Danzan-Ryu (檀山流, "Sandalwood Mountain System" from a Chinese name for Hawaii) is a Ryu of jujutsu founded by Henry Seishiro Okazaki (1890–1951) in Hawaii.
Danzan Ryu is ubiquitous in the United States, particularly on the west coast.
For a Danzan Ryu syllabus, see Danzan Ryu Lists.
Seishiro Okazaki was born in Fukushima Prefecture, Japan in 1890. In 1906, he immigrated to the island of Hawaii. Soon after, he was afflicted with a pulmonary condition which may have
been tuberculosis. It was during this time, however, that young Okazaki began studying under Yoshin-ryu jujutsu sensei by the name of Yoshimatsu Tanaka in Hilo, Hawaii.
Okazaki intensely pursued his studies under Tanaka and he found after sometime that his respiratory condition had gone into remission. Okazaki felt that the study of martial arts had
played a large role in his physical recovery and as a result he decided to dedicate his life to the study and teaching of jujitsu and related disciplines. Later in his life he would adopt
the western name, Henry.
In 1924, Okazaki returned to Japan and underwent a study of the various schools, or ryu-ha, of the then most popular Jujutsu styles of Yoshin-ryu, Namba-Shoshin Ryu, Iwaga Ryu, Kosogabe
Ryu, Kodokan Judo, and several others. Later that year when he returned to the Hawaiian Islands, he continued the study of jujutsu under the various masters who had emigrated from Japan
to Hawaii. Incorporating not only traditional jujutsu, but also Hawaiian Lua, Okinawan Karate, Eskrima, Kung Fu, and wrestling, he began to synthesize the most effective aspects of these
various styles into an eclectic system which he called 'Danzan Ryu'. Okazaki used this name to honor his Chinese martial arts teacher, Wo Chong.