In 1098, Yun went to an ambassador of Northern Song dynasty, and told the court information about Sukjong's coronation.

Goryeo, however, did not have a powerful army at that time, due in part to a century of peaceful existence.

After experiencing the invasion by the Jurchen, Yun Kwan realized that Goryeo lacked efficient cavalry units, and requested permission from King Sukjong to train and reorganize the current Goryeo military into a professional army that would contain well-trained cavalry units.

Finally, in 1107, General Yun led the newly formed Goryeo army, a force of approximately 170 thousand men called Byeolmuban, and attacked the Jurchen tribes.

To mark the victory, General Yun built nine fortresses to the northeast of the Goryeo-Jurchen borders (동북 9성; 東北 九城).

With the rise of the Jin, Goryeo was no longer able to trade with the Song dynasty or any of the other neighboring nations, and became isolated, which contributed to the weakening of the kingdom.