By 1965 he was a 7th Dan in Judo. In 1969, Tamura was awarded the Black Belt Magazine Hall of Fame for Judo Instructor. In 1972 he operated a dojo in California.
Tamura originally trained in Seattle Dojo.
Mas Tamura was promoted to 3rd degree black belt by Jigaro Kano. Tamura was instrumental in developing the hand to hand techniques used by the United States Armed Forces.
This was after defeating an opponent over 50lbs more than himself. Tamura is a former President of the United States Judo Federation.