Answers

(No. 154: Apr. 5, 1999)

Elementary level: Answer

Black 1 is crucial to kill White unconditionally.
After White 2, Black kills White with 3 and 5.
If White 2 at 3, Black 2 kills White.

Elementary level: Wrong Answer

Black 1 lets White get a Ko with 2.

Intermediate level: Answer

Black 1 is the vital point of this shape.
After White 2, Black gets a Ko with the moves 3 to 7.

Intermediate level: Wrong Answer 1

Black 1 allows White to play at the vital point 2
and to live with the moves to 8.

Intermediate level: Wrong Answer 2

Black 1 is wrong, too. White lives with 2 to 6.