Tokyo blackout hit 350,000 households and offices. The cause of the blackout is still unclear, the investigation is underway.
Tokyo Electric Power Co. noted that there was black smoke detected at its unmanned power substation located in a in a business district of Niiza city, near Tokyo. However, there is no evidence that the smoke at the substation is related to the incident.
Among the governmental offices that temporarily lost power was Tokyo's Metropolitan Police Department, the Land and Transportation Ministry and the Foreign Ministry.