In 1939, Japan wavers between two schools of thought. The first, the Hokushin-ron, advocates a thrust to the north against the USSR, into Manchuria and Siberia. The second, the Nanshin-ron, targets the south and its resources: oil, tin, rubber from the Dutch East Indies, Malaya, and the Philippines.
The two paths do not require the same weapons. The north calls for tanks, artillery, and land-based aviation; the south demands a powerful navy, naval aviation, and amphibious capabilities. Industry cannot finance everything at once.
In the summer of 1939, the clash with the at Khalkhin Gol (Nomonhan) turns into a disaster for the Japanese troops. The General Staff must decide which axis to commit to for the long term.
Toward which strategic axis should Japan direct its military and industrial effort as a priority?
After the heavy defeat at Nomonhan (August-September 1939), which dispelled any illusion of an easy victory over the USSR, Japan shifted toward the Nanshin-ron, the southern strategy. The industrial effort was redirected toward the navy and naval aviation. This choice would lead to the conquest of the resources of Southeast Asia and, in December 1941, to the attack on Pearl Harbor, opening a fatal conflict with the United States.









