Choi Yong Sul (Hangul: 최용술) is often seen as the source of Korean hapkido. After Choi returned to Korea in 1946 he started teaching a martial art he had learned in Japan, Daito Ryu Aikijujitsu. His initial students and their students, etc., adapted these techniques to their own needs and added techniques from other Korean and non-Korean styles, forming Hapkido, Kuksool Won, Hwarangdo, Tukgongmoosul, Hanmudo, Hanpul, etc.,.
Kim Yun Sang aka Kim Yoon-Sang (김윤상) began using the term "Hapkiyusul" in 1987, a year after Choi Yong Sul died, in order to differentiate what he had learned from Choi Yong-Sul and was teaching from mainstream Hapkido. Kim was authorized by Choi Yong Sul to use Choi's own name ("Yong Sul") as the name of his kwan (Yong Sul Kwan (Hangul: 용술관)). Hapkiyusul members practice the original techniques and learning/teaching process as taught to Kim Yun Sang by Choi. Choi's students were told that all of these techniques (including the kicks and hand strikes taught by Choi) were Daito Ryu Aikijujitsu. The use of hapki (better known as aiki in Japanese traditions) is greatly emphasized.
Outside of Korea there are a few dedicated people who actively train in Hapkiyusul. At the moment there at least 30 non-Koreans who hold a black belt in Hapkiyusul. Schools or practice groups exist in the US (Texas), Australia, Brazil, England, Germany, Italy and the Netherlands.
Kim Yun Sang holds seminars in Australia at least every other year and visited several European countries in February 2008, teaching seminars in Germany, England and Italy.
^Kim, He-Young. History of Korea and Hapkido. Andrew Jackson Press, Baton Rouge, Louisiana 2008
^Restall, Barrie, "Yong Sul Kwan: History of the Korean Hapkido Hapkiyusul Headquarters", Taekwondo Times, November 2006; Lawrence, Jason, "What's Your Flavour?", Australasian Taekwondo, Vol.15 No.2; and Kim, He-Young. History of Korea and Hapkido. Andrew Jackson Press, Baton Rouge, Louisiana 2008
^Kim, He-Young. History of Korea and Hapkido. Andrew Jackson Press, Baton Rouge, Louisiana 2008 and also see Restall, Barrie, "Yong Sul Kwan: History of the Korean Hapkido Hapkiyusul Headquarters", Taekwondo Times, November 2006