Namporu, the southern sentry post, is a wooden structure built on top of square turret. The wooden structure is known as a poru while the square turret is known as a chiseong.
There are five similar structures at Hwaseong Fortress. All are constructed of brick. They are positioned on turrets that protrude beyond the fortress walls. This position allowed for easy attacks by artillery on enemies below.
The main purpose of this structure was to guard the area around Paldalmun Gate, Seonamgangnu, and the Yongdo (Passageway).
Construction on the structure completed on July 9, 1796.