玄菟郡
Micheon continuously developed the Goguryeo army into a very powerful force. During the disintegration of China's Jin Dynasty, he expanded Goguryeo's borders into the Liaodong Peninsula and the other Chinese commanderies. Since the commanderies were nuisances to be eliminated for Goguryeo’s stability, the first military campaign in 302 headed against the Xuantu Commandery, with conquering Daedong River basins of current Pyeongyang. Consolidating cut-off between commanderies and Chinese mainland, Goguryeo also annexed the Lelang commandery in 313 and Daifang commandery in 314 after attacked Seoanpyeong (西安平; near modern Dandong) in Liaodong. The series of subjugation around northern Korean peninsular and Manchuria held its significance given that 400-year presence of Chinese forces was completely cleared out of Korean peninsular.