It was the Anglo-Japanese Alliance, renewed for the third time in 1911,
which gave Japan formal diplomatic cause for entering the war. On
August 23, 1914 she declared war on Germany.
After a brief struggle, the German forces at the leasehold of Tsingtao,
in Shantung province, surrendered on November 7. A month later the
whole of Shantung province was in Japanese hands. Then followed the
famous Twenty-One Demands on China. On May 25, 1915, at the point of
a gun, China signed treaties and notes incorporating many of these
Twenty-One Demands. Among other things these treaties confirmed
Japan’s newly won position in Shantung province, and extended her
railway and territorial rights in South Manchuria to the end of the
century. American protests helped to block the most sweeping demands,
which would have made China a Japanese protectorate. Meanwhile the
Japanese navy had scoured the Pacific, and had occupied all the German
islands north of the equator.