115NN Notcher

115NN  

Unsettled: There are several moves that live for Black (e.g. see 115NS Notcher), but if White starts, it's ko.

White makes ko  

This sequence assumes that neither threatens to escape nor to build an eye, and, of course, the ability of to start the ko depends on the existence of .

usually no internal threat  

Also note that even though it might look like White could use , as a local threat, that would instead let Black use as a threat to save most of Black's stones.