It promotes the principle that a smaller, weaker person can successfully defend themselves against a bigger, stronger assailant using leverage and proper technique; most notably, by applying joint-locks and chokeholds to defeat them. Brazilian Jiu-Jitsu is a martial art and combat sport that focuses on grappling but especially ground fighting. It was derived from the Japanese martial art of Kodokan Judo in the early 20th century, which was itself then a recently-developed system (founded in 1882), based on multiple schools (or Ryu) of Japanese jujutsu. 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.