Military personalities were among the well-known prominent national leaders during the Three Kingdoms Era. This military orientation led to the development of warrior groups, such as Koguryo’s "chouisonin,” individual members were called “sonbae,” and the sixth century Silla warrior nobility group known as "hwarang-do" (individual members were called hwarang). Both groups adopted subak training as one of their important learning subjects and both used the same organizational and hierarchical structure.
During Koguryo's initial stage of national foundation, the kingdom organized the Sonbae in its attempt to concentrate its power. According to historians, the word sonbae means "a man of virtue who never recoils from a fight."
Sonbae warrior cadets were chosen at festivals called "sin-su-do," held during March and October. Events used to select sonbae cadets included archery, sword dancing, and subak. The subak competitions sometimes involved fighting in pits with wild animals. After sonbaes were selected, they lived together in a group. The Chronicle of Old Joseon describes how sonbaes immersed themselves in learning Subak, fencing, archery, riding, military tactics, and sometimes enjoying various games including Korean wrestling (ssirum). The book also describes how that, during peacetime, sonbaes wore the finest silk and devotedly guarded the kingdom, constructed roads and fortresses, and acted as teachers, all for the benefit of society. In wartime, they would organize and defend the kingdom with their strong willed bravery, always ready to sacrifice their lives for the nation. The sonbae became legendary for their feats of bravery. The Koguryo government operated on a merit system where the best warriors were appointed to the highest positions.
As discussed above, of the three ancient Korean kingdoms, Silla was the first formed, but it remained the smallest and least civilized. The two larger kingdoms, along with Japan, constantly attacked Silla, which was weak and disorganized. Since Silla’s coastline was constantly under attack by Japanese pirates, Silla appealed to King Gwanggaeto, the 19th in the line of Koguryo monarchs, for help against the continual attacks. Gwanggaeto sent a force of 50,000 soldiers into neighboring Silla to help the smaller kingdom drive out the pirates. During this time, the "hwarang" youth military group developed.
Subak was popularized in Koguryo by the sonbae and handed down to the hwarang warrior group in Silla, as evidenced by the following:
- "Hwarang" in Silla had the same meaning with the word "sonbae" in Koguryo.
- Both hwarang and sonbae had the same organizational and hierarchical structure.
- Both the sonbaes and hwarangs played subak games at festivals
Subak was further popularized by the Hwarang who added more foot techniques to the art and spread its influence throughout the Korean peninsula.