During which conflict did Emperor Hirohito rule Japan?

Emperor Hirohito ruled Japan during World War II, which spanned from 1939 to 1945. His reign, which began in 1926 and lasted until his death in 1989, encompassed a significant period of Japanese history, including its militarization and eventual involvement in global conflicts. During World War II, Hirohito was a controversial figure; while he was seen as a symbol of Japanese unity, there were debates about the extent of his involvement in military decisions. His role during the conflict is critical for understanding the dynamics of Japan's expansionist policies and eventual capitulation, leading to significant changes in Japan's political landscape post-war.

Other conflicts listed, such as World War I, the Korean War, and the Vietnam War, occurred outside of Hirohito's direct influence as a ruling emperor or afterward, marking them irrelevant in this context.