This report identifies a different area of conflict from the Changkufeng incident of the previous year. The new area of dispute will lead to the summer battle of Khalkin Gol, also known as the Battle of Nomonhan.
As others have posted, the pasting delivered to the Japanese by Georgi Zhukov had some effect on diverting the Japanese from the “Northern Resource Area” (Siberia) and gave them more incentive to secure the “Southern Resource Area” (the NEI & Malaya). The motives to pursue the southern strategy were as much economic as military. The resources in Siberia were largely undeveloped, and with the technology and infrastructure of the time, the Japanese could not have expected a return on investment for several years. Years they didn’t have. Instead, the southern strategy, with already developed resources, offered an instant return.
The southern operation, as it turned out, required a huge logistical effort by Japan, mostly in the area of their slender merchant marine resources. Obviously the entire Imperial Japanese Navy is committed to this operation. However, the army’s commitment was rather small. Three divisions for Malaya, three division equivalents for the Philippines, a few brigades for the NEI. The bulk of the Japanese Army remained in the Home Islands, Manchuria or China.
Thanks to Soviet spy Richard Sorge, Stalin was made aware that the Japanese would not pursue the “northern strategy.” In October 1941 he was able to begin moving the bulk of the Far Eastern Army to save Moscow and lead the counter-offensive against the Germans. The Siberian frontier was pretty much left to border guards and light screening forces.
An interesting dual scenario:
1. Scenario 1: The Japanese change their minds and decide to take on the USSR as well as the USA in December. This is after Stalin has transferred the forces to Moscow. The Japanese can probably cut the Trans-Siberian railroad as far as Irkutsk, and a valuable lifeline of lend-lease through Vladivostok is cut off.
2. Scenario 2: Sorge gives Stalin the heads up that the Japanese are planning the invasion of Siberia. Stalin is now in a quandry. Does he move the Far East army to Moscow anyway, knowing he will give up Eastern Siberia? Does he leave the forces in place and lose Moscow or not mount a winter counter-offensive? Or does he move only part of the army and try to accomplish both objectives with limited resources on both fronts?
I was going to point out the fact of the resources in Siberia being undeveloped too. That was a factor in the Japanese decision to expand south rather than take on the Russians. There were a whole list of reasons that led to the decision that the Japanese made and everyone here has hit on one or more aspect. It really was a combination of everything that made Japan’s ultimate tact inevitable since the other option which was abandoning their military imperialistic policy (and gain thereof) was an impossible direction for those who were in power.
I am currently grinding my way through "At Dawn We Slept," by Gordon Prange, to get my Pearl Harbor timeline tuned up. It describes the great controversy within the Japanese military about the wisdom of Yamamoto's plan to take out the U.S. Navy at the beginning of hostilities. The Imperial Navy was evenly split, if not slightly negative, on whether the Pearl Harbor raid was a good idea. Those charged with the southern movement knew it was such a large scale operation they would need every available plane, both land-based and carrier-based to pull it off. They thought it unlikely that the fleet could get to Hawaii undetected and, once there, that they could do the damage necessary to make it worthwhile. Another "what if" scenario is - the Japanese concentrate all forces on the southern strategy and let the U.S. decide to venture east for the "All Out Battle," which was the Japanese doctrine throughout the war.