During the times of 1914-1918 Japan joins allied forces in WW1. The Great Kanto Earthquake devastates Tokyo and Yokohama. 1926 - 1989 Known as the Showa period. The second Sino-Japanese War begins. The Pacific War starts.
Japan surrenders after two atomic bombs are dropped over Hiroshima and Nagasaki.
The new Constitution is promulgated in 1946. The Allied Occupation of Japan ends. In 1956Japan becomes a member of the United Nations. Japan begins to have normal relations with China. In 1973 Japan faces an oil crisis.