Located 25km southeast of downtown Seoul, Namhansanseong was originally built as a defense structure. During the Joseon Period (1392-1910), diverse facilities were built here and the walls were expanded to transform it into a temporary capital for use in the event of an emergency. The structure incorporated all the concepts of military defense engineering available at that time, including the castle systems of China and Japan, as the techniques for building castles and fortresses were changing with the adoption of firearms from the West. Since then it has served as a defense facility for the areas close to Seoul, and people have continued to live within the area. Traces of former military, civilian, and religious facilities can still be seen there.
Criterion (ⅱ): The design and construction of Namhansanseong incorporated all the military defense engineering concepts available in Southeast Asia in the seventeenth century. The fortress was built in consideration of the new threat posed by the adoption of firearms from western countries, based on a review of the castle systems of Korea and China. The construction of the fortress was an important turning point in fortress design in Korea.
Criterion (ⅳ): Namhansanseong is a good example of a fortified city. The installation of facilities to enable the fortress to be used as a temporary capital in the event of an emergency was carried out by Buddhist monks in the seventeenth century. The defense of the fortress was also assumed by them.