Nine Allied powers signed the Japanese Instrument of Surrender after Japan signed it in 1945.
The signatories represented the United States, China, the United Kingdom, the Soviet Union, Australia, Canada, France, the Netherlands, and New Zealand. Douglas MacArthur signed first for the Allied powers, followed by the national representatives.
The ceremony therefore included Japan's two principal signatories and representatives of nine Allied powers. The countries were arranged in a carefully managed order reflecting the coalition that had fought Japan across the Pacific and Asia.
The number can be confused with the total number of people who signed, because multiple Japanese delegates attended but only two signed the instrument. MacArthur also signed before the national representatives, in his capacity as Supreme Commander for the Allied Powers.