The site “Seosomun 5 District Urban Environment Improvement” characteristically faced Seosomun-ro connecting Sejong-daero and Seosomun History Park, while it overlooked the beautiful view of Deoksugung Palace to the north. Located along the important route in central Seoul, the site embraces the symbolic meaning of a gate into the capital and the urban context connecting the site with the city’s past. Haeahn Architecture divided the square mass diagonally to complete the concept of “Landmark Gate” connecting corners and the roof. By connecting the front and back of the site, formerly cut off, into an open area in the style of the Ssamzie building in Insa-dong and the sunken area and by planning a small three-dimensional park, we were able to naturally overcome the difference in the ground level which was as large as 3 meters. The masterplan aimed to restore the memories of the street once active during the Joseon dynasty and the urban flow starting from Deoksugung Palace to Sejong-daero by way of Seosomun Presbyterian Church.