Sueojangdae Post (Defense Commander's Post) is a two-story military facility used as a lookout post as well as for directing battles. This structure was built on the western side of Namhansanseong Fortress as one of the four command posts. During the Manchu Invasion of 1636, King Injo personally commanded and encouraged the troops from here. They held out for 45 days against a Qing force of 120,000, before finally being forced to surrender and accept vassal status to the Manchu Empire.