(No. 392: October 27, 2003)
Black 1 is the vital point.
If White 2, Black wins with the moves 3 to 7.
This is quite an easy problem,
but I once saw an amateur strong player miss this in a game.
Black 1 and 3 are crucial to create a Ko.
After White 4, Black plays 5. If White 6, Black takes Ko at 7.
|:||takes Ko at|
Intermediate level: Answer (Variation)
If White 4, Black plays 5.
White cannot help creating a Ko with 6.
Intermediate level: Wrong Answer 1
Black 1 allows White to live with the moves 2 to 8(Seki).
Intermediate level: Wrong Answer 2
Black 3 allows White to live with the moves 4 to 10.