512 establishments

Usan-guk or the State of Usan () was a statelet that occupied the island Ulleungdo and several adjacent islands in Korea during the Three Kingdoms period. According to the Samguk sagi, it was conquered by the Silla general Kim Isabu in 512. 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.