A Study on the Earthen Fortress of Gayari, Haman: Focused on the Construction Techniques and Structures

The Earthen Fortress of Haman Gayari are the remains of Earthen Fortress representative of Aragaya along with the Malisan Ancient Tombs, which were recently designated as a UNESCO World Heritage sites. The sites are located in the hills of Gayari, which offers an excellent view of most of the Hamancheon Stream basin. Although references to the sites have been confirmed since the Joseon Dynasty, the archaeological investigation began in 2018 and continues until 2022. As a result of the investigation, Earthen Fortress, which was built using formworked earth techniques, was confirmed for the first time in the Gaya area, and the interior space of a Earthen Fortress, one building with an elevated floor, seven buildings with pit-dwelling, four pits, and the pillar hole groups, archaeologically proving it was a living space for the Aragaya ruling class. In particular, Earthen Fortress, which has a total circumference of about 2.4 kilometers, is the largest among the Earthen Fortress of Gaya culture, and is on par with the royal fortresss of the Three Kingdoms, such as Buso Fortress in Buyeo and Wolseong Fortress in Gyeongju. The construction technique of the Fortress shows a difference between the first wall and the repaired, and the expanded wall. The first wall was built using the formworked earth techniques and the construction method, which is different from the formworked earth techniques of Hanseong Baekje. The repaired and expanded wall, embankment techique was used and the defense power was reinforced by installing a wooden fence. The structure of the Earthen Fortress consists of inner fortress and outer fortress, and shows a unique pattern connecting the Gayari Embankment from the northeast of the outer fortress. Also in the south of inner fortressthere is a presumptive embankment sites, which is also observed in Japanese colonial era photographs and intellectual maps. And the structure of the wall changes with time, and it changes from earthen fortress to a wooden fortress. Wooden Fortress is again divided into the slope barrier stage and the top barrier stage, and in the latter case, there is a possibility that the wall was raised once more. The construction techniques and structures of this sites do not simply show Aragaya's civil engineering technology, but it is a clue to understanding exchanges with neighboring countries and an important evidence to gauge Aragaya's national power. And around the Gayari sites, there are many major sites of Aragaya, including Bongsan Fortress, West ridge of the Malisan Ancient Tombs, Seonwang Ancient Tombs, Deokjeon Ancient Tombs, Pildong Ancient Tombs, and Gayari Embankment sites, so it is highly likely that Gayari Earthen Fortress was the royal fortress of Aragaya.