Usan

Usan-guk, or the State of Usan, occupied Ulleung-do and the adjacent islands during the Korean Three Kingdoms period. According to the Samguk Sagi, it was conquered by the Silla general Kim Isabu in 512.^[1] He is said to have used wooden lions or tigers to intimidate the residents into surrendering. It has been written that the alias of Usan-guk is Ulleung-do. 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.^[8] In 1018, when Usan was severely affected by Jurchen invasions, the Goryeo king sent Lee Won Gu with farming equipment, and asked the locals of Usan who have fled from those invasions to return to their lands.^[9] Usan was finally abolished and fully incorporated in 1022 as all of the refugees from Usan were settled to the region of Yeju.^[9]

• Usan
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  Joseon map (1530): Ulleungdo (鬱陵島) and Usan (于山島)
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  廣輿圖 (Gwang Yeodo,1737-1776)
  This map showed Ulleungdo with a small island off its eastern shore labeled as "the so-called Usando" (所謂 于山島).
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  Kim Jeong-ho "Daedongyeojido" (1861): East of Ulleungdo (鬱陵島) and Usando (于山)
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  A map by Korean Empire: Ulleungdo (鬱陵島) and Usan (于山)