hoshi911:
North-West Problem. Black to kill Having tried so many sequences, I felt a bit lost, when the problem was solved after only 3 moves: bS18, wS17, bP19. At first glance, it was no so clear to me, why the problem stops here. I suggest to add at least one forcing sequence, how to continue, e.g. wR19, bQ18, wR18, bT18, wT17, bT15.

babao:
This problem seems a bit empty? Maybe some more wrong sequences would help.