sentences:  As a youth, he trained in martial arts, basketball, boxing, gymnastics, and weights.Later, he was an instructor in the Korean Marines for three years, teaching unarmed combat to the Marine Commandoes, Marine Brigade Headquarters, and the Marine 2nd Infantry Division.Under the direction of the KTA, Rhee helped introduce the art of taekwondo to Southeast Asia—most notably in Malaysia and Singapore, but also in Hong Kong, Indonesia, and Brunei.