What was the Allied ultimatum calling for Japan's unconditional surrender called?

The Allied ultimatum calling for Japan's unconditional surrender was called the Potsdam Declaration.

The declaration was issued on July 26, 1945, during the Potsdam Conference in Germany. The United States, the United Kingdom, and China warned Japan to surrender or face “prompt and utter destruction.”

Its terms addressed Japan's disarmament, the removal of militarist influence, occupation by Allied forces, and the establishment of conditions for a peaceful government. It also stated that Japanese sovereignty would be limited to the main islands and other islands designated by the Allies.

The Soviet Union did not initially sign the declaration because it was still neutral in its war with Japan. The declaration became the principal framework Japan accepted when it announced surrender in August.