Hamaguchi debuted in 1969 with
International Wrestling Enterprise. He was a regular midcarder although his teams with Sueo Inoue and
Rusher Kimura were main event. He also made forays into North American wrestling in the late 1970s, winning titles in
Puerto Rico's
World Wrestling Council and
Canada's
Stampede Wrestling. In 1981, when IWE collapsed, Hamaguchi teamed with Kimura and Isamu Teranishi in an "invasion" angle in
New Japan Pro-Wrestling. When the angle was dropped, Hamaguchi joined
Riki Choshu in forming the original Ishin Gundan rebel stable. In 1984 Ishin Gundan left NJPW and formed
Japan Promotion, which eventually became a mere stable of
All Japan Pro Wrestling. AJPW promoter
Giant Baba ordered Choshu to replace Hamaguchi, who was rather small-sized, with rookie
Yoshiaki Yatsu in order to feud with
Jumbo Tsuruta and
Genichiro Tenryu in the upper card. Hamaguchi thus reformed his team with Inoue in the lower card. After Japan Pro Wrestling broke up and Choshu and others went back to NJPW in 1987, Hamaguchi chose to retire. In 1990 he returned as
Big Van Vader's partner against
Antonio Inoki and
Tiger Jeet Singh in Inoki's 30th anniversary match. Hamaguchi competed sporadically until settling in Tenryu's
WAR in 1993. In his last earnest comeback he teamed with Tenryu and
Koki Kitahara to win his last title, the
WAR 6-Man Tag Team Championship. ==Retirement==