Hrewsahgs:
Okay, let's try one more time. Instead of playing H2 here, black can play E3 to force a ko instead of a clean kill for white...unless I'm missing something.

Hrewsahgs:
Whenever I try to link the position I'm trying to point out, it keeps showing other variations instead, for some reason. Anyway, it's partially fixed already, just missing the strongest refutation that can make a ko in one of the green solution trees. Thanks!

Hrewsahgs:
In the alternative variation (B D18 instead of B F17), couldn't black resist by playing E17 instead of H18 to make a ko? In light of that, shouldn't white play H18 instead of F17? Seems like the shape is too cramped for black to live after that.