What was the written agreement called that formally recorded Japan’s surrender in 1945?

The written agreement was called the Japanese Instrument of Surrender.

This document recorded Japan’s capitulation to the Allied powers and formally ended the state of war in the Pacific theater. It was signed on September 2, 1945, aboard the USS Missouri in Tokyo Bay. The document required Japan to accept the terms of the Potsdam Declaration and ordered Japanese forces to cease hostilities and surrender.

The Potsdam Declaration was different: issued on July 26, 1945, by the United States, the United Kingdom, and China, it demanded Japan’s surrender and warned of destruction if Japan refused. Japan’s later written instrument confirmed acceptance of those terms; the two documents are therefore closely related but not interchangeable.

The surrender instrument was signed by Japanese representatives, General Douglas MacArthur for the Allied powers, and representatives of the United States, China, Britain, the Soviet Union, Australia, Canada, France, the Netherlands, and New Zealand.