The Russians and Japanese have never really gotten along. They have competed for similar territories for years. (Wieczynski, 1983) Before WWII they had a few border wars over the territories of Mongolia and Manchuria. ("Soviet-Japanese Neutrality Pact,") Their skirmishes went further in the past still, including the Russo-Japanese War which required the intervention of the President of the United States of America of that time, Theodore Roosevelt. The skirmishes between Japan and Russia are usually about the borders of the two powerful countries and the countries they controlled at the times and their tendency to be too close together for their comfort (Manchuria and Mongolia). (Wieczynski, 1983)
The Soviet-Japanese Neutrality Pact was orchestrated by the Soviet Union and Empire of Japan on April 13, 1941. ("Soviet-japanese neutrality pact," 2008) The signer from the Soviet Union was Foreign Minister Vyacheslav Mikhailovich Molotov for the Soviet Union. The signers for the Empire of Japan were Foreign Minister Yosuke Matsuoka and Ambassador Yoshitsugu Tatekawa. Alongside signing the Soviet-Japanese Neutrality Pact in Moscow they also signed an agreement on the same day to respect the borders of Manchukuo (a puppet state in Manchuria controlled by the Japanese) and the People's Republic of Mongolia. ("Declaration regarding Mongolia," 2008)
The reasons behind the treaty had to do with the chaotic times that the two powers were dealing with and the chaotic regions they were situated in. In 1938-1939 the Soviets and the Japanese had had two borders wars on the borders of Manchuria. (Wieczynski, 1983) The first border war was the Battle of Lake Khasan, which lasted July 29, 1938 to August 11, 1938. The second border war was the Battle of Khalkhin Gol in the 11th of May in 1939 to the 16th of September in 1939. ("Soviet-Japanese Neutrality Pact," )
These border wars, unsurprisingly, left the two powers uneasy towards each other. Japan and the Soviet Union also had to deal with the other conflicts going on at the time. Nazi Germany had invaded Poland in the 1st of September in 1939 to the 6th of October in 1939. War in Europe (and eventually, WWII) was breaking out in Europe. The United Kingdom and France were standing against Hitler. The Soviet Union had enough threats on western Russia to deal with at the time, let alone having to deal with Japan threatening them on the eastern border. (Wieczynski, 1983)
Japan too was dealing with conflicts of the time. They were uneasy with the Russians on their west and were also dealing with the Second Sino-Japanese War (they invaded China in July 7th 1937) which lasted throughout and till the end of WWII. Also, their political ties to the sleeping giant of the United States of America were being severed. They needed their western border to be secure from possible Soviet invasion. ("Soviet-Japanese Neutrality Pact," )
Because of these conflicts the Soviet Union and Empire of Japan agreed to a treaty to keep their respective eastern and western borders secure from each other. Their peace nonaggression pact technically lasted until April 13, 1946. However, it was not completely respected due to the massive conflict that was World War 2.
Japan had its chance to invade the Soviet Union later in 1941 after signing the Tripartite Pact with Germany and Italy. The Soviet Union predicted the worst would come and they would have to fight two fronts due to Hitler's invasion of the Soviet Union called Operation Barbarossa (began in 22 June 1941). The Soviets did their best not to infuriate the Japanese, treating their diplomats with the utmost respect and care despite the two countries being on opposite sides of WWII. (Stephan, 1994)
Luckily for the Soviets, the Japanese actually didn't have the manpower to deal with both the War in the Pacific and an invasion of the Soviets, especially when America entered the War against the Axis Powers and Soviet Russia proved to be a much harder battle than Hitler and his goons had counted on. The neutrality pact between Russia and Japan would remain in effect for some time to come. (Stephan, 1994)
On August 8, 1945 the pact would finally be broken. ("Soviet denunciation of the pact with japan," 2008) The Soviets, keeping a promise to the Allies that they had pledged at the Yalta Conference, invaded Manchuria. ("Soviet declaration of war on japan," 2008) Although the pact was technically still in effect for another year, they had basically broken it by declaring war on Japan roughly 2-3 months after Germany had surrendered. ("Soviet-Japanese Neutrality Pact," )
1. Soviet-Japanese Neutrality Pact. Wikipedia. Retrieved (2010, April 27) from http://en.wikipedia.org/wiki/Soviet%E2%80%93Japanese_Neutrality_Pact
("Soviet-Japanese Neutrality Pact," )
2. Soviet-japanese neutrality pact april 13, 1941. (2008). The Avalon Project, Retrieved from http://avalon.law.yale.edu/wwii/s1.asp
("Soviet-japanese neutrality pact," 2008)
3. Declaration regarding mongolia. (2008). The Avalon Project, Retrieved from http://avalon.law.yale.edu/wwii/s2.asp
("Declaration regarding Mongolia," 2008)
4. Soviet denunciation of the pact with japan. (2008). The Avalon Project, Retrieved from http://avalon.law.yale.edu/wwii/s3.asp
("Soviet denunciation of the pact with japan," 2008)
5. Soviet declaration of war on japan. (2008). The Avalon Project, Retrieved from http://avalon.law.yale.edu/wwii/s4.asp
("Soviet declaration of war on japan," 2008)
6. Stephan, J. J. (1994). The Russian far east: a history. Stanford: Stanford University Press.
7. Wieczynski, J. L. (1983). Soviet-Japanese Neutrality Pact. (1983). The Modern encyclopedia of russian and soviet history. Gulf Breeze, Florida: Academic International Press.