Who was the Emperor of Japan during World War II?

Hirohito (29 April 1901 – 7 January 1989) was the 124th emperor of Japan according to the traditional order of succession, ruling over the Empire of Japan from 25 December 1926 until 2 May 1947, after which he was Emperor of the state of Japan until his death. He was succeeded by his fifth child and eldest son, Akihito. Hirohito and his wife, Empress Kojun, had seven children, two sons and five daughters.

In Japan, reigning emperors are known only as "the Emperor." He is now referred to primarily by his posthumous name, Shōwa, which is the name of the era coinciding with his reign; for this reason, he is also known as the Shōwa Emperor or Emperor Shōwa. By 1979, Hirohito was the only monarch in the world with the monarchical title "emperor." Hirohito was the longest-lived and longest-reigning historical Japanese emperor and one of the longest-reigning monarchs in the world.

World War II (WWII or WW2), also known as the Second World War, was a global war that lasted from 1939 to 1945. It involved the vast majority of the world's countries forming two opposing military alliances: the Allies and the Axis. In a state of total war, directly involving more than 100 million personnel from more than 30 countries. World War II was the deadliest conflict in human history, resulting in 70 to 85 million fatalities, with more civilians than military personnel killed.