Kaesong Chomsongdae (an astronomical and meteorological observatory) testifies to the high level of the astronomical and meteorological survey in the period of Koryo.

   It is situated west of Manwoldae, the site of the Koryo Royal Court. Through its location and the record in Koryosa, it is recognized to have been built in the early Koryo dynasty when Yongyong Palace was built in Manwoldae.

   Its platform is 2.8 m high and 2.6 m wide. Five stone columns were set up on the four corners and at the centre.  These columns were linked by five beams, and several flagstones were placed above them to form the upper part of the platform. The linking parts of the beams were grooved and iron plates were inserted into them so that the parts would not deform.

   In Koryo, there were government organs like Thaebokgam and Thaesaguk for the astronomical and meteorological observation.

   From 1105 to the end of Koryo, more than 50 times of sunspots were recorded, in addition to the detailed records on the solar eclipse, planets screened by the moon, comets and meteors, and other special celestial phenomena.

   Kaesong Chomsongdae is a precious relic showing the level of astronomical survey of our country at that time and the high stone-processing technique and architecture of the Middle Ages.

   It was inscribed on the World Heritage list in Juche 102 (2013) as an excellent astronomical and meteorological observatory in the period of Koryo.