Henry Seishiro Okazaki, was born in the town of Kakeda, Fukushima Prefecture, Japan, on January 28, 1890. He migrated to Hawaii in 1906 and settled in Hilo, Hawaii. At the age of 19 he was diagnosed as having a lung disease thought to be tuberculosis. As a desperate measure to combat depression, he began his study of Judo under the tutelage of Master Yoshimatsu (Kichimatsu) Tanaka at the Shinyu Kai Dojo in Hilo. The arts fascinated him and eliminated his frustration over his illness. He practiced with all his strength and being. Strangely, his devotion led to a complete recovery from his illness.
Professor Okazaki studied various martial arts, including the Hawaiian fighting art of lua, from a Hawaiian man in Puna, Hawaiʻi.
Professor Okazaki eventually formed an eclectic system which he called "Kodenkan". This system included Judo, Jujitsu, Hawaiian Lua, Okinawan Karate, Chinese Kung Fu, and American Wrestling. Breaking with tradition, Prof. Okazaki taught not only the Japanese, but any and all races.
He gave the name "Danzan Ryu" to his school of Jujitsu, in which Okazaki also incorporated a number of lua strikes he had mastered from a Lua man in Puna, Hawaii. These ʻai or lua strikes were passed down to Professor Libert O ʻ Sullivan.