(No. 352: Jan. 20, 2003)
Black 1 and 3 are crucial.
If White 4, Black wins the capturing race with 5 and 7.
Elementary level: Answer (Variation)
White can create a Ko with 4 and 6,
but this Ko is very serious for White.
Black 1 is the vital point.
White has to create a Ko with the moves 2 to 8.
Intermediate level: Wrong Answer
Black 1 allows White the vital point 2 and loses the capturing race.
(The same shape as the preceding problem)