The belt system in BJJ is generally more fluid. There’s no universal way for an individual to achieve the next rank. Most of the schools out there don’t have traditional gradings, where a student performs in order to move up a belt. Instead, most of the time, this is a decision that is left up to the professor. The decision to promote someone will more than likely depend on how they're doing in class in both live rolling and understanding the techniques they've been taught. Sometimes, a school may have a grading class when a professor judges which students are ready to move up. After an excellent performance in competition, it's common for a student to receive a belt promotion. In fact, the competitor may even get their next belt right after the end of the match or on the podium when they're getting their medal.