Germany–Japan relations Kaiserliche Marine in and around Chinese waters. Japan, eager to reduce the presence of European colonial powers in South-East Asia, especially on China's coast, sent Germany an ultimatum on 14 August 1914, which was left unanswered. Japan then formally declared war on the German Empire on 23 August 1914 thereby entering the First World War as an ally of Britain, France and the Russian Empire to seize the German-held Caroline, Marshall, and Mariana Islands in the Pacific. The only major battle that took place between Japan and Germany was the siege of the German-controlled Chinese port of Tsingtao in Kiautschou
History of Germany during World War I History of Germany during World War I During World War I, the German Empire was one of the Central Powers that lost the war. It began participation in the conflict after the declaration of war against Serbia by its ally, Austria-Hungary. German forces fought the Allies on both the eastern and western fronts, although German territory itself remained relatively safe from widespread invasion for most of the war, except for a brief period in 1914 when East Prussia was invaded. A tight blockade imposed by the Royal Navy caused severe food shortages in the cities, especially in the winter of