Japan's rapid industrialization and militarization under the slogan Fukoku Kyōhei (富國強兵, "Enrich the Country, Strengthen the Armed Forces") led to its emergence as a world power and the establishment of a colonial empire. Economic and political turmoil in the 1920s led to the rise of militarism, eventually culminating in Japan's membership in the Axis alliance and the conquest of a large part of the Asia-Pacific region.
Japan's armed forces initially achieved large-scale military successes during the Second Sino-Japanese War (1937–1945) and the Pacific War. However, after suffering many defeats and following the Soviet Union's declaration of war against Japan and invasion of Manchuria, and the atomic bombings of Hiroshima and Nagasaki, the Empire surrendered to the Allies on August 15, 1945. A period of occupation by the Allies followed the surrender, and a new constitution was created with American involvement in 1947, officially bringing the Empire of Japan to an end. Occupation and reconstruction continued well into the 1950s, eventually forming the current nation-state whose full title is the "State of Japan" or simply rendered "Japan" in English.
The Emperors during this time, which spanned the entire Meiji and Taishō, and the lesser part of the Shōwa eras, are now known in Japan by their posthumous names, which coincide with those era names: Emperor Meiji (Mutsuhito), Emperor Taishō (Yoshihito), and Emperor Shōwa (Hirohito).
The historical state is frequently referred to as the "Empire of Japan", the "Japanese Empire", or "Imperial Japan" in English. In Japanese it is referred to as Dai Nippon Teikoku (大日本帝國), which translates to "Greater Japanese Empire" (Dai "Great", Nippon "Japanese", Teikoku "Empire"). This is analogous to Großdeutsches Reich, a term that translates to "Greater German Empire" in English and Dai Doitsu Teikoku (大独逸帝國) in Japanese.
This meaning is significant in terms of geography, encompassing Japan and its surrounding areas. The nomenclature Empire of Japan had existed since the anti-Tokugawa domains, Satsuma and Chōshū, which founded their new government during the Meiji Restoration, with the intention of forming a modern state to resist Western domination.