gasana:
With the extra stone at m18, caranthir sequence can not threathen a ko anymore i think

posetcay:
White can hane at F1 in sente to make a ko anytime, so I feel like there should be a stone at around H2 for this problem.

caranthir:
I disallowed one way of killing - it was not a clean kill but dependent on the outside. Problematic sequences below for reference.

caranthir:
SGF