Brazilian Jiu-Jitsu (BJJ) is a martial art and combat sport

that focuses on grappling and ground fighting.

BJJ promotes the principle that a smaller, weaker person using leverage and proper technique can successfully defend against a bigger, stronger assailant using joint-locks and choke holds to defeat an opponent. BJJ can be trained for self defense, sport grappling tournaments (gi and no-gi) and mixed martial arts (MMA) competition. 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.

For more information check out:

1.   http://en.wikipedia.org/wiki/Brazilian_Jiu-Jitsu
   

1.   http://www.ibjjf.org/jjh.htm