RTG Problem 89 / Solution
The key move is this
. It is wrong for
to throw-in at a.
The three Black stones cannot connect.
Again, Black cannot connect after
. Due to the presence of the
stone, Black will be captured in a ladder if Black insists on connecting.
The huge Black group is captured.
Throwing in first actually allows the Black group to go home, due to the existence of the
stone.