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KanazawaProblem12

 

Kanazawa Solution 12
Path: KanazawaSolutions   · Prev: KanazawaSolution11   · Next: KanazawaSolution13
    Keywords: Problem

[Diagram]
Diag.: White lives

There is absolutely no time to expand the eyespace. White has to play at the vital point right now. And the vital point of this shape is 1.


[Diagram]
Diag.: Continuation

The points 2 and 3 are miai and after the 2-3 exchange, a and b are miai.


[Diagram]
Diag.: Why the vital point ?

The reason that 1 is the vital point lies in the fact that White can answer the atari of Black 2 with White 3. Without 1 in place, Black would capture three stones.



[Diagram]
Diag.: Wrong

As said before, expanding the eyespace is not right. Black plays atari at 2 and after White 5, Black can start a ko with 6 at 2. Life in ko is not sufficient.



[Diagram]
Diag.: Wrong (ii)

This shape does not call for the 1-2 point. The points a and b are miai to keep White down to one eye, and Black destroys the other eye by playing 2. Playing 2 at b also works. Black should not play the atari as in the previous diagram, because that permits ko. In fact, White 1 destroys more eyeshape than it makes and she dies unconditionally.



[Diagram]
Diag.: Wrong (iii)

White 1 here is basically the same mistake as the first one.



[Diagram]
Diag.: Wrong (iv)

Finally, the other 1-2 point leads to the same ko result once again.



[Diagram]
Diag.: Wrong (iv) without ko

It seems to me that in this last diagram, Black can kill unconditionally, without a ko. After Black 4, White cannot make a second eye due to damezumari.

This also goes for the third wrong solution (wrong iii), where after White at b, Black exchanges a for 1 to get the same situation.



Problem 13
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