What influence did foreign nations have on china from 1912-1938?

Western Powers (primarily France, England, USA, Japan and Germany) all owned Chinese concessions, or cities (such as Shanghai, Weihaiwei and Hong Kong), and hence their influence spread throughout China. In the concessions, a modern police force was established and western law used. In 1937, the Japanese invaded Manchuria and hence installed Japanese law and military reform into that area, draughting hundreds of thousands and killing just as many.