Aug 3, 1635: The third of the Tokugawa shoguns, Iemitsu, establishes the system of alternate attendance (sankin kotai) by which the feudal daimyō are required to spend one year at Edo Castle in Tokyo and one year back home at their feudal manor, while their families remained in Tokyo as virtual political hostages. (Traditional Japanese Date: June 21, 1635).
Aug 30, 1974: Powerful bomb explodes at the Mitsubishi Heavy Industries headquarters in Marunouchi, Tokyo, Japan. 8 killed, 378 injured. Eight left-wing activists are arrested on May 19, 1975 by Japanese authorities.