These inscribed characters are said to have been written and inscribed by Choi Chi-Won, who was a great poet and scholar of the late Silla period. According to a tradition, when he was going to go to Gayasan mountain to escape from adverse political circumstances, he was struck by the beautiful scene made by the sea, clouds, moon and hills here, and thus inscribed three letters, Hae (sea), Un (cloud), and Dae (hill) on this rock. It is uncertain that these characters were personally inscribed by him, however it is obvious that the inscribed characters had existed already in the early fourteenth century. Today, the middle character, Un, is severely worn down, eroded by the wind and waves.