The Hidari Gonon-the traditional symbol of Okinawa with special significance especially those practicing the ancient art of Okinawan Karate. The Koyasan Shingon sect of Buddhism which came from China to Japan uses the Hidari Gomon as a visual representation of the cycle of life. Also Shinto related because in Shinto mythology the symbol is often used to signify the structure taking place between three worlds. Such worlds include heaven, Earth, and the Underworld.
Mitsu-domoe (三つ巴), Japanese mon (紋) emblem
Okinawan Kobudo: The History, Tools, and Techniques of the Ancient Martial Art by Andrea Guarelli http://www.amazon.com/dp/1634504844/ref=cm_sw_r_pi_dp_eL2Mwb136ZES5