Abstract: Japanese invasion into China was carefully plotted for along time,but the Lugou Incident as a prelude to the aggression war was not an event planned beforehand by the Japanese government.Before the incident Japan tride,for its own interest,to adjust its policy to China and to relax the tension between the two countries.After the incident,two parties,one against and the other for the war,in the Japanese government quarreled for several days.As a consequence the Japanese governwent decided to sent troops to C...