Throughout the late 19th century, Imperial Germany joined other European powers in an imperialist scramble for colonial possessions. As with the other world powers, Germany began to interfere in Chinese local affairs. After two German missionaries were killed in the Juye Incident in 1897, China was forced to agree to the Kiautschou Bay concession in Shantung (now Shandong) to Germany in 1898 on a 99-year lease. Germany then began to assert its influence across the rest of the province and built the city and port of Tsingtao, which became the base of the German East Asiatic Squadron of the Kaiserliche Marine (German Navy), which operated in support of the German colonies in the Pacific.
Britain viewed the German presence in China as a threat and leased Weihaiwei, also in Shantung, as a naval port and coaling station. Russia leased its own station at Port Arthur (now Lüshunkou) and France at Kwang-Chou-Wan. Britain also began to forge close ties with Japan, whose developments in the late 19th century mirrored that of the European imperialist powers as Japan acquired colonial footholds on the Asian mainland. Japanese and British diplomatic relations became closer and the Anglo-Japanese Alliance was signed on 30 January 1902. Japan saw the alliance as a necessary deterrent to its main rival, Russia. Japan demonstrated its potential by its victory in the 1904–1905 Russo-Japanese War, and the alliance continued into World War I.
When the war in Europe began in August 1914, Britain promptly requested Japanese assistance. On 15 August, Japan issued an ultimatum, stating that Germany must withdraw her warships from Chinese and Japanese waters and transfer control of its port of Tsingtao to Japan. The next day, Major-General Mitsuomi Kamio, General Officer Commanding (GOC), 18th Infantry Division, was ordered to prepare to take Tsingtao by force. The ultimatum expired on 23 August, and Japan declared war on Germany.
At the beginning of hostilities, the ships of the East Asia Squadron under Vice Admiral Maximilian von Spee were dispersed at various Pacific colonies on routine missions. Spee's ships rendezvoused in the Northern Mariana Islands for coaling. SMS Emden then headed for the Indian Ocean, while the rest of the squadron made their way to the west coast of South America. The squadron engaged and destroyed a Royal Navy squadron at the Battle of Coronel, before being destroyed at the Battle of the Falkland Islands in the South Atlantic.