It promotes the principle that a smaller, weaker person can successfully defend himself against a bigger, stronger assailant.
By using leverage and proper technique—most notably by applying joint-locks and chokeholds to defeat the other person.
Brazilian Jiu Jitsu can be trained for sport grappling tournaments (gi and no-gi) and mixed martial arts (MMA) competition or self-defense. Sparring (commonly referred to as 'rolling') and live drilling play a major role in training, and a premium is placed on performance, especially in competition.