UFC Japan: Ultimate Japan (aka UFC 15.5) was a mixed martial arts event held by the Ultimate Fighting Championship on December 21, 1997, in Yokohama, Japan. The event was seen on pay per view in the United States, on cable TV in Japan, and was later released on home video. It featured a four-man heavyweight tournament, the first ever UFC Middleweight Championship bout, a Heavyweight Championship bout, a Superfight and was the first UFC appearance of MMA legends Kazushi Sakuraba and Frank Shamrock. It was the first event to be located in a country other than the United States or its territories.