[1] Koichi gained recognition fighting in organizations like RISE and MARS, then went on to win the M-1 Heavyweight Muaythai title in 2009 and the WPMF Japan Heavyweight Muaythai title in 2010.

Having spent most of his career at heavyweight, Koichi dropped to light-heavyweight following back-to-back losses to Jerome Le Banner in GLORY events.

He retired from active competition in November 2017 to become a trainer.

He collided with a car while driving a scooter in Tokyo.

He was declared dead shortly upon arrival at the hospital.