(No. 399: December 15, 2003)
Black 1 is crucial.
If White 2, Black kills White with 3 and 5.
Black 1 is the vital point.
If White 2, Black gets a Ko with 3.
Intermediate level: Answer (Variation)
If White 2, Black gets a Ko with 3 and 5.
Intermediate level: Reference Diagram
Black 1 also gets a Ko with the moves to 7,
but it is a two-stage Ko, less advantageous to Black.
|:||takes Ko at|