Brazilian Jiu-Jitsu (BJJ) is a martial art and combat sport that focuses on ground fighting and submission holds. It was developed and popularized in Brazil in the 20th century, and has since become one of the most widely practiced martial arts in the world.

BJJ is known for its effectiveness in self-defense and its emphasis on technique and strategy over size and strength. It teaches practitioners how to control an opponent using leverage and proper body positioning, and allows smaller, weaker people to defend themselves against larger, stronger attackers.