Rebels was established by the former two-weight Martial Arts Japan kickboxing champion Genki Yamaguchi on December 1, 2009, with the aim of popularizing the sport of
muay thai in
Japan. The inaugural event was held jointly by M-1 Challenge and Cross-Point on January 29, 2010, and was headline by a lightweight bout between
Arashi Fujihara and TOMONORI. Starting with the third event, Rebels-EX, Cross Point broke their partnership with M-1 and remained as the sole promoter and organizer of the events. On June 11, 2011, Rebels announced a partnership with the Dutch-based
It's Showtime, which allowed cross-promotion and mutual exchange of fighters under contract. The first joint event was held on July 18, 2011, under the name “Stand up JAPAN!” REBELS × IT'S SHOWTIME 〜 REBELS.8 〜 and was headlined by a -61 kg title eliminator between Rebels contracted
Kan Itabashi and
Genki Yamamoto. On October 28, 2012, Rebels announced events from that point forward would be held under two rulesets: Rebels rules, which was similar to
K-1 and Rebels Muay Thai rules, which allowed for elbows, sweeps and five-round bouts. Rebels entered into a partnership with
Knock Out on May 20, 2019, which likewise held events under kickboxing and muay thai rules. On June 15, 2020, Bushido Road sold Knock Out ownership rights to Def Fellow, the operating company of Rebels. The final Rebels event, "REBELS~The FINAL~", was held on February 28, 2021. A month later, the brand was merged with Knock Out. ==Rules==