Brazilian Jiu-Jitsu (BJJ) is a martial art and combat sport that focuses on grappling and especially ground fighting. It is a derivative of early 20th century Kodokan Judo, which was itself then a recently-developed system (founded in 1882), based on multiple schools (or Ryu) of Japanese Jujutsu.

It 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 chokeholds 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.