Reuven: W anwser is marked, B can't kill like this
Tapir: Looks very killable, I try again later :) I like these problems very much. So small but not easy at all.
MrTenuki: Is this what you're thinking about? Reuven: yes but it does look too good for B, I guess 2 should've been either at 4 or 3 in this diagram, afterall...