Sensei Iwata started his Karate training in 1986 in his hometown of Kyoto, Japan. When he moved to New York a few years later, Sensei Iwata joined the U.S. Oyama Karate Organization (or, as it was later named, the World Oyama Karate Organization) and started training under Soshu Shigeru Oyama, founder of World Oyama Karate, or "Full Contact" Karate at his dojo. Soon after, he became Soshu's Uchideshi, or private pupil. After successfully achieving his first black belt, Sensei Iwata became an assistant instructor under Soshu Oyama to further his training. During this time, Sensei Iwata participated in several Ultimate Challenges, Full Contact Knock Down Tournaments, and Semi-Knock Down Tournaments. He retired from tournament fighting in 1992, but continued his Karate training at Soshu's Dojo for several years thereafter.
In 2004, Sensei Iwata achieved an Instructor’s certificate from World Oyama Karate Organization and began teaching his own Karate course, "Karate for Adults" at the YWCA of Manhattan. Finally, at the beginning of 2005, Sensei Iwata moved to a rental dance studio and started the World Oyama Karate Iwata Dojo.
On January 15th 2008, after a 20 year association, Sensei Iwata left the World Oyama Karate Organization and simply named his Dojo, Karate-do Iwata Dojo and using his family crest as Iwata Dojo’s crest.