 Likewise, the superior numbers of the armies of the Soviet Union in Europe was a factor in the US decision to demonstrate the use of atomic weapons to the USSR, just as the Allied victory in Europe was evolving into division of Germany and Berlin, the division of Europe with the Iron Curtain and the subsequent Cold War.Having ignored (mokusatsu) the Potsdam Declaration, the Empire of Japan surrendered and ended World War II, after the atomic bombings of Hiroshima and Nagasaki and the declaration of war by the Soviet Union.In a national radio address on August 15, Emperor Hirohito announced the surrender to the Japanese people by "Gyokuon-hōsō".