Usan

Usan-guk, or the State of Usan, occupied Ulleung-do and the adjacent islands during the Korean Three Kingdoms period.

Usan-guk rarely entered into historical records, but appears to have continued a largely autonomous existence until its loss of independence to Goryeo in 930.

[2][3] Earliest records that appear in the Records of the Three Kingdoms indirectly attest the existence of the kingdom, which says "When Wang Qi(王頎) (of Cao Wei) has come to Okjeo to conquer gung (Dongcheon of Goguryeo), he asked a local man whether there are people living in the east sea, and the man replied there are people living in an island that exists in the eastern seas, and they select a girl to put in the ocean every July.

"[4][5] In Samguk Sagi, it is said that because of general Isabu's threats with wooden lions, Usan chose to be a vassal state to Silla in 512.

[6][7] In Goryeosa, it is recorded that Usan requested to be submitted under the rule of Goryeo in 930 by sending Baekgil and Todu.