Earthen Fortification in Jeongbuk-dong

In the middle of open farmland beside the Mihogang River, just north of Cheongju, a low square rampart of packed earth encloses a grassy field. Its circuit of about 675 m survives almost in its original shape, and with a few pine trees on the walls and a huge open sky it has become a favourite spot for sunset photographs. The fact that nobody is quite sure when or by whom it was built only adds to the interest.

Who built it, and when?

Unlike most Korean fortresses, this one stands on flat ground rather than a hilltop. A Joseon-era record of nearby Sangdangsanseong tells how Gungye made Sangdangsanseong his capital and Gyeon Hwon took it and built an earthen fort nearby, which would date this site to the Later Three Kingdoms of the 9th–10th centuries. However, the finds inside, the layout and the location point to a much earlier origin, probably the early Three Kingdoms period (around the 2nd–3rd centuries), and some sources place it even before the Common Era.

Excavations found house sites, post holes, a road and stone heaps inside, and outside the walls traces of a moat that once ringed the fort. Because it is a rare example of how early earthen forts were built on the Korean Peninsula, it was designated a national Historic Site in 1999.

Walking the walls

• The square rampart: about 3.5 m high and 8–13 m wide, with a flat top you can walk along. Even at a slow pace a full circuit takes only about 15 minutes.
• Four gate sites: gaps mark where gates stood on all four sides. At the south and north gates the walls overlap and are offset so attackers could not charge straight in.
• Corners and bastions: the corners and the middle of each wall bulge slightly outwards; defenders used these to watch the walls and strike at attackers from the side.
• Pines and fields: pine trees on and inside the walls stand out against the flat fields. The interior is lawn and easy to walk.

The fortress at sunset

With no tall buildings nearby, the sky here is wide open. This is why the site became known for backlit silhouettes of the pines and people on the rampart at sunset. Arrive on a clear late afternoon, walk the circuit, and settle on the western wall as the sun goes down.

A fort on the plain, not on a hill

Most old Korean fortresses are stone walls on mountain tops, so a neat earthen square in the middle of farmland feels unusual at first sight. The walls were built by ramming earth down layer by layer, a technique that has let them survive for close to two thousand years. The broad fields and the waterway of the nearby Mihogang River (renamed from Mihocheon in 2022) were probably what drew the builders here.

Tripto tips

• Visiting: there is no gate or ticket; the site is open 24 hours and free, and there is a car park.
• Time needed: 30 minutes to an hour for a circuit and photos.
• When to go: clear late afternoons for the sunset; May–June when the fields are green, or October when the rice turns gold. There is almost no shade, so summer middays are hot, and there is no lighting after dark.
• Getting there: the site lies in the fields by the Mihogang River, north of central Cheongju. Public transport is awkward, so a car or taxi is best. The address is 353-2 Jeongbuk-dong, Cheongwon-gu, Cheongju.
• Combine with: on the way back into town, add Cheongju Early Printing Museum, Cheongju National Museum or Sangdangsanseong Fortress for a day of Cheongju history.