by William Miniscalco
I have found an excellent source on Japanese thinking prior to the Pacific War, "The Japanese Decision to Move South (1939-1941)," by Sumio Hatano and Sadao Asada. It is a concise article and that will be extremely valuable for anyone serious about this subject, and contains many references for those who are really serious (unfortunately many of them are only available in Japanese). This is a chapter in a very good book, Paths to War: New Essays on the Origins of the Second World War, edited by Robert Boyce and Esmonde M. Robertson, St. Martin's Press (1989), ISBN 0-312-03012-6. [Now out of print, but Boyce has a newer book, The Origins of World War Two: The Debate Continues.] All other articles concern Germany. For those who cannot readily obtain this work, I will attempt to provide a brief synopsis.
First some relevant observations:
1. The war between Japan and the US, Britain, British Commonwealth countries, and the Netherlands was a consequence of Japans "advance to the south".
2. As with most wars, the origins of this one (as well as many errors in its prosecution) are permeated with miscalculations about how determined the adversary is.
3. Japanese national policy in this period was dominated by the military. If the Army and the Navy agreed on the approach to a particular issue (which seldom happened), the government was almost certain to go along.
4. Middle rank officers in both branches were much more aggressive in their plans and more determined to go to war than their superiors. Eventually this belligerent attitude percolated upward.
Up to the mid-1930s the Japanese policy was that of the Army: Northern advance, southern defense. This was a long-standing strategy dating back to incursions in Korea in the 19th century. In the mid-1930s the Navy advanced a competing "southern advance, northern defense" policy for two reasons: it wanted to justify obtaining a larger share of the defense budget and it recognized the importance of the strategic materials, particularly oil, in that region. It called for a peaceful expansion, however. In 1936 this policy was put on an equal footing with the Army policy, but this equilibrium was upset in 1937 when the Sino-Japanese War broke out and shifted the balance of power back to the Army. With the outbreak of the European war, Japanese policy (supported by both the Army and the Navy) was one of non-involvement because of the German-Soviet non-aggression pact of August 1939 and their rough handling by the Soviets in the Nomonhan incident of the same year. The middle rank officers, however, campaigned for using this distraction of European powers as an opportunity for expansion.
In the first half of 1940 two things happened that had a profound effect: the Army concluded that it could not win militarily in China using its current approach, and Germany's successes in Europe convinced the Japanese that Britain would soon be defeated and they needed to take action soon or "miss the bus." Consequently, the Army switched to a southern strategy that became national policy in July 1940 with some modifications made by the Navy. It called for settling the China conflict first and then moving into Indochina, although it left open the option of moving south even before things were settled in China on the grounds that this would block supplies to the Nationalist forces. It was based on the unrealistic hopes that a diplomatic settlement was possible in China (serious negotiations called the Kiri Project were underway with Chiang Kai-shek in the summer of 1940), and that war with Britain was possible without intervention by the US. The Navy objected to the latter assumption.
In September 1940, Japanese troops began marching into northern Indochina as part of the southern advance and the tripartite pact between Japan, Germany, and Italy was signed. In response, the negotiations with Chiang Kai-shek collapsed and the US and Britain imposed the first round of economic sanctions. Senior Japanese naval officers were convinced that even if Germany defeated Britain, a southern advance would ultimately lead to war with the US. By March 1941 the hard line being taken by the US regarding Japanese expansion caused the Army to come around to the Navy view, and plans were being drawn up that assumed that a war with the US was almost unavoidable.
Germany's invasion of the Soviet Union in June 1941 greatly reduced the threat in the north, thereby giving Japan more flexibility in the south. In July Japanese troops marched into southern Indochina, and in retaliation the US and Britain froze Japanese assets and imposed a complete embargo. The oil supply problem resulting from the embargo was so severe (a supply of 800 million liters per year vs. 5,400 required), that a quick resolution by military or diplomatic means was essential. The Army calculated that on the basis of oil supply alone, resources were insufficient to simultaneously pursue conflicts in the south and the north. So plans for a war with the Soviet Union were shelved. The foreign ministry was assiduously pursuing a negotiated settlement with the US right up to October 1941, and was willing to make significant concession in China. Roosevelt, however, believed that the best way to avoid or defer the war was to take a hard line. Consequently, the initiative failed (to the relief of the Army) and in mid-October the Konoe cabinet resigned and General Tojo became Prime Minister while retaining his position as Army Minister. Subsequent events are known to all.
I found the position Japan found itself in to be wonderfully summed up by the circular scenario developed by the operations section of the Japanese naval general staff in August 1940. To prepare for hostilities with Britain and the US, Japan would need to occupy Indochina for the raw materials. But this would cause the US to impose an embargo, which would in turn force Japan to seize the Dutch East Indies for oil. The latter would cause the US to go to war. Not exactly the order of events, but close enough. Unfortunately for Japan but predictable by those with more economic and political realism, the events would proceed far too quickly for it to make use of the resources and adequately prepare for war [my observation].
Another interesting observation the authors made was that although the Navy knew it was not prepared to take on the US and could possibly have prevented or delayed the war, it did not attempt to do so. The reason given is that for years the Navy had been demanding an increasing share of the defense budget to prepare for this war, and it would have lost face and influence to the Army if it admitted at this point that it was not up to the task.