The State of Japan (Japanese: 日本国, Nippon-koku), colloquially known as Japan (日本, Nippon), is an island nation located in East Asia. Japan is a constitutional monarchy headed by an Emperor. Japan sided with the Axis Powers during World War II, in which the Empire of Japan was able to expand across Asia and Oceania. The war came to an end in Auguast 1945 following the dropping of American nuclear bombs on Hiroshima and Nagasaki (the only instances in which nuclear weapons were used against a nation). Japan would gradually emerge from the war as an American-backed capitalist nation during the Cold War, with the Japanese economy becoming one of the largest on Earth.