Seojangdae (Western Command Post), known as a jangdae, was defended by troops who observed the nearby area for any signs of enemies.
Construction on the structure began on August 11, 1794 and was completed in just over a month on September 29, 1794. King Jeongjo personally wrote the sign that hangs above.
In honor of his father, Jeongjo commanded troops from this location on February 12, 1795.
Seojangdae (Western Command Post) has twice been destroyed by fire. Once in 1996 and then again in 2006 by an arsonist who caused 6 billion won ($6 million USD) in damage. Both times it was rebuilt and reconstructed.
There is one other similar command post at Hwaseong Fortress. The other is Dongjangdae (Eastern Command Post).