The exact date of the fortress's construction is unknown but according to the Haman Eupji (Haman Township Records), this fortress is recorded as being an old site of the ancient Gaya Kingdom. Its design follows the typical style of the fortresses from the Three Kingdoms period. Meanwhile, at the foot of the mountain on the lower northern slopes lies Marisan Mountain and clusters of tombs from the same era. Considering the close relationship between fortresses and tombs since ancient times, it is presumed that this fortress is a relic from the Gaya period.

From the north, Seongsan Mountain appears as an isolated hill and except for the southwestern ridge that stretches gently, the other three sides have relatively steep slopes. Inside the fortress, the terrain is slightly concave and flat and much of the area is now used as farmland.

The fortress wall was constructed along the ridge at the mountain's summit using natural stones or worked stones to build stone ramparts. A well-preserved section of the wall about 1 meter high remains on the northeastern side, while the eastern side has well-preserved stone walls about 6 to 7 meters in height. The fortress wall was built by laying slab-shaped stones and rectangular or square-shaped stones horizontally. The exterior has a reinforced structure. The inner area of the fortress covers approximately 102,500 square meters.

Recent academic excavation of the fortress confirmed the locations of the eastern and southern gates, and additional structures, such as drainage facilities, a pond, building sites and other important artifacts, including pottery such as gobae and short-necked jars, roof tiles featuring goblin faces, amkiwa (flat roof tiles), sukiwa (round roof tiles), decorated tiles and inscribed wooden tablets with significant historical value. The fortress was designated as Historic Site No. 67 on January 21, 1963.

Location

• Gwangjeong-ri, Gaya-eup, Haman-gun, Gyeongsangnam-do, Republic of Korea