It is a beautiful lake 12 km east of Onjong-ri.
Legend has it that once upon a time a king who had come to take a day’s rest stayed there for three days as he was fascinated with the scenery of the lagoon, hence the name. Crystal-clear water, rocky hills around the lagoon and thick foliage add to the scenic attraction of the place.
In this area are Wau Islet, the site of Sason Pavilion, Tanso Rock and Mokson Rock, and around it are Janggun Rock, Pongnae Rock, Ryonhwa Rock and Kumgang Gate. It is a good place for boating and sightseeing tour along the excursion road linking the hills around the lagoon. At the bank of the lagoon is a restaurant called Tanphung. The lagoon is 5.8 kilometres round and 9-13 metres deep at the maximum.