On Sept. 2, 1923, widespread fires caused by the Great Kanto Earthquake the previous day raged out of control in Tokyo. On that day, as Gonbei Yamamoto was preparing to install his cabinet as the new prime minister, acting premier Kosai Uchida imposed martial law in central parts of the capital and other areas as panic and false rumors of a "Korean riot" spread, which would lead to the massacre of ethnic Koreans and others.