On July 7, 1937 a handful of Chinese and Japanese soldiers exchanged rifle-fire in the vicinity of the Marco Polo Bridge about thirty miles from Peking. This, minor fracas precipitated a sequence of events that soon propelled Japan into full-scale hostilities on the mainland—a war that was significantly to influence the course of Japanese-American negotiation in the fateful months leading up to the Pacific War. Many historians have portrayed the China incident as the consequence of a conspiracy by the Japanese military and as a repetition of a pattern of aggression identical with that of the Mukden Incident of 1931. With this approach, the Sino-Japanese war presents little apparent difficulty to our ascertaining why the fighting at the Marco-Polo Bridge occasioned a major war. The culprit is the Japanese military.