What was the name of the document that formally recorded Japan’s surrender in September 1945?

The document that formally recorded Japan’s surrender was the Japanese Instrument of Surrender.

It was signed on September 2, 1945, aboard USS Missouri in Tokyo Bay. The instrument stated that Japan accepted the provisions of the Potsdam Declaration and ordered Japanese forces to cease hostilities and surrender to designated Allied commanders.

The instrument was not the same as the Potsdam Declaration. The declaration, issued on July 26, 1945, was an Allied ultimatum setting out surrender terms. The instrument was the later document through which Japan formally accepted those terms and carried out the surrender.

Representatives of Japan signed first, followed by Allied representatives. The signatories represented the United States, China, the United Kingdom, the Soviet Union, Australia, Canada, France, the Netherlands, and New Zealand. The document marked the formal end of the Pacific War.