victories against Koichiro Kimura and Nobuhiro Tsurumaki, and a decision win against Nobuaki Kakuda. In 1994, Nagai looked to ascend the scale by taking part on the Mega Battle Tournament 1994, eliminating Ameran Bitsadze on the first round, but then losing to Chris Dolman in the second. By 1995, RINGS was transitioning into a mixed martial arts promotion, and he faced Dick Vrij in a shoot rematch held in RINGS Holland on February 19, 1995, but he fell knocked by a knee strike while Vrij was illegally holding the ropes in the corner, an action which went unnoticed or the referee, and the decision was not overturned. However, Mitsuya would get booked for a trend of victories back in Japan, beating the likes of Andrei Kopylov, Yoshihisa Yamamoto and Carl Greco. He finally would get his retribution over Vrij submitting him via heel hook in an MMA fight on August 24, 1996. Nagai then fought Tsuyoshi Kohsaka, overwhelming the judoka with kicks, palm strikes, body punches and knees while Kohsaka fended off the strikes with takedowns and submission attempts. However, when the fight was brought back to standing Nagai beat him with knees, earning a TKO victory and one of the biggest wins of his RINGS career. He then got another MMA victory against Willie Peeters, winning via heel hook, but his momentum got cut short by a submission loss to Kiyoshi Tamura at the Mega Battle Tournament 1996. In 1997, Nagai competed in several MMA fights, losing his first three, with two of those losses coming via mismatched contests against heavyweight fighter Joop Kasteel. He then got notable wins against Valentijn Overeem, Andre Mannaart and Chris Haseman, all by heel hook. In 1997, Nagai got a license by the All Japan Kickboxing Federation and competed at the Kick Over IX event as a RINGS representative. It would be his last year in the promotion, as he left RINGS after a match with Akira Maeda in which Maeda shot on him after the bell, although it is possible it could have been a worked shoot. Kickboxing and later MMA career (1997-2013) After leaving RINGS Nagai briefly pursued a career in kickboxing, and fought in K-1 between 1997 and 1999. His kickboxing career was unsuccessful, and he retired with a record of 6 losses and 1 draw in August 1999. On March 2013, Nagai returned to MMA after 15 years away