Brazilian jiu jitsu ( BJJ ) is a martial art and combat sport that focuses on grappling and especially ground fighting with the goal of gaining a dominant position from which to force an attacker to submit.

Bjj system developed from a modified version of pre-World War II Judo including some techniques from Japanese Jujutsu and with a focus on ne-waza (ground technique). It promotes the principle that a smaller, weaker person using leverage and proper technique can successfully defend themselves against a bigger, stronger assailant.

BJJ can be trained for self defense, sport grappling tournaments (gi and no-gi) and mixed martial arts (MMA) competition. Sparring and live drilling play a major role in training, and a premium is placed on performance, especially in competition.

Brazilian jiu jitsu began with Mitsuyo Maeda (later known as Count Koma), a Japanese expert judoka and member of the Kodokan. Jigoro Kano sent Maeda overseas to spread his Judo to the world. Eventually, Maeda emmigrated to Brazil in the 1910s where an influential businessman named Gasto Gracie helped him get established. In return for his aid, Maeda taught the fighting art to Gasto's son Carlos Gracie, who then taught the art to his brothers, including Hélio Gracie.

When Maeda taught the art to the Gracies he called it Jujitsu instead of Judo. It is not known why he chose the name Jujitsu because Maeda had only trained in Jujitsu for a very brief time as a child. There is much speculation and debate over this. One theory is that because Maeda was fighting in no hold barred type matches that Kano felt was against the principles of Judo, Maeda changed the name because of a falling out with Kano.

Another theory is that Maeda included many dirty techniques in his teaching that had originated from classical jujitsu. At the time it was simply known as Jiu-Jitsu - not Gracie Jiu-Jitsu or ;Brazilian Jiu-Jitsu ( bjj ). These latter terms came to be when the Gracies came to the United States to spread their art. Jiu-Jitsu was also the original spelling of the art in the West and that is why this style retains the original (although technically incorrect) spelling of the art. Other common spellings are Jujitsu, Jujutsu, Ju jitsu and Ju-Jitsu.

The Gracie brothers trained many of their sons, who carried on the family tradition. Through constant technical refinement in training and real fighting, emphasizing ground-work, Brazilian Jiu-Jitsu as it is known today was created. The Gracie family continued to develop bjj system throughout the 20th century, often fighting vale tudo matches (precursors to modern MMA), during which it gained its focus on ground fighting and refined its techniques.