(No. 108: May 18, 1998)
Elementary level: Answer
Black 1 is the vital point to kill White.
Elementary level: Wrong Answer
Black 1 allows White to get a Ko with 2.
Intermediate level: Answer
Black 1 is the vital point. White
cannot help but create a Ko with 2.
Intermediate level: Reference Diagram
If White takes at 2, Black 3 hits the vital point.
After Black 9, White cannot do anything because it is
short of liberties. Note that the exchange of
the moves Black 1 and White 2 makes White short of liberties.
(This becomes the same shape as the problem No.108.)
Intermediate level: Wrong Answer
Black 1 and 3 cannot succeed.
White is alive with the moves to 8.
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