(No. 195: Jan. 17, 2000)
Elementary level: Answer
Black 1 is crucial. White 2 is also crucial,
and it results in a Ko.
Elementary level: Wrong Answer 1
Black 1 is wrong. White 2 creates
a five-point Nakate, and Black dies.
Elementary level: Wrong Answer 2
Black 1 is also wrong. White cuts at 2, and
Black cannot do anything more,
because it is short of liberties. Black dies.
Intermediate level: Answer
Black 1 is the vital point. If White 2,
Black plays 3 to 7 and gets a Ko.
Intermediate level: Wrong Answer
Black 1 lets White play on the vital point 2.
Black loses the capturing race.