Your legs vs his head: One of the basic features of Jiu jitsu is the notion of controlling greater strength and aggression with lesser strength and aggression via mechanical and tactical advantage. One of the surest ways to do this is to use the strongest parts of the human body (legs and hips) against the weaker parts (head and shoulders for example). Two excellent examples of this would be the triangle and juji gatame arm bar – both of which directly match your legs against an opponents head and arm. Whenever possible look for this kind of match up in your favor. IF YOU ARE TO DEFEAT BIGGER AND STRONGER OPPONENTS THEN YOU MUST SEEK TO FIGHT YOUR OPPONENTS UPPER BODY WITH YOUR LOWER BODY AS MUCH AS POSSIBLE. If you make it a battle of your upper body against a similarly skilled and bigger opponents upper body it is unlikely you will win. MAKE IT A FIGHT BETWEEN YOUR LOWER BODY AND HIS UPPER BODY AND VICTORY WILL FIND A PATH TO YOUR DOOR OFTEN.