Site of Chomsongdae Observatory of Koguryo
Astronomy developed considerably in Koguryo.
Dr. Kim In Chol, Section Chief of the Archaeological Institute under the Academy of Social Sciences, said that the high development of astronomy in Koguryo is unthinkable apart from the Chomsongdae Observatory, the base for observing the sun, moon and stars, and the centralistic and systematic observation of the state, and continued:
"Koguryo built the Chomsongdae Observatory for astronomical observations and the officials in charge of the astronomical observations made observations day and night in all seasons.
Such historical fact is proved well through the site of the Chomsongdae Observatory unearthed around the Anhak Palace, the royal palace at the time of the Koguryo Dynasty."
The site of the Chomsongdae Observatory of Koguryo is in today's Taesong District of Pyongyang.
It covers a wide area of about 380 square metres. Most of the superstructure was destroyed not to recognize its shape, but the substructures are preserved comparatively as they were.
The site largely consists of the tetragonal main facility and the heptagonal auxiliary facility around it.


The foundation is about 1.3 metres deep. It is solid enough to support about 1,000 tons of weight from an architectural point of view.
Imagining the superstructure on the basis of the archaeological materials on the site, it is possible to guess that a stone structure for astronomical observations existed there.
The fact that there is the Pyongyang Observatory on the ridge opposite the site shows that the place is very favourable for astronomical observations.
The site of the Chomsongdae Observatory of Koguryo built in the first half of the 5th century is of great significance in showing the high development of astronomy in Koguryo.