Concentration of force: Among the most foundational axioms of all forms of combat is that of concentration of force. The idea is to take a large percentage of our strength and apply it against a low percentage of an adversary's strength at a vulnerable and important point where, if the attack is successful, the opponent will not be able to continue the fight. Jiu Jitsu, like all intelligently crafted approaches to combat, is based around this principle, most obviously through the use of submission holds, which are a very clear example of concentration of force in practical application. One of our favorite examples will always be the triangle (sankaku) which pits the strength of both our legs and hips against an opponent's single arm and neck. It works not just one vulnerable point, but two (strangles and locks to the entire arm). Within the triangle family one of our big favorites is the rear triangle (ushiro sankaku) which creates an especially impressive demonstration of concentration of force as you can see in this picture of outstanding junior squad member Nick Ronan. Note the total isolation of head and arm and the power restraining forces of the legs and hips that immediately create both a strangle threat and arm lock threat. This is the ideal of Jiu Jitsu. Make the study of concentration of force your life's work in Jiu Jitsu
