[2] On July 14, 2004, Tahara took part in the 4th East Japan Amateur Shooto Tournament, competing in the flyweight (114 lbs) division.
[5] His third place allowed him to compete in the 12th iteration of the All Japan Amateur Shooto Championship, where he finished as the third best, same as the previous year, losing to Shinya Murofushi in the semi-finals.
[8] Tahara was scheduled to face Kenichi Sawada, in his second professional appearance, at Shooto: 11/30 in Kitazawa Town Hall on November 30, 2006.
Tahara was scheduled to face Hiroyuki Abe in the opening round of the tournament at Shooto 2007: 6/30 in Kitazawa Town Hall on June 30, 2007.
Tahara was scheduled to face Takehiro Ishii at Shooto: Shooting Disco 4: Born in the Fighting on February 23, 2008.
[11] Tahara was scheduled to face Atsushi Takeuchi at Shooto: Shooting Disco 5: Earth, Wind and Fighter on June 21, 2008.
[14] Tahara was scheduled to face Shinya Murofushi at Shooto: Shooting Disco 9: Superman on June 6, 2009.
[15] Tahara was scheduled to face Jesse Taitano in the main event of Shooto: Gig Saitama 1 on August 9, 2009, in a 119 lbs catchweight bout.
[17] Tahara rebounded from this loss with a second-round technical knockout of Junji Ikoma at Shooto: Border: Season 2: Vibration on March 28, 2010.
[18] Tahara was scheduled to fight Mitsuhisa Sunabe in a light flyweight title eliminator match at Pancrase: Passion Tour 8 on September 5, 2010.
[20] Tahara was scheduled to face Akinobu Watanabe at Shooto - Gig Tokyo 11 on August 25, 2012, and won the fight by majority decision.