The Empire of Japan, also referred to as the Japanese Empire, Imperial Japan, or simply Japan, was the Japanese nation-state that existed from the Meiji Restoration in 1868 until the enactment of the reformed Constitution of Japan in 1947. From 29 August 1910 to 2 September 1945, the Empire of Japan included the naichi and the gaichi. It also ruled colonies such as Kwantung, South Seas, Mantetsu, and its concessions. The naichi was under Japanese direct rule while the gaichi was not, however both were parts of the empire. In the closing stages of World War II, with Japan defeated alongside the rest of the Axis, on 2 September 1945 the formalized Japanese Instrument of Surrender was issued in compliance with the Potsdam Declaration of the victorious Allies; and Japanese territory was immediately much reduced when lost Taiwan, Korea, Kuril and Karafuto as it is today.

The Meiji Restoration, referred to at the time as the Honorable Restoration , and also known as the Meiji Renovation, Revolution, Regeneration, Reform, or Renewal, was a political event that restored practical imperial rule to Japan in 1868 under Emperor Meiji. Although there were ruling emperors before the Meiji Restoration, the events restored practical abilities and consolidated the political system under the Emperor of Japan. The goals of the restored government were expressed by the new emperor in the Charter Oath.