The 14th century saw the expansion of the Chinese Ming and the contraction of the Mongol Empire. Kublai Khan's forces were weakened by repeated attacks on Japan and by warfare with the Chinese under the Ming Dynasty, so the Koreans, under the leadership of General Yi Song Gye were able to defeat the Mongols in 1364. After years of internal guerrilla warfare, the Koryo Dynasty was over thrown in 1392 AD and the Yi Dynasty, who swore allegiance to the Ming Dynasty of China, came to power.
The Yi Dynasty rejected Buddhism and embraced Confucianism as the national religion. A well functioning Confucian bureaucracy came into existence, which brought about an orderly social structure and rapid educational development.
Subak in Koryo Dynasty
Subak played an important role as a popular sport activity of the people in the dynasty. During the early days of the dynasty, Subak proficiency was the only required qualification to join the military. Historical records indicate that people from both Chungchong and Cholla provinces once gathered at the village of Chakji, located along the provincial boundaries, to compete in Subak. Subak became an important national sport, practiced in contests called "Subakhui." Historical records indicate that the format and judgment of such contests became fairly standardized with elements of sparring (kyorugi) and breaking (kyokpa) competition. Subak attracted much attention from both the royal court and the public but, since the early Koryo Dynasty was a time of peace, Subak was of little use to the common man.