Tangchundaeseong Fortress was built along the steep mountain ridge connecting Inwangsan to Bibong Peak of Bukhansan, serving as a 'connective fortress' that unified Hanyang City Wall and Bukhansan Fortress into one system and protecting the western outer areas of the capital. The fortress walls were constructed by stacking stones only on the outer side according to the topography, which well demonstrates the fortress construction techniques of the late Joseon period in preparation for large scale cannon warfare. Tangchundaeseong Fortress is evaluated as a unique and rare heritage in Korean fortress history as a connective fortress linking the capital fortress and the inner fortress. In particular, King Yeongjo completed a large-scale capital fortress system connecting the capital— connecting fortress shelter fortress, and promulgated the Royal Edict on Defense (Suseongyuneeum) to the people, pledging to defend the capital together with military and civilian forces. The Capital Fortifications of Hanyan emonstrates the creative development of the Joseon Dynasty's capital defense system.