The Suwon Hwaseong Fortress is a flat and mountainous fortress, which cannot be found in other neighboring countries like China and Japan. It was constructed for dual functions ― military defense and commercial functions. With its scientific, rational, and practical structures, it can be called the finest among the fortresses in Asia. The walls were piled up applying the method of ‘owechuknetak’ in which while outer walls were piled up, the inner sides were made by raising the grounds using the natural topographical features. Influenced by the silhak which literally meant practical studies, and was the scholastic and social movement in those days to try to find practical challenges in real life of people avoiding unrealistic philosophical controversies in neo-Confucianism, various kinds of advanced technology ― mixed use of bricks and stones; device of hyeonan, or flutes on the wall to pour hot water to enemy soldiers climbing the wall, and nujo, or gutter on the wall; creation of geojunggi, or crane; and wall-piling up with wood and bricks ― were actively applied in constructing the fortress. It can be regarded as a rare superb example of fortress construction technology of Asian fortresses. <Source from Suwon Cultural Foundation>