Even in the early Joseon period, Namhansanseong was viewed as an important strategic point. During the reign of King Taejong, who strengthened and stabilized the royal authority, the issue of repairing Namhansanseong was raised; while, during the reign of King Sejong, and at the suggestion of a chalbang (a post station circuit inspector) of Gyeonggi-do Province, a plan to repair Namhansanseong together with Gyodongsanseong in Ganghwa Island was scheduled after a good harvest, but it is unknown whether the repair work took place or not as there are no relevant records.
Afterwards, the issue of repairing the fortress was discussed again in February 1603 (the 36th year of the reign of King Seonjo), right after the Japanese Invasions of Korea (Imjin Waeran, 1592-1598), and some repair works were carried out in 1621 (the 13th year of the reign of Prince Gwanghae). In addition, large-scale repairs of Namhansanseong were conducted from 1624 to 1626 (2nd to 4th year of the reign of King Injo), which increased the circumference of Namhansanseong to 6,297 steps.
During the Joseon Dynasty, as Namhansanseong served to protect the capital in the event of an emergency, such as an invasion, the Royal Defense Command, which was one of the five army camps, and one of the four magistrate’s offices were stationed inside the fortress.
This view is supported by an ancient record in Namhanji (Gwangju Town Record), written when the fortress was built during the reign of King Injo, which states: “The king ordered the reconstruction of Namhansanseong based on the old site.” On the other hand, the Geography Section of the Annals of King Sejong, written in the early Joseon period, describes the size of Jujangseong as 3,993 steps. According to the Yeongjocheok scale used during the reign of King Sejong, one cheok (or ja) was 31.2 cm, which means that the circumference of the fortress would have been about 7,475 meters, a difference of about 600 meters compared to the measurement recorded in Samguk sagi. The size of Namhansanseong Fortress after its reconstruction in the seventeenth century is given as 6,297 steps. This was measured using the Jucheok scale, and if the length of a jucheok is taken to be 21.5 cm, the total circumference of the fortress would have been 8,123 meters. When comparing this measurement to the length of 17,400 cheok measured using the Pobaekcheok scale during the reign of King Seonjo, if the length of one pobaekcheok is 46.73 cm, then the total circumference of the fortress would have been 8,123 meters, which is nearly identical to the measurement converted into jucheok. Based on these records, it can be understood that the main wall of Silla’s Jujangseong Fortress was almost the same size as that of Namhansanseong, which was repaired and rebuilt during the reign of King Injo.
Certain traces of this magistrate office, such as the monuments to Gwangju’s Magistrates and Chief Magistrates, remain inside Namhansanseong.