Shinichi Kojima: MMA Career and Key Results

Shinichi “BJ” Kojima is a Japanese flyweight who spent much of his career in Shooto. A southpaw wrestler, he held the Shooto world bantamweight title from 2006 until 2010 and became known for a long-running rivalry with Mamoru Yamaguchi.

Shooto champion and Yamaguchi rivalry

Kojima and Yamaguchi first fought to a draw in 2006. They met again later that year for the Shooto bantamweight championship, and Kojima won by rear-naked choke. Their rivalry continued through further title bouts, including a 2008 defense in which Kojima submitted Yamaguchi with a guillotine choke. Kojima remained champion until a right-knee ACL injury prevented him from defending the title within Shooto’s required period, and he vacated the belt in 2010.

ONE Championship and later fights

Kojima later competed in ONE Championship. He defeated Rey Docyogen at ONE: Return of Warriors in February 2013, then faced Andrew Leone in a non-title bout at ONE: War of Nations in March 2014. Leone won by unanimous decision. Kojima continued competing in Japan, with Sherdog listing a July 2022 RIZIN bout against Yutaro Muramoto as his most recent professional fight.

Kojima’s technical wrestling and repeated title fights made him a central figure in Shooto’s lower-weight divisions. Related: MMA and Japanese fighters.

Career Milestones

Kojima’s Shooto championship belonged to the promotion’s historical bantamweight class, a lighter category than the 135-pound bantamweight division familiar to many modern MMA viewers. His later ONE appearances were at flyweight. Keeping those promotional weight-class names in their historical context helps explain a career that crossed organizations without necessarily involving the same limits attached to each label. His repeated meetings with Yamaguchi also distinguish a sustained championship rivalry from a single title challenge. Their sequence included both a draw and submission finishes, rather than a run of identical results.

Kojima was born in Yokohama on February 6, 1979. His nickname “BJ” identifies the same Shooto veteran across later promotional records.

Sources

Sherdog: fight history; Sherdog: Shooto title defense announcement; Pancrase official event date; Biographical source.

Article Tags

Shinichi Kojima, Mixed Martial Arts, Sports History