What does OSS mean in BJJ?

The exact origin of OSS is debated, with theories tracing it to the Japanese phrase Onegaishimasu meaning please, or to Oshi Shinobu meaning to push through. In BJJ, it has become a catch-all expression of acknowledgment and respect. Some gyms use it constantly while others rarely use it at all. It is generally safe to use when greeting your instructor, acknowledging a technique demonstration, or showing respect to a training partner. However, be aware that some BJJ practitioners find its overuse to be performative or unnecessary. When in doubt, observe how your gym uses it and follow suit. At competition events, you might hear it used liberally among competitors and coaches.