No ko variations . Black will avoid losing a point at if he wins the ko.
stretching is approximately as good, but everything depends on the possibility for Black to escape --Dieter
tderz:  not descending to , assuming that the overal result will be unwished for white, even if black were not ko-ing with
Ba-Wb (Bm ...-Wn in case of more white ko threats), but simply taking Bc-Wb.
The simple =b is territorily good too but gote.
What will happen after Black stretches to ?