tasuki: After E17C18B18, black should play B19. I think it's alive, but at the very least it's a stronger answer. After A18B17, either B16C19E19F19 wins the semeai, or E18A17 there are a couple variations but it seems the hero lives in all of them?
posetcay: I agree that S1 is the proper resistance, revamped the solution.
After E17 C18 B18, black should play B19. I think it's alive, but at the very least it's a stronger answer. After A18 B17, either B16 C19 E19 F19 wins the semeai, or E18 A17 there are a couple variations but it seems the hero lives in all of them?