 The Japanese Kwantung Army, based in the Kwantung Leased Territory, also had responsibility for safeguarding the South Manchurian Railway and thus had troops stationed in Manchuria, providing material and logistical support for the Fengtian clique.The cooperation initially worked to the mutual benefit of both parties.Zhang provided security for the railroad and Japanese economic interests, suppressing Manchuria's endemic banditry problem and allowing extensive Japanese investments.