Analysis of information sources in references of the Wikipedia article "Siege of Tsingtao" in English language version.
There were problems too of "friendly fire" at least from the Japanese... After this tragedy, the soldiers started to wear a piece of white cloth on their helmets as a means of identification. A better solution came when British soldiers were issued with a Japanese style smock which they wore over their uniform. This at least stopped Japanese sentries firing long enough for them to identify the British as friendly.
