HARBIN is situated upon a tributary of the Amur River. A look at the map will reveal the fact that the Amur flows in a general northeasterly direction from this corner of China up through eastern Siberia and debouches into the sea about a thousand miles north of Vladivostok opposite northern Sakhalin. The port at the mouth of this great river is Nikolaevsk.
During the early summer of 1919 river pirates became active in the vicinity of Harbin, and as their numbers increased the local officials of the province presently found themselves powerless against these miscreants. They had no facilities for combating the pirates, and hence in the middle of the summer they appealed to the Central Government for aid. So Peking ordered four gunboats regularly stationed on the Yangtze to proceed to Harbin via Nikolaevsk.