Ganghwa Outer Fortress

Along the east coast of Ganghwa Island, facing Gimpo across the narrow Yeomha channel, runs a long defensive wall built and rebuilt by the Goryeo and Joseon dynasties. The Ganghwa Outer Fortress (Ganghwa Oeseong) was raised by the Goryeo court, which had moved its capital to Ganghwa to escape the Mongol invasions, to stop the enemy crossing the water. It stretches about 23 km, from Jeokbuk Fort in the north to Chojijin in the south. Walking past its surviving walls, forts and coastal paths, you get a real sense of the island's role as the last line of defence for the capital.

From Goryeo sea defence to Joseon brick wall

In 1232 King Gojong of Goryeo moved the capital to Ganghwa Island to escape the Mongols. The island's capital had inner, middle and outer walls: the inner wall is today's Ganghwa Sanseong Fortress, while the outer wall followed the east coast. It was the key defence against a Mongol crossing. Sources give its construction date as 1233 or 1237.

In the Joseon period, Ganghwa was the planned refuge for the king in wartime, so the outer wall was repeatedly maintained. It was repaired in 1618, and after it collapsed during the Qing invasion of 1636 it was rebuilt in stone under King Sukjong, with small forts known as dondae added along it. Because rain kept washing the earth away, the Ganghwa governor Kim Si-hyeok had it rebuilt in brick from 1743 into the following year. Old records describe a wall 20 cheok high and 5 wide, with six gate towers – Johaeru, Bokparu, Jinhaeru, Chamgyeongnu, Gongjoru and Anhaeru – six hidden gates and 17 water gates.

What to see

• The brick wall: South of Odu Fort a stretch of the brick wall rebuilt under King Yeongjo survives. Large stones laid on the tidal mud form the core of the wall, with several courses of brick on top. Together with Hwaseong Fortress in Suwon, it is a key example for the study of Joseon brick fortifications.
• Wolgot Fort and Yeonmijeong: On the northern stretch of the wall, in Wolgot-ri, stands Wolgot Fort, reorganised under King Sukjong, and inside it the pavilion of Yeonmijeong, named after the way the waters of the Han and Imjin rivers meet and split like a swallow's tail. In 1627, during the first Manchu invasion, King Injo agreed a humiliating "brotherhood" treaty with the Later Jin here. From the fort you look across the Jogang estuary to North Korean territory close by.
• Jinhaeru gate site: The site of the Jinhaeru gate tower was confirmed by excavation and added to the protected Historic Site in 2014.

Tripto tips

• Walking: Course 2 of the Ganghwa Nadeulgil, the "Hoguk Dondae-gil", follows the coast once guarded by the outer wall for 17 km, from Gapgot Fort via Yongjinjin, Yongdang Fort, Hwado Fort, Odu Fort, Gwangseongbo and Deokjinjin to Chojijin. The full walk takes nearly six hours, so you may prefer a section such as Odu Fort to Gwangseongbo.
• Time needed: 30 minutes for the brick wall near Odu Fort, and a separate 30 minutes to an hour for Wolgot Fort and Yeonmijeong.
• Getting there: The remains are scattered along the coast, so a car is the easiest way to move between them. Wolgot Fort is about 4 km north-east of Ganghwa town.
• Good to know: Yeonmijeong lies close to a military border zone and is watched over by Marine Corps posts. Always follow any signs or instructions restricting access.