Black to make ko  

LukeNine45: Perhaps this?

xela: No, W6 at 'a' and there is no ko. Unfortunately though I don't know what the correct answer is! I want to play B1 at W2, but I can't see a followup that works.

LukeNine45: Duh. Good point. I wanted to start that way too, but also didn't see a continuation! hmmm, how about this:

W8 at W4  

xela: I don't think this works either: W4 at W6?

LukeNine45: You mean this? Still ko, no?


xela: Yes, ko.

This way of avoiding it doesn't work.  
white is trapped  

xela: white can try to break out this way, but I don't think it works.

Another idea  

xela: I think this does the job, but there are quite a few variations...

variation 1: ko  

Maybe W2 is wrong: can white live if B3 is at 'a'?

variation 2: another ko  

This way is not so good for white, as black gets to take the ko first.

variation 3: white dies  

If W4 at B5, the result is similar to variation 4 below.

variation 4: complicated!  

This is the part that I (xela) find difficult. B1 can't escape, but white has a dead shape. (If W4 at 'a' instead, then B5 at W4.) I'm sure there are a few more variations, so I may have made a mistake.

LukeNine45: W4 at b? hmmm, no then B5 at W4...

Variation 5  

LukeNine45: I think white lives this way?

xela: If black plays B3 at 'a', then the eye at 'b' can be squeezed shut, same as in variation 4 above?

Variation 5.1  
Variation 5.2  
Variation 5.3  

LukeNine45: hmmm this looks both bad and unavoidable...

xela: ... so now we seem to have two solutions!

modified; 10 at 4, advantage white!

This seems to be forced all the way  

GokyoShumyoSection3Problem40/Attempts last edited by on January 11, 2013 - 18:40
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