125WNNotcher

Black playing first  

Black lives after playing at one of a to h.

White playing first  

White can force ko: After White can be thought of having already played at a, too. The only exception (apart from filling the notch and dying with 6) would be Black playing at b, but this would leave one eye on the right and no eye on the left. So Black is forced to play at c sometime in the sequence. White at d then kills the notch-eye and opens the ko for life (with White playing first).