Since the founding of Joseon in 1392, a retrieval policy was instituted to prevent people from residing in Ulleungdo. The purpose of this policy was to protect islands and coastal regions from Japanese invasion and repatriate fugitives who had fled to evade compulsory labor and military service. Although Ulleungdo had effectively become an uninhabited island as a result of this policy, Dokdo and Ulleungdo were inducted into Uljin County in 1432, and officials were dispatched for purposes of administration. The main purpose of the retrieval policy was to protect the island residents rather than to relinquish sovereignty.
The Annals of King Sejong Geographical Records states, “Usan and Mureung islands are in the middle of the sea directly east of Uljin County. The two islands are close enough that the other is visible on a clear day. They were referred to as the State of Usan in the Silla period.” “Usando” and “Mureungdo” described in this record refer to modern-day Dokdo and Ulleungdo, and the two islands are indicated as having been the State of Usan. Similar records appear in the
Complete Conspectus of the Territory of the Eastern Country (Dongguk yeoji seungnam, 1481) and the
New and Expanded Complete Conspectus of the Territory of the Eastern Country (Sinjeung Dongguk yeoji seungnam, 1530) that attest to the Joseon government having sovereignty over the islands. The
Compilation of Reference Documents on the Eastern Country (1770) recorded that “Ulleung and Usan are part of the State of Usan. Usan is referred to as Songdo by Japanese.” This fact is repeated in
The Annals of King Sukjong (1728),
Notes on Joseon’s Frontiers (
Ganggye go, 1756),
Essentials of Governance, Comprehensive Study of Civilization, Revised and Expanded, and other observational sources. Therefore, Usando, otherwise known as Dokdo and as Matsushima during Japan’s Edo period, has been considered Korean territory since the Three Kingdoms Period.