Seoammun (Western Secret Gate) is an ammum which is an inconspicuous and hidden out of sight from the enemy. It was used by people to bring weapons, ammunition, and even animals into the fortress.
This hidden gate is located just south of Seojangdae (Western Command Post).
There are in total five secret gates located inconspicuously at Hwaseong Fortress.
Construction on Seoammun (Western Secret Gate) was completed on June 18, 1796.