 The "Dong'guk yeoji seungnam" (동국여지승람, "Augmented Geography Survey of the Eastern Nation (Korea)", 1481) defining Korea's territory, stated that "Usando and Ulleungdo are under the jurisdiction of Uljin-hyeon of Gangwon-do as an administrative unit.However, it also mentions that the tree and the beach could be clearly seen on a fine day.The 1531 revision of this book includes the ("Map of the Eight Provinces"), showing two separate islands of Usan-do and Ulleung-do in the middle of the Sea of Japan.