日ソ中立条約
From 1932 to 1945 the Empire of Japan and the Soviet Union had a series of conflicts. Japan had set its military sights on Soviet territory as a result of the "Hokushin-ron" doctrine, and the Japanese establishment of a puppet state in Manchuria brought the two countries into conflict. The war lasted on and off with the last battles of the 1930s (the Battle of Lake Khasan and the Battles of Khalkhin Gol) ending in a decisive victory for the Soviets. The conflicts stopped with the signing of the Soviet–Japanese Neutrality Pact on April 13, 1941. However, later, at the Yalta Conference, Stalin agreed to declare war on Japan; and on August 5, 1945, the Soviet Union voided their neutrality agreement with Japan.