From The Martial Arts Encyclopedia
Hapkido (also spelled hap ki do or hapki-do) is a dynamic and somewhat eclectic Korean martial art. In the Korean language, hap means "harmony", "coordinated", or "joining"; ki describes internal energy, spirit, strength, or power; and do means "way" or "art". It is usually translated as "the way of coordinating energy" or "the way of coordinated power." .
Hapkido contains both long range fighting and infighting techniques but the goal of most scripted training situations is to get near for a close strike lock , or throw Hapkido emphasizes circular motion, fluid movements , and control over ones opponent . It's practitioners usually seek to gain advantage through footwork and body positioning to employ leverage , avoiding the use of strength and opting for technique.
Hapkido's method of kicking leans toward commitment to the strikes and less concern for quick retraction of the kicking leg . As in other arts, such as Muay Thai, hapkido's emphasis is about power and commitment rather than speed . It is usually all about the hips . Traditionally, Choi Yong Sul's Yu Kwon Sul kicking techniques were only to the lower body, but most flavors of Hapkido include some high kicks and flashy jumping , turning kicks .
Most Hapkido uses a variety of strikes with the hand . Ranging from boxing to “energy strikes” to eye gouges and fish hooking and strikes that claim to penetrate deeply to damage internal organs .
Joint manipulation techniques
Much of hapkido's joint control techniques are said to be derived largely from aikijujutsu. They are taught similarly to aikido techniques,
Hapkido's joint manipulation techniques attack the large joints ( elbow, shoulder, neck, back, knee , etc) and small joints (wrists, fingers, ankles, toes, etc. ).
These techniques are used to cause pain and force a submission or to gain control of an opponent for a 'come along' techniques (as is often employed in law enforcement), and sometimes ever to assist in a throw or to cause the dislocation or breaking of the joint if they resist the throw .
Hapkido has kept a great many techniques which are applied against the joint that were said by some “to be inconsistent with aikido's more pacifistic philosophy”.
Hapkido is well known for its use of a wide variety of wristlocks. These techniques are believed to have been derived from Daito-ryu aikijujutsu although their application is not always identical not the results .
Many of early practitioners of hapkido had very strong judo influences , including Choi Yong Sul's first student Suh Bup Sok. ,who obtained his black belt very early in life . It is believed that these techniques were absorbed into the hapkido curriculum from judo as there were a great many judo practitioners in Korea at that time and its tactics were commonly employed in the street and sport fighting of the period.
A small portion of the Hapkido curriculum which consists of techniques specifically designed to thwart judo .
The judo/yudo techniques were however adopted with adjustments made to make them blend more completely with the self defense orientation which most hapkido stresses. For example many of the judo style throwing techniques employed in hapkido do not rely on the gi . Instead in many cases they rely upon gripping the limbs, head or neck in order to be successful like wrestling or “no gi”.
As the hapkido students advance , they learn how to employ and defend against common weapons. The first weapons one encounters in most dojangs is the knife (kal, 칼). Then , basic techniques and defenses with the short stick (dan bong ), walking cane (jipangee,), and the rope . Some styles also incorporate the long staff (jang bong), middle long staff (jung bong), nunchaku , and the sword (Gum) .
Hapkido employs "soft" techniques similar to aikido and "hard" techniques reminiscent of taekwondo and kick boxing. The "hard" techniques emphasize circular rather than linear movements for the most part . Hapkido is an extremely eclectic martial art, and different hapkido schools emphasize different techniques and training methods . However, some core techniques are found in each school , and all techniques should follow the three principles of hapkido :
("Hwa") Non-resistance is remaining relaxed and not directly opposing an opponent's strength.
("Won") Circular Principle can basically simplify into " torque for power generation ".
The Water Principle
("Yu") (lesser used "Ryu") Water Principle can be explained as strength and speed through fluid movements , while constantly filling your opponents space , or with tons of Bruce Lee quotes .
There is a historical link to Daito-ryu aikijujutsu which is generally acknowledged ... ... generally .
The rest of it's history is fairly complete and well documented starting at around the 1950's .