For Japan, World War II began with an effort to secure imperial interests in China. Even as Japan's escalating imperial ambitions on the Asian continent precipitated military conflicts with the Soviet Union, with the United States, and with the British Empire, China remained at the center of Japan's vision and experience of total war. The occupation, in 1931, of Northeast China and the transformation of what had been a Japanese sphere of influence into the puppet state of Manchukuo signaled a turning point in the methods and goals of Japanese imperialism. The challenge of Chinese nationalism placed Japan on the defensive, triggering a shift from diplomacy to militarism and helping forge a domestic consensus behind the need to defend the imperial “lifeline” in China at all costs - even at the risk of war with the Western imperialists in Asia. But what began as a small war in Manchuria in 1931 expanded into the titanic naval battles in the Pacific and ended in the hellfires of Hiroshima and Nagasaki. Throughout the fifteen years of warfare, each stage of escalation, each opening of a new war front was necessitated by the perceived need, on the Japanese part, to defend imperial interests in China. In other words, China remained the center of Japan's total war effort.