Hapkido owes its vast range of techniques to influences from many different styles, most notably, the Japanese Daito Ryu Aikijujutsu and the Korean Tae Gyun. Other aspects were added from the differing martial arts styles of native Korea, including aspects from Taoist monks. By having such a rich heritage, Hapkido has benefited by having aspects that cover all ranges of techniques found in most martial arts.

Grandmaster Ji Han Jae (Hapkido Do Ju Nim - Founder) Grandmaster Ji Han Jae was born in Andong in Korea in 1936. He initially began his training under Choi, Yong Sul learning Japanese Yawara (Yu Kwon Sul), he is considered to be one of Choi's top students.

Grandmaster Ji began his mental training under a man known as Taoist Lee, from Lee he learnt the use of the Bo, the short stick, Korean Tae Gyun kicking methods and meditation. A lady monk known only to Grandmaster Ji as "Grandma" taught him spiritual power. From these skills, Grandmaster Ji created "Hapkido". Grandmaster Ji is also a healer proficient in acupressure & chiropractic medicines, as well as being a spiritual teacher adept at various forms of meditation.

Grandmaster Ji was the chief bodyguard to Korean President Park, Chung Hee, during this time he was the chief martial arts trainer for the 300 Korean secret service bodyguards, the Korean police ad the Korean Special Forces. He was an instructor to President Richard Nixon's Secret service bodyguards, as well as instructing the FBI & OSI. Receiving awards from Korean President Park and American President Nixon for his outstanding excellence in training specialist personnel.

Grandmaster Ji was the instuctor to most of the top Hapkido masters of the world today, such as, Kwang Sik Mayung, Tae Man Kwon, Bong Soo Han (Billy Jack movies), He Young Kim, Myung Jae Nam, Oh Se Lim, and Jin Pal Kim (Jackie Chan's Instructor).

Grandmaster Ji has also been involved in the movie industry with appearances like the Game of Death (with Bruce Lee). During this time in Hong Kong Grandmaster Ji was a trainer and choreographer and personally instructed many martial arts stars. Amongst these were Bruce Lee, Samo Hung (Jackie Chan's partner), Angela Mao & Carter Wong (Big Trouble in Little China).

In 1984 Grandmaster Ji moved to the United States, at that time he added more mental and philosophical aspects to the technical aspects of Hapkido, with that he added the words Sin Moo to Hapkido. "Sin" meaning the higher mind and "Moo" meaning the fighting or martial art. Therefore Sin Moo Hapkido means the "Harmony & Coordination between Mind, Body & Spirit.