 In spite of Soviet–Japanese Neutrality Pact, at the Yalta agreement in February 1945, the US, the UK, and the USSR had agreed that the USSR would enter the war on Japan within three months of the defeat of Germany in Europe.This Soviet–Japanese War led to the fall of Japan's Manchurian occupation, Soviet occupation of South Sakhalin island, and a real, imminent threat of Soviet invasion of the home islands of Japan.This was a significant factor for some internal parties in the Japanese decision to surrender to the US and gain some protection, rather than face simultaneous Soviet invasion as well as defeat by the US.