High Quality Content by WIKIPEDIA articles! The Soviet?Japanese Neutrality Pact, more extensively known as Japanese-Soviet Nonaggression Pact as well as German-Soviet Nonaggression Pact, was a pact between the Empire of Japan and the Soviet Union signed in 1941, two years after the brief Soviet-Japanese Border War (1939)In September 1939, with the outbreak of general war in Europe between Nazi Germany and Poland, the United Kingdom, and France, the Soviet Union needed to mend its diplomatic relations in the Far East in order to concentrate on the growing threat to European Russia in the west. 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.