井上亘
With a sports background in boxing and jujutsu, Yamamoto passed an audition held by New Japan Pro-Wrestling (NJPW) in September 2001 and began training professional wrestling at the promotion's dojo the following March. During his training, Yamamoto also travelled to Los Angeles to train at the local NJPW dojo. Yamamoto made his in-ring debut on October 12, 2002, facing Wataru Inoue in Korakuen Hall.