A century ago China was at the height of its warlord period. The nascent Republic of China had 26 prime ministers in 12 years as one warlord after another gained ascendency in their internecine struggles.

Little wonder, then, that China remained neutral as the First World War raged, signing up with the Allies only in the last year of the conflict. The Japanese too, though formally allied with the Entente powers, provided little practical assistance. Japan invaded Tsingtao and defeated the German garrison in one of the war’s first battles, but after that Japan declined to provide much support when importuned by its hard-pressed allies. Late in the war, once the defeat of the Central Powers seemed likely, Japan supplied some war materiel under the terms of secret treaties assuring British and French support for its colonial ambitions after the war. Its aim was to be anointed Germany’s successor in control of its Pacific colonies, including continued occupation of Tsingtao.