After World War II, members of the United States military learned karate in Okinawa or Japan and then opened schools in the US. In 1945 Robert Trias opened the first dojo in the United States in Phoenix, Arizona, a Shuri-ryū karate dojo. In the 1950s, William J. Dometrich, Ed Parker, Cecil T. Patterson, Gordon Doversola, Donald Hugh Nagle, George Mattson and Peter Urban all began instructing in the US.
Tsutomu Ohshima began studying karate under Shotokan's founder, Gichin Funakoshi, while a student at Waseda University, beginning in 1948. In 1957 Ohshima received his godan (fifth degree black belt), the highest rank awarded by Funakoshi. He founded the first university karate club in the United States at California Institute of Technology in 1957. In 1959 he founded the Southern California Karate Association (SCKA) which was renamed Shotokan Karate of America (SKA) in 1969.
In the 1960s, Anthony Mirakian, Richard Kim, Teruyuki Okazaki, John Pachivas, Allen Steen, Gosei Yamaguchi (son of Gōgen Yamaguchi), Michael G. Foster and Pat Burleson began teaching martial arts around the country.
In 1961 Hidetaka Nishiyama, a co-founder of the Japan Karate Association (JKA) and student of Gichin Funakoshi, began teaching in the United States. He founded the International Traditional Karate Federation (ITKF). Takayuki Mikami was sent to New Orleans by the JKA in 1963.
In 1964, Takayuki Kubota relocated the International Karate Association from Tokyo to California.