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KanazawaProblemThree

 

Kanazawa Solution Three
Path: KanazawaSolutions   · Prev: KanazawaSolutionTwo   · Next: KanazawaSolutionFour
    Keywords: Problem

Authors:

Main line: HashimotoUtaro 9p
Variations: AndreEngels 3D, unkx80 1D*, DieterVerhofstadt 1k


[Diagram]
Main line

After 1, making an eye at the circled point, a and b are miai for life.


[Diagram]
2 and 3 are miai (i)

After 3, Black has real eyes at the circled points.


[Diagram]
2 and 3 are miai (ii)

It seems as if White 2 makes the eye false, but the capture of three stones with 5 results in a real eye.


[Diagram]
2 and 3 are miai (ii cont)

Even if white throws in at 6, Black lives with 7.



[Diagram]
Variation

If White captures at 2, Black 3 makes a second eye. If Black doesn't respond, White a kills the group.



[Diagram]
Wrong (i)

The other 1-2 point is again not successful. With 2, Black is left on the spot. Even if allowed to play two moves in a row, he can't live any more.



[Diagram]
Wrong (ii)

When Black plays 1 here, White can choose between a and b to kill Black. Someone with an opinion which is the better ?


[Diagram]
White kills at 'a'

We must look at the ko threats black has. Here black can make two eyes by playing both 'a' and 'b', so either of them can be used as a ko threat. However, this is the only threat black can have from this position.


[Diagram]
White kills at 'b'

Here black will again live by having both 'a' and 'b', so they are both ko threats. Again, no more threats for black. So, are the moves equal?


[Diagram]
White ignores threat of 'a'

Let's say the ko was crucial enough that white had to ignore this threat. Can white have ko threats of her own to kill black again, if another big ko appears in the game? W1 is the best she can do, threatening to make a ko for black's life at 'a'.


[Diagram]
White ignores threat at 'b'

Here, however, white can make a threat to kill the black group without a ko (by filling at BC). 'a' is still playable, for the ko would be a hanami ko for white. Therefore, I feel that 'b' was slightly better than 'a', but the difference is really small. --Dansc



[Diagram]
Wrong (iii)

Also wrong is Black 1 here. White 2 and 4 leave a and b as miai for the kill.



[Diagram]
Variation

Making the eye as large as possible, with Black 1 here, seems to be correct as well, but it is not the solution from the book. After White 2, Black 3 follows, and Black lives as shown. White 3 is followed by Black 2, White a, Black 7. White 7 is answered by Black 3. White 4, Black 7. White 5, Black 4.


[Diagram]
Variation (2 at 1-2 point)

If Black 1 is a mistake, then it must be because White can next play at 2. If Black now plays 3, White 4 kills the entire black group. But ...


[Diagram]
First try

... when Black throws in at 3, White fails.



The authors of the variations shown here, have not yet found the reason why 1 in the main line is preferred to 1 here.

--DieterVerhofstadt

[Diagram]
Suggestion

I received the following suggestion. White 2 is sente against Black 1. If Black doesn't answer ...


[Diagram]
Main line

4 at 1. The result is ko.


Bill: Maybe this is the main line.

[Diagram]
Variation 1

W5 takes ko.

Black lives with B4 and B6, sacrificing a few stones.


[Diagram]
Variation 2

B4 fills ko.

To avoid that, maybe White should start with W1. Now B4 fills and W5 is sente. This is better for White than the next diagram.


[Diagram]
Variation 3




[Diagram]
No sente

White's descent here is not sente.



Back to Kanazawa Tesuji Series
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This is a copy of the living page "Kanazawa Solution Three" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.