When did they use Tae Kwon Do for self defense?

Answer 1

This is a rather vague question since you would have to specify who "they" are. However, Taekwondo has been used for self defense from the time it was first established as the national Martial Art of Korea, until today. Even before the name Taekwondo was officially used to describe the Korean Martial Art, the curriculum of striking with punches and kicks, throwing and grappling was taught in Korea for centuries, and used both in the military, and among villagers to defend themselves.

Our modern culmination of Taekwondo was used in post WWII Korea from 1945 until 1950 in combating the street gangs and criminals that were wreaking havoc on the newly liberated society at the end of the Japanese occupation. From 1950 to 1953, Korea was engaged in a civil war between the communist north, and the Republic of Korea in the south. Soldiers of the South Korean ROK Army were trained in special hand-to-hand combat tactics that were proven very effective.

Following the Korean War, the surviving Kwans (Martial Art schools) and their leaders organized to form a unified system which was officially called Taekwondo on April 11, 1955, but underwent some name changes until 1965 when the name was finally agreed upon. The Korea Taekwondo Association (KTA) was formed in 1959, and officially registered with the Korean government in 1961. Many of the high ranking Masters were dispatched abroad to give demonstrations, and teach Taekwondo to foreign military personnel. During the Vietnam War (1955 - 1975), Korean soldiers trained in Taekwondo formed an elite group of special forces that were feared among the North Vietnamese and Vietcong, and the communist soldiers were reportedly advised to avoid encounters with the ROK Tiger division at all cost.

From the 1960's on, Taekwondo has been spreading to many countries on all inhabited continents, and has been used for self defense by many practitioners in both the military, and civilian population. Even as Taekwondo tournaments grow in popularity in the sport arena, Taekwondo remains one of the most deadly and effective forms of self defense in the world. Some schools are dedicated specifically to sports, while others remain focused on self defense, and many maintain a balance of both.