Seochulji means the pond where the letter came from. King Soji, the 21st ruler of Silla, was on a trip to Dongnamsan Mountain and saw a strange sight in which an older man appeared in the middle of a pond.
The old man handed the king an envelope containing a letter, and inside it was the phrase "Shoot the Geomunto(Korean musical instrument)" With this in mind, the king returned to the palace and shot the harp with a bow, saving his life from the assassin hiding inside. There is also a promenade around the pond, making it an excellent place to stroll.