World War I: Siege of Tsingtao: A Japanese fleet commanded by Vice Admiral Sadakichi Kato imposes a blockade along the whole coastline of German Tsingtao, initiating the Siege of Tsingtao.

The siege of Tsingtao was the attack on the German port of Qingdao (Tsingtao) from Jiaozhou Bay during World War I by Japan and the United Kingdom. The siege was waged against Imperial Germany between 27 August and 7 November 1914. The siege was the first encounter between Japanese and German forces, the first Anglo-Japanese operation of the war, and the only major land battle in the Asian and Pacific theatre during World War I.

Baron Katō Sadakichi was an admiral in the Imperial Japanese Navy during World War I. His brother, Katō Yasuhisa, was a general in the Imperial Japanese Army, and his adoptive son was the biological son of Admiral Dewa Shigetō.

Qingdao is a prefecture-level city in the eastern Shandong Province of China. Located on China's Yellow Sea coast, Qingdao was long an important fortress. In 1897, the city was ceded to Germany. For the Germans Qingdao (Tsingtau) was a strategic trade center, port and base for its East Asia Squadron, allowing the German navy to project dominance in the Pacific. In 1914, following the outbreak of World War I, Japan occupied the city and the surrounding province during the Siege of Tsingtao. In 1915, China agreed to recognize Japan's special position in the territory through what became known as the Twenty-One Demands. In 1918, the Chinese government, under the control of the warlord Duan Qirui, secretly agreed to Japanese terms in exchange for a loan. Following the First World War, during the Paris Peace Conference, Japan secured agreements with the Allied powers to recognize its claim to the areas in Shandong, which included Qingdao, previously occupied by Germany. In 1922, Shandong reverted to Chinese control following the United States' mediation during the Washington Naval Conference. Today, Qingdao is a major nodal city of the Belt and Road Initiative (BRI) that connects Continental and East Asia with Europe. It has the highest GDP of any city in the province.