Sueojangdae (守禦將臺 Defense Commander's Post) is a two-story military facility used for observation as well as for directing battle. This structure was built in 1624 as one of five (two in the east and one each in the other directions) command posts inside Namhan Mountain Fortress. Today, Sueojangdae is the only one that remains. It sits atop 482m Cheongryang-san (Mountain) and offers a panoramic view of the fortress interior as well as the cities of Yangju, Yangpyeong, Yong-in, Goyang, Seoul and even Incheon. Originally the lookout was built as a one-story structure called the West Command Post (西將臺).
The Namhan Mountain Fortress Defense Command (守禦廳 Sueocheong) was organized into five divisions (Front, Left, Right, Center, and Rear), and this post was for the Commander of the Right. During the Manchu Invasion of 1636 King Injo himself helped to direct and encourage the troops from here. They held out for 47 days against a Qing force of 130,000. In 1751, Special Mayor Yi Gi-jin, on orders from King Yeongjo, had a second story built on the West Command Post.
The tablet on the outside reads Sueojangdae (Defense Commander's Post), but inside another tablet is inscribed with the words "2-story Tower of No Forgetting" (無忘樓). It serves as a constant reminder to succeeding generations of the hardship suffered by King Injo when he surrendered to the Qing as well as by the Crown Prince. King Injo's son was held hostage for 8 years in Shenyang (China), and after he became King Hyojong he plotted a retaliatory expedition against the Qing, but it never came to pass. King Hyojong was buried in a royal tomb at Yeoju, and his descendents, Kings Yeongjo and Jeongjo, would periodically visit the tomb to perform ancestral memorial services. On the way, the Joseon monarchs would stop by this command post and reflect on the humiliation that it represented for all in the kingdom.