Samnyeonsanseong Fortress

On the slopes of Ojeongsan above the town of Boeun, Samnyeonsanseong still raises Silla stone walls that are more than 1,500 years old. Standing below them, you look up at ramparts 13 to 20 metres high and get a real sense of what a Three Kingdoms fortress was like. Silla used it as a forward base against Baekje and Goguryeo, which is why it appears in every account of Korean fortress building.

History: a fortress that took three years

Samnyeonsanseong was built in 470, the 13th year of King Jabi of Silla, and rebuilt in 486 under King Soji. The Samguk Sagi, Korea's oldest surviving chronicle, says it took three years to build, hence the name, meaning "three-year mountain fortress". Another explanation links it to Samnyeon-gun, the old name of Boeun, so sources differ on the origin. Joseon records also call it Ojeongsanseong or Ohangsanseong.

The fortress was a key base when Silla attacked Baekje and pushed towards the Han River valley. Silla troops fighting at the Battle of Gwansanseong were stationed here, and King Muyeol is said to have received envoys from Tang China at the fortress. Records also say that Wang Geon, founder of the Goryeo dynasty, attacked it and had to withdraw. It was designated a Historic Site in 1973 and is on Korea's tentative list for UNESCO World Heritage.

What to see

• The masonry: flat, trimmed stones are laid in alternating horizontal and vertical courses, making the walls extremely solid. Beside the collapsed sections you can clearly see how the layers were built.
• The wall walk: sources give a circuit of roughly 1.7 to 1.8 km. Walking along the top, you look out over the Boeun plain and the ridges beyond.
• West gate site: the first stop after the climb from the car park. Tall walls flank the opening; the gate itself is gone, and only the place where it hung remains.
• Rock inscription and pond site: characters carved into a rock face inside the fortress are traditionally attributed to the master calligrapher Kim Saeng. Below lies the outline of a dried-up pond that once supplied water.

Good to know

Pottery and other finds from Silla through Goryeo and Joseon show that the fortress was used for a very long time. Thousands of ancient tombs are scattered around it, a sign of how important this area was during the Three Kingdoms period. Some stretches of wall have been restored, so new and old stone differ in colour, and comparing the two is part of the fun.

Tripto tips

• Visiting: free and open at all times, with free parking.
• Getting there: it is close to central Boeun and easy to reach by car. From the car park it is about a 10-minute uphill walk to the west gate.
• Time needed: 30 minutes for the west gate area, 1.5–2 hours for a full circuit of the walls. Much of the wall top has no railing, so keep children close.
• Combine with: Beopjusa Temple on Songnisan, about 10 km away, for a full day out. In autumn, when the rice ripens, the golden fields seen from the ramparts are especially beautiful.