Beginning 1 October 1903, most mail between Kiautschou to Germany was transported via the Trans-Siberian Railway. This routing was unavailable from 1 January 1904 to 11 February 1907 due to the Russo-Japanese War, and was permanently terminated upon the outbreak of World War I.
Mail sent by rail from Tsingtau on 21, 24, & 28 July 1914 was still transiting Russia when the war began, and was seized by Russia and returned to Shanghai. This mail was then delivered by other means, typically by routing it through the U.S. Some, but not all, mail pieces returned to Shanghai bear a Russian censor mark. Additionally, some, but not all, received a transit mark showing the date of arrival in Shanghai.
Four types of Russian censor marks are known. Two are known on items from Kiautschou and the German Post Offices in China. The third and fourth are only known on items from the German Post Offices in China, but use on items from Kiautschou is theoretically possible, as items from Kiautschou and the German Post Offices in China were usually transported together.