The art was adapted from Daitō-ryū Aiki-jūjutsu as it was taught by Choi Yong-sool (최용술) when he returned to Korea after World War II after having lived in Japan for 30 years.

Currently, though, the second character is preferably written in Japanese using shinjitai, which replaces the original 氣 with the modern, simplified 気, thus reducing the number of strokes by four.

The interview also asserts that he travelled with him as a teaching assistant, that he was employed to catch war deserters and that he was the only student to have a complete understanding of the system taught by Takeda.

Kondo Katsuyuki (current head of the mainline Daito Ryu) has however released a page from Takeda Sokaku's eimeiroku that contains Choi Yong-sul's name.

[9] Choi Yong-sool's first student, and the man whom some claim helped him develop the art of hapkido was Seo Bok-seob, a Korean judo black belt when they met.

Some of Choi's other respected senior students are: Chinil Chang, Lim Hyun-soo, Ji Han-Jae, Chung Kee-tae, Kim Moo-hong, and arguably Suh In-hyuk (Korean: 서인혁) and Lee Joo-bang (Korean: 이주방) who went on to form the arts of Kuk Sool Won and modern Hwa Rang Do respectively (though some argue that their training stems from time spent training under Kim Moo-hong).

A few of the notable students were: His son Sam Choi, Daniel Ray Walker, and Roman Nikolaus Urban who founded the Chun Ki Do Association in Africa and Europe, Jaeshin Cho his Nephew and Gregory Jump His first Top-student.

He details that prior to opening his martial art school in Seoul, the Sung Moo Kwan (성무관), he also supposedly studied from a man known as 'Taoist Lee' and an old woman he knew as 'Grandma'.

To this end and with the support of the Head of the Security Forces, Park Jong-kyu, Ji founded the very successful Korea Hapkido Association (대한 합기도 협회) in 1965.

Three of Ji Han-jae's notable students in Korea were Kwon Tae-man (권태만), Myung Jae-nam (명재남) and Chang Young-shil (장영실) who is the current president of the International Hapkido Federation.

[15] Chang's intimate video interview(one of several over decades) with his teacher Doju Choi during his visit to New York City has been abused through numerous interpretations and translations.

[22][23][24] Black Belt Magazine, respecting Chin-il Chang as the second lineage successor, asked him to write a brief obituary on Choi that appeared in the April 1987 issue.

Upon returning to Korea in 1970, Kim looked to Ji Han-Jae's move to set up his own organization and with the encouragement of his students followed suit and founded the Korean Hapkido Association in 1971.

His early years were difficult and he worked in a factory during the day while he taught at a struggling hapkido school in the evening located in an economically depressed area.

He was not a direct high level student of Grandmaster Yong-sul Choi but created and crafted his own limited version from various other teachers that he expanded and taught throughout the world.

Kim Jung-soo (김정수) was born and raised in the Taegu area, Korea, and started training Hapkido directly under Choi Yong-sool (최용술) in 1957.

Later, his students began opening branch schools throughout the greater Taegu aerea, under various names, but still considered to be part of the Yun Bee Kwan (윤비관) family.

These schools are known to hold tightly to the original teachings of Choi, Yong-sool (김정수), while also including most of the refinements done by Kim Moo-hong (김무홍) in terms of kicking methods.

[28] In 1972, Myung Jae-nam (명재남) was one of the original members of the Korea Hapkido Association (대한 합기도 협회), which was formed in 1965 at the request of the South Korean President Park Jeong-hee.

Lee served as an Instructor with the 1st Special Forces Group in the Korean Army, and has taught martial arts to the Police Departments in Seoul as well as Plainfield, New Jersey.

[30] Kim is the founder of the Bum Moo Kwan style, in which the practitioner is instructed to finish the encounter quickly, using any available material as weapon or any part of his body, aiming the opponent's pressure or vital points.

Residing, teaching and training in Brazil since 1977, Kim was the master of several Hapkido World Champions, such as Norberto Serrano Jr., Rafael Tercarolli and Leandro Heck Gemeo.

Through the courtesy of his teacher at that time Grand Master Lim, Hyun-soo, president of the Jung Ki-kwan, he obtained a 4th dan certificate signed by Founder Choi Yong-sul.

(Although, these tactics generally tend to be focused upon escaping and regaining footing or controlling, striking, and finishing a downed opponent, rather than lengthy wrestling or submission grappling engagements.)

As terminology varies between schools, some refer to defensive maneuvers as soolgi (술기; loosely translated as "technique-ing"), while hoshinsool (Korean: 호신술; Hanja: 護身術; RR: hosinsul; meaning "self-defense") is preferred by others.

They combined these forms together with the yu sool concepts for striking taught to them by Choi and during a period of 8 months training together in 1961 finalized the kicking curriculum which would be used by the Korea Hapkido Association for many years to come.

Han Bong-soo studied under Gwonbeop (Korean: 권법; Hanja: 拳法) and Shūdōkan karate from Yoon Byung-in (윤병인), whose students were influential in the later forming of Kong Soo Do and Taekwondo styles, specifically the Chang Moo Kwan and Jidokwan.

Hapkido typically introduces this technique off a wrist-grabbing attack where the defender makes a circular movement with his hands to free himself from the opponent's grasp and applies a pronating wristlock while cutting down upon the elbow joint with their forearm, taking their opponent down to the ground, where an elbow lock is applied with one's hand or knee to immobilize the attacker in a pin.

Many hapkido organisations may also include other weapons training such as a sword (gum; 검), long staff (Korean: 장봉; Hanja: 長棒; RR: jangbong), middle length staff, nunchaku (Korean: 쌍절곤; Hanja: 雙節棍; RR: ssangjeolgon), war-fan or other types of bladed weapons such as twin short swords.

While training methods vary, a typical training session will contain technique practice (striking techniques as well as defensive throws and grappling), break falling (Korean: 낙법; Hanja: 落法; RR: nakbeop), sparring, meditation and exercises to develop internal energy (ki, Korean: 기; Hanja: 氣; RR: gi).