[2] Gichin Funakoshi played a major role in introducing karate from Okinawa to Japan, adjusted to reduce injury and merged with approaches for athletic training.

[3][4] General uneasiness on how karate was taught by the JKA instructors and disagreements on Funakoshi's funeral arrangements in 1957 motivated some of the senior karateka connected with Funakoshi, but not associated with the JKA, such as Shigeru Egami, Genshin Hironishi, and Tsutomu Ohshima, to form their own organizations, such as Shotokai and Shotokan Karate of America).

[5] They claimed to practice a version of Shotokan karate closer to what Funakoshi taught, as compared to the JKA style.

[3][6][7] Under Nakayama's leadership, a generation of respected instructors spread karate worldwide, guided from the JKA headquarters in Tokyo.

Clive Nicol, in his classic book Moving Zen, describes the karate practice at the JKA's honbu dojo (headquarters training hall) in Tokyo during the early 1960s, from his unique perspective as a western karate student going from white to black belt in a few years.

Karateka such as Dave Hazard (UK),[17] Ennio Vezzuli (Brazil), Nigel Jackson (South Africa), Peté Pacheco (Portugal), Malcolm Fisher (Canada), Leon Montoya (Colombia), Richard Amos (UK, US), Pascal Lesage (France) and others, are mentioned in karate forums as having completed the JKA instructors' course (or having had substantial participation in it) but do not appear on the list of graduates as published in 2008 on the JKA's website.