Sacrifice five to kill
Difficulty: Beginner Keywords: Life & Death
This is the technique in its abstract form. It involves a capturing race in which the attacker willingly sacrifices 5 stones ...
... to next kill with a throw in and a play at the vital point. Incidentally, the throw-in is better style than playing immediately, for reasons of ko threats and ko value.
The crux is to create potential for throw-in, and not, as here, allow White to capture four stones solidly, after which she is alive.
Reference
This technique is mentioned in the hard section of gogameguru's problem set week 14: http://gogameguru.com/weekly-go-problems-week-14/.