 After 1940, the Japanese encountered tremendous difficulties in administering and garrisoning the seized territories, and tried to solve its occupation problems by implementing a strategy of creating friendly puppet governments favorable to Japanese interests in the territories conquered, most prominently the Nanjing Nationalist Government headed by former KMT premier Wang Jingwei.However, atrocities committed by the Imperial Japanese Army, as well as Japanese refusal to delegate any real power, left the puppets very unpopular and largely ineffective.The only success the Japanese had was to recruit a large Collaborationist Chinese Army to maintain public security in the occupied areas.