moves connecting, then he's bad i nthat respect, as his (1) group does not do anything. Just bad.

Click Here To Show Diagram Code

[go]$$Bm1
$$ +--------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . . . . . . . . . .|
$$ | . . . . . . . . . . 5 X . O . . . . .|
$$ | . . . , . . . . . . O . X O . X . . .|
$$ | . . . . . . . . . . . 4 1 O . . . . .|
$$ | . . . . . . . . . . 6 3 2 . . X . . .|
$$ | . . . . . . . . . . . 7 . 8 . . . . .|[/go]

I think white 4 would be a mistake here, though white 8 is a big gain so white seems still okay, but...! Although it can be complicated, if you can put 8 to the left of 7, you might be able to find time to Play a Hane to the left of 5 and have enough liberties in the center to double hane and capture some important black stones.

If Black 3 at 4, white can play 5 and after black descends at the top, white can seal it all off with a knight's move below 6. Black is short liberties and will die.

After exchanging for 2, black still has time to play 5, so white 5 after black 1 is another idea.