In junior high school, he also studied judo and kendo.
He began the study of Shito-ryu karate at the age of 10. After beginning training in Kobudo Bujutsu or staff, Iwata was advised by Mabuni to study Jojutsu, or short staff, under Seiko Fujita. In 1943, Iwata received a Jojutsu Shihan diploma from Fujita.
After graduating from Toyo University in 1944, Iwata also received a Shihan diploma from Mabuni.
After the death of Fujita in 1966, Iwata became heir to many of his styles, but not of Kōga-ryū Wada Ha Ninjutsu. Later years
In 1960, Iwata established the Nihon Karate-Do Kai Eastern Japan and became its first president
In 1964, he became vice-president of the All Japan Karate-Do Federation Shito-Kai. In 1969, he became the Saitama Prefecture Karate-Do Federation vice-president
In 1972, he became an All Japan Karate-do Federation first grade referee.
He died of heart failure in 1993.