Sacrifice a single stone on the second line 3
This is game 3 of the 1997 French? Championship.
Considering that was a deep invasion, the timing of is good. It can be considered as a probe. Later in the game White's response might be different.
The way White then played was questionable: bad shape.
White would have done better with here. is effectively forced.
The point about shape here is that the cutting point at a is not a serious defect.
Comment by Seong-june Kim 6d, from the unpublished book 'Fighting Fit'.