Originally, Korea was divided into three kingdoms: Silla in the southeastern part of the country, Goguryeo (Koguryo) in the northern part, and Baekje located west of Silla. The Subak style was created in the Korean kingdom of Goguryeo.
It was a style that utilizes hand strikes, kicks, jointlocks, and throws. The mountainous terrain of Goguryeo may have made its people have legs relatively stronger than their arms.
The word Sonbae is translated to mean "a man of virtue who never retreats from a fight", and is a member of the warrior corps. Those who were members of the Sonbae lived in groups and learned archery, Kakju (ancestor of ssireum) and Subak (ancestor of taekkyon), history, literature, and other liberal arts. Although they were constantly training in combat, during peace time they helped construct roads and fortresses, assisted after natural disasters and so on.
In the year 400, in an attempt to dominate the entire southern portion of the country, Baekje invaded Silla. King Gwanggaeto the Great of Goguryeo is said by some accounts to have sent 50,000 Sonbae troops to Silla's aid. Later he would attempt to dictate Silla's internal affairs because of this assistance.
Split
Subak took a heavy blow during the Joseon period, which was founded on the ideology of Confucianism, stressing literary art instead of martial art. Subak was only allowed to be practiced in competitions called subakhui. After three subakhui bouts, the winner could become employed as a soldier.
It was also during the beginning of the Joseon dynasty that Subak became increasingly divided into two separate styles, Taekgyeon and Yusul (which is another term for subak). Where Taekgyeon techniques consisted mainly of kicks and strikes, Yusul techniques were of the locking and grappling kind.
But just as often this divide is already made between subak and galjeok in earlier times by scholars.