The Historic Site of Anti-Mongolian Struggle (), also known as the Historic Site of Anti-Yuan Struggle and the Hangpaduri Hangmong Historic Site, is a protected area in Jeju Province, South Korea, that was once the location of an earthen fortress. This fortress, the Hangpadu/Hangpaduri Fortress (also written as Hangpadu(ri)seong), was built in 1271 by the Sambyeolcho rebels, who opposed the surrender by the Goryeo dynasty ruling Korea to the Yuan dynasty following the Mongol invasions of Korea. Built shortly after the Sambyeolcho took over the island of Jeju, the fortress soon became the capital of the rebellion after the Sambyeolcho were defeated elsewhere. Together with the Hwanhaejangseong coastal wall and various village fortifications, the fortress formed part of a defensive system to protect the island. After the Sambyeolcho forces were defeated by a combined Goryeo-Mongol invasion of 12,000 soldiers in 1273, the site eventually fell into disuse.

Hangpadu Fortress was constructed around from Jeju's northern coastline, where the coastal lowlands transition into the mountainous interior. The chosen location provided views of important coastal areas, as well as the Jeju Strait and the Korean Peninsula to the north, where any invasions would originate. The specific site where the fortress was built lay between two rivers, which together with the sloped terrain provided natural defenses. The site also had soil conducive to the building of rammed earthen walls, and was positioned near existing population centers. Two layers of defense were built, creating an almost square inner fortress surrounded by of walls, surrounded by a larger roughly oval area protected by of walls. The inner fortress contained important buildings, including the Sambyeolcho headquarters. An additional wall extended from the north of the outer wall to protect two water sources.

Overall, the design of the fortress is similar to others built during the Goryeo era, including Ganghwasanseong Fortress and Yongjangseong Fortress, which were also built to repel Mongol invasion. Many artifacts found at the site are similar to those found on the mainland, and were likely brought to the island by Sambyeolcho forces. Some of the roof tiles found at the site reflect mainland designs, but are locally made, likely indicating that artisans came to the island with the Sambyeolcho. It is likely that roof tile techniques became more common in Jeju due to their use at Hangpaduri.

The site came to national attention in the late 20th century, when South Korean President Park Chung Hee saw it as a potential symbol of patriotism. In 1976, the site was recognized as a by Jeju provincial authorities, and restoration works occurred from 1977 to 1978 that saw some of the outer walls rebuilt and a monument installed. Some excavations took place in the 1990s, and in 1997 the site was designated as National Historic Site No. 396. Sporadic further research followed, and a dedicated research program began in 2010. Today, the site serves educational and recreational purposes, and is sometimes used to host cultural events.

Location

The protected area is around , of which is the designated historic site. The fortress was built inside an oreum around south from the coastal village of Hagwi-ri. on the western side of the island, where the coastal lowlands meet the more mountainous interior. It lies on a hill between above sea level. The landscape within the outer walls sloped upwards about from north to south. On the eastern and western sides of the site were natural streams, Goseongcheon stream and Sowangcheon stream respectively.

The location was chosen to take advantage of existing topography. The northern, eastern, and western outer walls were built atop already steep terrain; the north atop a steep ridge, and the east and west overlooking drops towards rivers. These sides were thus protected by natural defenses. The position on the oreum meant the fortress was higher than the surrounding terrain, and was thus both defensible and provided a view of potential invasion routes, including naval routes due to its position overlooking the Jeju Strait and Chuja Islands. On clear days islands surrounding the southern end of the Korean Peninsula would also be visible, in the direction of Jindo. The soil at the site was suitable for creating earthen ramparts. There was also easy access to drinking water, and to wild game.

Existing defensive structures, such as Jeju Fortress, were likely seen as too difficult to defend, and having much poorer views of attack from the north. Surrounding the site were six of the sixteen major villages of the island at the time, making it the most populated part of the island. This meant the location could be easily supplied, and had access to six important ports along the northern coast.

Structure

Hangpadu Fortress was the only earthen fortress constructed on Jeju. It was a double structure consisting of an inner complex and wall which was in turn surrounded by a larger area enclosed by a long earthen wall. Both walls are thought to have been at least tall. Their construction involved layers of natural soil, clay, and stones. The stones tend to be around . The inner fortress is sometimes referred to as naeseong (), while the outer walls are sometimes referred to as (go)toseong ().

The inner wall forms a rough square of , consisting of an northern wall, an eastern wall, an southern wall, and an western wall. The base of the inner wall contains a row of stones and rammed earth. The inner fortress is mostly flat, ranging from to above sea level, with a gentle slope northwards. A drainage system moved water towards the east.

The outer earthen wall was historically recorded as being long, however modern research has measured it at . The outer walls follow the slope between the rivers in a somewhat oval shape. The diameter from the southeast to northwest is about , while the southwest to northeast axis is only . It is thought that there were four outer gates. The walls were accessed from the interior side via ramps. The outer wall structure can reach up to wide and tall. It is thought to have a stone base built on excavated bedrock, covered with layers of rammed earth.

The construction process and techniques seems similar to the one used at Ganghwasanseong Fortress, although adjusted for the local topography. Some techniques, such as filling a gap between two rows of stones with rubble, appear to be the same as techniques used at Ganghwasanseong. Other commonalities between the sites include the positioning of timber within the walls and the addition of an interior waterway. Adaptations include those made to accommodate different flooding risks, due to Hangpaduri being built on a hillside rather than on a mountain ridge. If the coastal Hwanhaejangseong is counted as a third surrounding wall for the Hangpaduri complex, the overall Triple wall structure imitates the Kaesong city walls.

The inner fortress was built near two springs. A semi-circular wall, also earthen, extending from the northern outer wall protected these water sources, known as the ongseong () spring and the gushi () spring. The first was reportedly used only by the generals, while the second was used by the rest of the army.

Up to 17 buildings have been identified within the inner fortress. The buildings discovered include watchtowers, a roof tile facility, a well, and a kiln. The buildings were in the north-west of the inner fortress, likely directly connected to each other. They were constructed on platforms to account for the sloped terrain. One is thought to have served as the building for the Sambyeolcho leaders, and might have been larger than the equivalent in Yongjangseong. This building is sometimes also referred to the palace site, although unlike actual palaces (daegulteo, 대궐터) it was not built for royalty. The inner fortress as a whole is also sometimes referred to as the palace site. A watchtower (named ) has been found to the southeast of the fortress, at a high point of the oreum.

The Jangsumul Spring is in legend the site where general Kim T'ongjŏng's footprint remains after he jumped from the earthen walls. In the legend, it is this landing that caused the spring to run year round, and gave the water medicinal properties. The water is credited with protecting the residents of the nearby Goseongri village from an epidemic. Kim T'ongjŏng escaped the fortress with 70 soldiers to fight a final battle at the Bulgeun Oreum, and committed suicide. In some sources, the jump that caused the spring is recorded as the suicide.

The structure of the fort, including building compacted earthen walls with a stone foundation, and inner and outer walls, is of a similar design to that of other fortresses from the Goryeo dynasty period, such as Ganghwasanseong Fortress. Hangpadu may differ slightly in having stones lining both sides of the inner wall. It is likely that similar civil engineers worked on Ganghwasanseong Fortress, Yongjangseong Fortress, and Hangpadu Fortress, during the short period where all fell under the control of the Sambyeolcho Rebellion. Construction elements are also similar to other fortresses built around the same period, such as Gyeongjueupseong and Cheonghaejin. The layout of the Sambyeolcho fortresses, including Yongjangseong and Hangpaduri, resembled the layout of the pre-Mongol capital of Kaesong. This suggests they were intended to provide civilian governance as well as serve military purposes.

Artifacts

Celadon products make up 60% of archaeological items found in the fortress. Much of this was likely produced in the 13th century. Bronzeware, celadon, and ironware from the site resemble similar items found at Samyeolcho fortresses elsewhere, such as from Jindo, and so are thought to have been brought to Jeju by Sambyeolcho forces. Some ceramics appear to be from Yuan China. Iron finds include crockery and armor. Other finds include coins and a stone Gonu board. Some of these coins were found under walls, suggesting they were deliberately buried there, likely as part of a ritual during construction. The Gonu board is made from Jeju rock, indicating local origin rather than coming with the Samyeolcho. 10 cornerstones (, ), or stone hinges, thought to have been located under the fortress' four gates have been found and are displayed at the site. Excavations have uncovered many items from the 13th century, although there are also items from the 12th and 14th centuries. It is possible that some artifacts from the site may date to the 15th or 16th centuries, indicating the site was used long after the Sambyeolcho Rebellion, but this is unconfirmed.

Roof tiles have been discovered with a number of different designs. Some may have come from the mainland, including patterns also found in Jindo, while others are thought to have come from surrounding villages and have patterns that may have been in use before the arrival of the Sambyeolcho. The roof tiles used in the fortress resemble those used in other Sambyeolcho fortresses, suggesting they were made by artisans who retreated to the island with the Sambyeolcho. This was an early example of roof tile production on Jeju, where they were rare at best prior to the Goryeo period. The techniques to create such tiles likely spread from Hangpadu to the rest of the island, even after the defeat of the Sambyeolcho. The inscriptions on the tiles have provided possible insights into the administrative structure of Jeju during that period.

History