After the Fall of France and then the expansion of the Axis Powers, the Soviet Union wished to mend its diplomatic relations in the Far East to safeguard its eastern border and to concentrate on the European Theatre of World War II.

On the other hand, the Empire of Japan was bogged down in a seemingly-interminable war against China and had rapidly-deteriorating diplomatic relations with the United States.

That briefing was based on the belief that if such an attack occurred, the Soviet Union would be too preoccupied with fighting Nazi Germany.

After concluding the nonaggression treaty, Stalin, in an unprecedented gesture, saw Japanese Foreign Minister Yosuke Matsuoka off at the train station.

It also provided him with the occasion, in the presence of the entire diplomatic corps, to invite negotiations with Germany and to flaunt his increased bargaining power.

That had a direct bearing on the Battle of Moscow since the absence of a Japanese threat allowed the Soviets to move large forces from Siberia and to send them to the front against the Germans.

General Tomoyuki Yamashita, who was known for his achievements in the Battle of Singapore, was sent to Manchuria in July 1942 and tasked with organizing troops for the invasion.

[4] At the Yalta Conference in February 1945, Stalin secretly agreed to enter the war against Japan in exchange for American and British recognition of certain Soviet territorial claims in Asia.

[9] During the Soviet invasion, Japanese forces on the Asian mainland were unprepared to resist and were overrun relatively quickly.

In the last campaign of the war, Soviet territorial gains in Asia were Manchukuo, Mengjiang (Inner Mongolia) and northern Korea.

The Presidium of the Supreme Soviet of the Union of Soviet Socialist Republics and His Majesty the Emperor of Japan, guided by a desire to strengthen peaceful and friendly relations between the two countries, have decided to conclude a pact on neutrality, for which purpose they have appointed as their Representatives: who, after an exchange of their credentials, which were found in due and proper form, have agreed on the following: In confirmation whereof the above-named Representatives have signed the present Pact in two copies, drawn up in the Russian and Japanese languages, and affixed thereto their seals.