Sangdangsanseong Fortress

Look east from central Cheongju and you can see a band of wall wrapped around the top of Sangdangsan. Sangdangsanseong is a valley-enclosing mountain fortress whose stone walls follow the ridges around an entire basin, and it is the city's best-known historic structure. From the walls you look out over Cheongju and as far as Cheongju International Airport, and a village inside the fortress is a good place for a break.

History: a Baekje name and Joseon walls

The name "Sangdang" appears to come from Sangdang-hyeon, the old Baekje name for Cheongju. The first fortress here is thought to have been an earthen one, and inscribed roof tiles found outside the south gate link it to Seowongyeong, a regional capital of Unified Silla. One tradition says it was built by the father of the Silla general Kim Yu-sin.

Through Goryeo and Joseon it guarded the route linking the south-eastern and south-western provinces with Seoul. It was repaired in 1596, during the Japanese invasions, and in 1716 the walls were rebuilt on a large scale in dressed granite, giving the fortress its present form. The names and ranks of the men in charge of the work are carved into the gate stones. About 3,500 soldiers and warrior monks are said to have been stationed here to guard and maintain it. It was designated a Historic Site in 1970.

What to see

• Gongnammun (south gate): the main gate, an arched stone opening topped by a wooden gate tower, restored in 1977.
• Mihomun (west gate): the most unusual of the three gates. Walls project on both sides outside, and you must turn inside the gate to reach the tower.
• Jindongmun (east gate) and the hidden gates: along with the east gate, two secret side gates survive. The south one is only 166 cm wide and 172 cm high.
• East command post and pond: Dongjangdae, where troops trained, was rebuilt in 1992. The reservoir inside the fortress was made after the original sluice was washed away by a flood.

Good to know

People still live in a village inside the walls. Its hanok restaurants serve savoury pancakes and traditional rice wine, and walking the walls before eating here has long been a favourite Cheongju outing. Sources give the circuit as anything from 4.1 to 4.4 km, and a path follows the walls all the way round and back down into the fortress.

The gate stones record the names of Chungcheong army commander Yu Seong-chu and his successor Yi Tae-mang, who supervised the work of 1716–1719, and note that two temples, Guryongsa and Namaksa, and a hidden gate were added inside the fortress the following year. The west gate, Mihomun, was dismantled and repaired in 2014–2015; the original west gate stood 38 m further out. From the south hidden gate, a ridge path of about 1.7 km leads down to the Geotdaesan beacon, and defenders used this gate to slip behind enemy lines or watch the road to the south.

Tripto tips

• Visiting: free, open at all times, with parking. Culture and tourism guides are on site and give explanations in Korean.
• Time needed: a full circuit takes about 2–3 hours. For a shorter walk, go from Gongnammun to the west gate and then down into the village.
• When to go: fresh spring green and autumn colours make the best walking seasons. The walls have little shade, so in summer go in the morning or late afternoon.
• Combine with: Sangdangsanseong Recreational Forest below the fortress, with more forest trails to explore.