 Japan sent Germany an ultimatum on 15 August 1914, which went unanswered; Japan then formally declared war on Germany on 23 August 1914 in the name of the Emperor Taishō.As Vienna refused to withdraw the Austro-Hungarian cruiser from Qingdao, Japan declared war on Austria-Hungary, too, on 25 August 1914.Japanese forces quickly occupied German-leased territories in the Far East.