Cage Force(former name Demolition Octagon Gear (D.O.G.)) is a defunct Japanese Mixed Martial Arts (MMA) organization operated by Greatest Common Multiple (GCM) Communication. It was the first Japanese MMA organization to feature an octagon cage instead of a ring. Yushin Okami, Eiji Mitsuoka, Kuniyoshi Hironaka and Keita Nakamura experienced a cage match in D.O.G before contract with UFC.