On July 26, 1945, United States President Harry S. Truman, United Kingdom Prime Minister Winston Churchill, and President of China Chiang Kai-shek issued the document, which outlined the terms of surrender for the Empire of Japan, as agreed upon at the Potsdam Conference. The ultimatum stated that, if Japan did not surrender, it would face "prompt and utter destruction."[1][2]
https://en.wikipedia.org/wiki/Potsdam_Declaration?
https://imtfe.law.virginia.edu/collections/tavenner/4/3/interpretation-potsdam-declaration
