This one shows you to push the knife held arm froward then grab the bad guy's knife arm away and go under him then subdue him and attack him in self defense especially during a wartime situation but if it is just a street criminal attack then you will have to stop once the danger passes and just knock him out cold then get police & ambulance help but if it is in a wartime situation then you will have to kill him on the spot because the enemy soldier will not hesitate to kill you if he gets up again.
http://www.kobukaijujitsu.com/knifesmall.mpg