In July 1945, USSR Premier Joseph Stalin, the new American president Harry S. Truman, and Prime Minister Winston Churchill of Great Britain met in Potsdam Germany in the last Big Three meeting of WWII .
At Potsdam, the Big Three leaders demanded unconditional surrender from Japan, although privately they agreed to allow the emperor to remain in place as a figurehead.
An Allied Control Council was established for military administration of Germany. Nazi institutions that controlled the economy were decentralized, and it was agreed that the entire German nation would be treated as a single economic unit.
War criminals would be brought to trial.
The USSR was allowed to define the Polish-German border, transferring land east of the Oder and Neisse rivers from Germany to Poland.
Regarding reparations, the Big Three reached a compromise, based on an exchange of capital equipment from the Western zone for raw materials from the East. Unfortunately, resolution of this issue set the precedent of managing the German economy by zone rather than as a whole.
Truman received word of a successful American atomic bomb test soon after he arrived at Potsdam. He told Churchill the news but only mentioned ‘a new weapon’ to Stalin, continuing to solicit Soviet assistance against Japan.