Emperor HIrohito had a big role in Japan's attacks on not only other Asian countries during World War II, but against the United States as well. The most notable of these attacks was the Pearl Harbor attack on Dec. 7, 1941.
Hirohito allied Japan with Nazi Germany and Fascist Italy in 1940. He signed a pact with the other leaders promising to support the other countries when needed. This pact came to fruition in 1941 with Pearl Harbor. Although the United States had not yet entered the war, this attack propelled them into World War II with a vengeance. While the United States fought Germany on one front, it battled Japan on another as the later settled into several island countries in Southeast Asia, including the Philippines, New Guinea, the Dutch East Indies and British Singapore. Despite the United State's position of power in the region in 1942, Hirohito refused to surrender until the atomic bombs were dropped on Hiroshima and Nagasaki in Aug. 15, 1945. Days later Hirohito admitted defeat.
World War II devastated Japan. Hirohito's power was stripped from him, and he became nothing more than a figurehead with the real power going to elected officials. He remained as monarch until his death in 1989.