矢野通
Initially Yamamoto worked low card matches for NJPW, normally on the losing side to gain ring experience. On December 27, 2003, Yamamoto lost to Ryusuke Taguchi in a chance at a match on NJPW's most prestigious show, the January 4 Dome Show "Wrestling World". Yamamoto participated in the 2004 Young Lion Cup where he defeated Hirooki Goto, Akiya Anzawa, and Hiroshi Nagao to earn a total of six points, not enough to qualify for the finals. Yamamoto also participated in the 2005 Young Lion Cup where he only won one match, defeating Yujiro. In 2006, Yamamoto participated in his first G1 Climax tournament, losing all four matches. Yamamoto teamed up with Manabu Nakanishi to compete in the 2006 G1 Tag League, defeating Giant Bernard and Travis Tomko to earn their sole victory in the tournament. On January 8, 2006, Yamamoto and Osamu Nishimura defeated Toru Yano and a returning Togi Makabe. Over the summer of 2007 Yamamoto began teaming regularly with Hiroshi Tanahashi forming a team called "New Japan Dragons", earning a match for the IWGP Tag Team Championship against the then champions, Bernard and Tomko, albeit in a losing effort. For the 2007 G1 Tag League Yamamoto teamed up with Takashi Ilzuka, while they defeated three teams (Hirooki Goto and Milano Collection A.T., Togi Makabe and Toru Yano, and Giant Bernard and Travis Tomko); the team ended up in last place. On November 2, 2007 Yamamoto wrestled his last match for NJPW, teaming with his mentor Yuji Nagata in a losing effort against Tomohiro Ishii and Toru Yano.