Just as sonbaes in Koguryo competed in Subak games at the time of their national festivals, Hwarangs in Silla also played Subak games, such as "dokkyoni" and "taekkoni," at such festivals as "palkwanhoe" and "hankawi." During the dan-o festivals (on the 5th of May of the lunar calendar), Subak competitions were held along with games of Korean wrestling, tug-of-war, and hopping contests. In July and August, an annual national festival was held for the Hwarang to demonstrate their martial art skills. Another game of amusement was "doo-ho" (a game of pitching arrows into a pot).
The Hwarang were warriors who were disciplined at an early age to endure all types of weather and hardships. As fighters, they were legendary. They further developed Subak, which until then was primarily practiced as an art form, by adding hand techniques, kicks, mental discipline, and principles to transform it into a useful combat skill. Their extensive mountain running endurance training gave them strong legs, and as their leg muscles developed, they began to incorporate formalized kicking techniques into Subak. They developed a martial art system of foot fighting named, "Subak-gi," which is believed to be the initial source of the extensive number of kicking techniques used in Korean martial art styles.
The famous Korean historian, Dr. Danjee Shin Chae Ho, in his writings of ancient Korea, describes Subak-gi contests of skill and courage under grueling conditions where certain events were held on the frozen river to test a contestant's courage and perseverance. The winner of a contest was given the title of son-bi was held in esteem by all. Dr. Danjee states that the art of Subak-gi was eventually introduced to China as "kwon-bup."