Excerpts from Books and Wikipedia
"Early on the morning of July 8, 1937, an ominous unplanned incident occurred some twenty miles south of Peking, when Japanese army units barracked at Fengtai clashed with Chinese garrison forces at the Marco Polo Bridge . . . The broad Japanese offensive followed strictly orders sanctioned by the emperor and issued from Tokyo, and after only two days of fighting led to the occupation of Peking and Tientsin, in both of which cities the British and French maintained small treaty-port settlements. . . . This second series of moves, by Chiang Kai-shek on one side and the Imperial navy on the other, turned the 'North China Incident' into the China war. . . . Concomitantly twenty naval planes based in Nagasaki made a four-hour transoceanic flight to bomb, for the first time, the Chinese capital of Nanking. . . . Dependent on imports of American oil, iron and steel, cotton, and copper, Japan's leaders feared that if it became a formal belligerent, the United States would deny it these strategic materials." It would last eight years, setting the stage for Communism in China and Japanese involvement in World War II. [Hirohito, p. 317-50]