SnotNose: Alive. needed to avoid a ko. If
at
, Black can squeeze for life.
Why not at
? If the shape is alive even with fewer outside liberties, shouldn't the potential of B playing at
be kept for later (ie making
gote)?
unkx80: Suppose the White wall is changed as shown. Playing at a gives 5 points, while playing at b gives 4 points. Maybe that's the intention of the problem author?