"Mainland Japan" is a term used to distinguish Japan's core land area from its outlying territories. "Mainland Japan" was an official term in the pre-war period, distinguishing Japan proper from its overseas territories in the Far East, such as Japanese Taiwan, Japanese Korea, Karafuto, the South Seas Mandate, and the Kwantung Leased Territory. After the end of World War II, its usage became less common and lost its previous legal significance.