King Jeongjo was of the opinion that it would be wiser to withstand an attack than flee to the mountains. Consequently, in the Hwaseong Fortress design process he eschewed mountain fortress experience in favor of a new design. To this extent he chose prominent Silhak (practical science) scholars. His request was for them to research well-built fortress and figure out a way to build a solid fortress. One such scholar, Jeong Yakyong (so called "Dasan"), researched many books from China that dealt with design and construction of high walls, watchtowers and double hung gates.
Another important feature was the use of bricks. The Silhak scholars of the day insisted on using bricks to build houses instead of the traditional lumber. The reason for this was that over-logging in the 18th century created lumber supply shortages. King Jeongjo did not wish his project to add to the shortage of material for home building. However brick making not only requires soil and clay but kilns as well. The Silhak scholars reasoned that even though several kilns would be needed for the construction of Hwaseong Fortress, they would eventually be used to supply bricks to the general population.
As a project, Hwaseong Fortress was designed and constructed more for political and economical purposes than for military purposes. It was part of a larger planned city consisting of modern urban infrastructure. In addition to the common facilities such as bridges and streets, the new city was to have public facilities such as water reservoirs and farms run by troops stationed nearby (so called "Doonjeon"). Unlike other fortresses in China and Japan in the 18th century, Hwaseong is a unique "Pogoksik" (valley-enveloping) mountain fortress built on a level site with nearby mountainous land. Hwaseong was designed to function as a military, political, and commercial entity.
Figure 5: Facility guide map of Hwaseong Fortress
Since Hwaseong Fortress was designed to serve a military purpose, there were 5.7 km of high walls surrounding 48 main facilities serving the military purposes. The design included many unique features that would strengthen the weak points of other fortresses of the day. These include four main gates, two water gates, five secret gates, two command posts at the top of the Paldalsan mountain, twelve sentry posts, two big watch towers, two crossbow towers, five artillery posts, and a beacon deck with five towers.
There are 48 main structures in Hwaseong some of which are described in the following sections.