The Soviet/Japanese border war is mostly unknown to many, and this would include it's deciding battle, known as the Nomonhan Incident or the Battle of Khalkin Gol. I believe that this battle (waged spring/summer 1939), part of an undeclared Japanse/Soviet border war (Manchuria was then a Japanese puppet state known as Manchukuo) may well have been the battle that essentially decided the course of World War II. With the military in control of Japan's government, expansion of the Japanse Empire was one thing that both Army and Navy agreed on.
The Imperial Japanese Army, recalling success of the 1904-5 conflict with then Imperial Russia, favored a strike north to grab resource rich parts of the eastern Soviet Union all the way up to Lake Baikal whilst the Navy favored a strike south to grab everything between Japan and Australia.
After a long stalemate, Soviet commander Zhukov inflicted a decisive defeat upon the Japanese. The final destruction of the Japanese forces involved in this battle happened on 31st of august 1939 (an important date considering what would begin in Poland a day later). There were some Soviet mopping up operations in september but by then the Japanese decision to disengage from the Soviet/Japanese border conflict had already been made.
It was this experience, this humiliating defeat more than anything else that decisively swayed Imperial Japan's war planners to strike south rather than north. In order to get a free hand in the Pacific for their southward expansion, admiral Yamamoto knew that the US Pacific Fleet had to be neutralized, and though he did not favor war with the USA (he predicted that he might raise hell for 6 months to a year, but could give no guarantees thereafter) he was eventually to become the mastermind of the Imperial Navy's attack on the US Pacific Fleet at Pearl Harbor. Unfortunately for Japan, US carriers were not present when the Japanese struck.
The Nomonhan battle (spring/summer 1939) had more consequences than persuading the Japanese to strike south, rather than north. Stalin knew from intelligence that the Japanese were now looking south and could thus afford to send significant numbers of troops westward. The German High Command, which in 1941 would estimate that the Soviets might have up to 220 divisions, were surprised to learn that in the first 5 weeks of Operation Barbarossa (the German attack upon the Soviet Union) German troops had already identified 600 different Soviet divisions. The Germans quickly destroyed more than a 150 Soviet divisions and assumed that the battle was all but won, causing Hitler to order production to focus on submarines, rather than tanks. A fatal mistake, it later turned out to be. Hitlers Japanese allies had never told him about their experience with the Soviets in 1939. When Hitler declared war upon the United States 4 days after Pearl Harbor, he assumed Japan would declare war upon the Soviet Union, and was surprised they did not. Around that same time in december 1941, it was precisely those Siberian divisions involved in the 1939 Japanese/Soviet border war that would prove to be the key in the succesful Soviet attempt to drive the Germans away from Moscow, which they would never again reach.
So, summarized, the battle had 3 consequences. It caused Japan to look south, rather than north, meaning that the Japanese Navy had to attempt to neutralize the US Pacific Fleet to achieve control of the Pacific. It gave Siberian divisions key battle experience and it gave Stalin the opportunity to concentrate more of his forces westward than the Germans could possibly have imagined.
There was a series the History channel ran a few years ago about the Axis powers and they focused quite a bit on those battles.
Cool! I never heard of this part of the lead up to WWII. One other factor you didn't mention was the participation of Zukhov and the experience it gave him. He certainly showed later that his victory against the Japanese was no fluke. Thanks for posting this.
600 divisions!? Wow.
At Nomonhan the japanese learned the hard way that infantry with 'fighting spirit' are no match for a armored division or two. Especially on an open plain.
Zhukov gave the Japs a very bloody nose there.
The Nazis thought they had it made in winter of 1941 when they got within sight of Moscow, only to be struck and stopped dead by Zhukov's battle hardened troops from the east. It was all down hill for the Nazis after that, just one long terrible road to defeat.
over 25,000 casualties!
Just WOW!