Japanese–Soviet Non-aggression Pact

The Soviet–Japanese Neutrality Pact (日ソ中立条約^?, Nisso Chūritsu Jōyaku), also known as the Japanese–Soviet Non-aggression Pact (日ソ不可侵条約^?, Nisso Fukashin Jōyaku), was a pact between the Soviet Union and the Empire of Japan signed on April 13, 1941, two years after the brief Soviet–Japanese Border War (1939). The pact was signed to ensure the neutrality between the Soviet Union and the Empire of Japan during World War II, in which both countries participated.

After the Fall of France and the subsequent expansion of the Axis Powers, the Soviet Union wished to mend its diplomatic relations in the Far East in order to safeguard its eastern border and concentrate on the European theatre of war. On the other hand, Japan, bogged down in a seemingly interminable war with China and with diplomatic relations with the United States rapidly deteriorating, sought an accommodation with the Soviet Union that would improve its international standing and secure the northern frontier of Manchukuo against possible Soviet invasion.

Stalin was initially unaware of Hitler's briefing to his generals that an attack on the Soviet Union by the European Axis Powers would enable Japan to challenge the United States overtly. This briefing was based on the belief that if such an attack occurred, the Soviet Union would be too preoccupied with fighting Germany, thus making Japan feel less threatened by any possible Soviet invasion of Manchukuo, allowing Japan to have enough provisions and capabilities to start a war with the United States. This treaty Stalin made would allow neither Japan nor the Soviet Union to have to fight in multiple fronts. Stalin believed that his "problems can be solved in a natural way if the Soviets and the Japanese cooperate". After concluding the nonaggression treaty, Stalin, in an unprecedented gesture, saw Foreign Minister Yosuke Matsuoka off at the train station. This was symbolic of the importance Stalin attached to the treaty; it also provided him with the occasion – in the presence of the entire diplomatic corps – to invite negotiations with Germany while flaunting his increased bargaining power.

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