Eli Knight, Royce Gracie Black Belt:

An actually practical defense against a knife attacker that leads to a realistic disarm. Knife disarms are a very tricky topic and there is a TON of misinformation floating around about this subject. 

* This is a very dangerous technique and should only be practiced in a controlled, safe environment under supervision of a qualified instructor. You should NEVER attempt to engage an opponent with a weapon, or otherwise, if there is any possible way to avoid doing so.