[3] Yamamoto's three fight winning streak was snapped at AJKF LEGEND-VIII on September 13, 2000, as he fought to a unanimous decision draw with Naoki Ishikawa.
[6] This two-fight winning streak earned Yamamoto the fight Naoki Ishikawa in a trilogy match at AJKF KNOCK DOWN on September 27, 2003, in an AJFK super featherweight title eliminator.
He won the fight by a second-round technical knockout, after knocking Ishikawa down three times by the 2:12 minute mark of the second round.
[11] After making his first successful title defense, Yamamoto was booked to face Jonathan Muyal in a non-title bout at AJKF RUSH!
[14] Yamamoto was then booked to face Kompayak Fairtex at AJKF SWORD FIGHT Japan vs Thailand on October 16, 2005.
[17] Yamamoto rebounded from his title loss with a first-round knockout of Kanongsuk Fairtex at AJKF SWORD FIGHT 2006 on March 19, 2006.
[22] Yamamoto was booked to fight a quadrilogy bout with Naoki Ishikawa at AJKF Spring Storm on April 24, 2008.
He lost the fight by a third-round technical knockout, as the ringside physician stopped the bout due to a cut on Yamamoto's forehead.
[23] Yamamoto was scheduled to rematch Wanlop Weerasakreck at M-1 FAIRTEX Muay Thai Challenge Legend of Elbows 2008 〜YOD MUAY〜 on August 10, 2008.
[26] Yamamoto extended his winning streak to three straight fights at AJKF Norainu Dengekisakusen 2009 on June 21, 2009, with a unanimous decision victory against Jaumeaw Phumpanmuang.
Yamamoto took part in the inaugural Krush lightweight tournament, and faced Keiji Ozaki in the opening round which took place on August 14, 2009.
He first lost to Rashata by technical knockout at NJKF on May 9, 2010, which was followed by a unanimous decision loss to Kanongsuk Weerasakreck at Sengoku Soul of Fight on December 30, 2010.
[29] Yamamoto suffered his fourth straight professional loss to Kan Itabashi at REBELS.8 & IT’S SHOWTIME JAPAN countdown-1 on July 18, 2011, who beat him by an extra round unanimous decision.