Poru, also known as artillery pavilions, protrude outward and were utilized for attacking enemies by housing artillery called ‘Hwapo’ within them. These pavilions are structured across three floors. The lower level was designated for artillery storage, while the upper levels served as vantage points for soldiers to surveil the surrounding area and engage the enemy using firearms and arrows. Soldiers fired upon approaching enemies through holes in the fortress walls. Hwaseong Fortress features a total of five artillery pavilions, with Namporu situated to the south of the fortress.

These artillery pavilions were distinctive facilities introduced during the latter half of the Joseon Dynasty, scarcely found in traditional settlements and mountain fortresses prior to the construction of Suwon Hwaseong. Among the five artillery pavilions within Hwaseong Fortress, Namporu remains in the best original condition.