About TKD and HKD
TAE KWON DO
Tae Kwon Do, the Korean national sport, is one of the world's most commonly practiced sports. In Korean, Tae means "to kick or destroy with the foot"; Kwon means "to punch with the fist"; and Do means "way" or "art". Hence, Tae Kwon Do is loosely translated as "the art of kicking and punching" or "the way of the foot and the fist." As with many other martial arts, Tae Kwon Do is a combination of combat technique, sport, exercise, entertainment, and philosophy.
Physically, Tae Kwon Do develops strength, speed, balance, flexibility, and stamina. The five tenets of Tae Kwon Do (courtesy, integrity, perseverance, self control, indomitable spirit) reflect that Tae Kwon Do is a mental discipline as well as a physical one. Tae Kwon Do helps students develop improved awareness, confidence, focus, discipline, memory, and respect.
HAP KI DO
In the Korean language, Hap means "together", "coordinated", or "joining"; Ki describes internal energy, spirit, strength, or power; and Do means "way" or "art". Thus, Hap Ki Do translates literally as "joining-energy-way", but it is most often rendered as "the way of coordinating energy" or "the art of coordinated power." Hap Ki Do employs joint manipulations, locks, pressure points, throws, kicks, and strikes primarily for self-defense.
Hap Ki Do practitioners learn to use and control their own "Ki" and that of the attacker. This is because Hap Ki Do emphasizes circular motion, non-resistive movements, and control of the opponent. Although Hap Ki Do contains both outfighting and infighting techniques, the end of most situations is to get near for a close strike, lock, or throw. Hap Ki Do practicioners seek to gain advantage through techniques, avoiding the use of strength against strength.
(From Wikipedia: Tae Kwon Do and Hap Ki Do)