(No. 241: Dec. 4, 2000)
Elementary level: Answer
Black 1 is the vital point to capture
the three White stones and live.
Elementary level: Answer (Variation)
If White 2, Black 3 to 5 captures the White stones to live.
Elementary level: Wrong Answer
Black 1 allows White the vital point 2.
Black has nothing further to do.
Intermediate level: Answer
Black 1 is crucial to get a Ko.
Intermediate level: Reference Diagram
If White 2, Black connects at 3.
After Black 7, White cannot help creating a Ko with 8.
Intermediate level: Wrong Answer
Black 1 fails. After White 2 to 4,
there is no way that Black can live.