Submission Wrestling

Submission wrestling (also known as submission fighting, submission grappling, sport grappling, or simply as No-Gi) or Combat wrestling (in Japan), is a formula of competition and a general term describing the aspect of martial arts and combat sports that focus on clinch and ground fighting with the aim of obtaining a submission using submission holds. The term "submission wrestling" usually refers only to the form of competition and training that does not use a "jacket", "gi," or "combat kimono," often worn with belts that establish rank by color.

Read more on Wikipedia.