The Allies occupied Japan until 1952 , during which a new constitution was enacted in 1947 that transformed Japan into a constitutional monarchy . After 1955 , Japan enjoyed very high economic growth , and became a world economic powerhouse . Since the 1990s , the Lost Decade had been a major issue , such as the 1995 Great Kobe-Osaka earthquake and Tokyo subway sarin attack . In 2004 , Japan sent a military force as part of the international coalition forces during the Iraq War
Tokyo subway sarin attack
Tokyo subway sarin attack
History of Japan