Namisum is a tiny half-moon shaped island located in Chuncheon, South Korea, formed as it was inundated by the rising water of the North Han River as the result of the construction of Cheongpyeong Dam (청평댐) in 1944. Its name originated from General Nami (남이장군), who died at the age of 28 after being falsely accused of treason during the reign of King Sejo, the seventh king of the Joseon Dynasty of Korea.