Former Ministry of Foreign Affairs Building

The Ministry of Foreign Affairs of Japan (外務省, Gaimushō) has occupied the Kasumigaseki district of Chiyoda Ward, Tokyo since 1871, when it became the first government ministry to establish itself in the area. The original building, a grand Western-style structure designed by French architect Boinville, was completed in 1881 (Meiji 14) but burned down in 1877 and was rebuilt. This second iteration was destroyed during the Great Kanto Earthquake of September 1, 1923.

The ministry was rebuilt in reinforced concrete as part of the Kasumigaseki government district reconstruction program during the early Showa period. This building served as the center of Japanese diplomatic operations throughout the Pacific War era (1941–1945).

In July 1945, when the Allied Powers issued the Potsdam Declaration from the Potsdam Conference (July 26, 1945), the Foreign Ministry was among the first government agencies to receive the broadcast via monitoring stations. Ministry officials, including the Treaty Bureau and senior diplomats, undertook the critical task of translating the declaration into Japanese and analyzing its legal implications. The deliberations over whether to accept, reject, or "mokusatsu" (ignore) the declaration—a decision with world-altering consequences—were conducted in part within these walls, with Foreign Minister Shigenori Tōgō advocating for acceptance.

Following the Imperial decision to accept the Potsdam Declaration on August 14, 1945, the Foreign Ministry became the center of surrender preparations. Officials worked to draft Japan's formal response and prepare the Instrument of Surrender documentation. The ministry coordinated with the Allied powers through neutral diplomatic channels (primarily Switzerland and Sweden) to arrange the mechanics of the formal surrender ceremony.

On the morning of September 2, 1945, Foreign Minister Mamoru Shigemitsu—appointed specifically for this solemn duty under the Higashikuni cabinet—departed from the Foreign Ministry compound. Together with ten other Japanese delegates, he traveled by car to Yokohama, boarded the destroyer USS Lansdowne, and was taken to the battleship USS Missouri anchored in Tokyo Bay. At 9:04 AM, Shigemitsu, walking with difficulty due to a prosthetic leg (the result of a 1932 bombing in Shanghai), signed the Instrument of Surrender on behalf of the Emperor and the Japanese Government, formally ending the Second World War.

The ministry building suffered catastrophic damage during the devastating air raids of May 25, 1945, when much of Kasumigaseki was firebombed. The main building was completely gutted by fire, and approximately 20,000 volumes of diplomatic documents were lost. Only a single four-story archive building survived, having been physically separated from the other structures. After the war, the ministry operated from temporary quarters until the current complex was constructed.

The present Ministry of Foreign Affairs complex was designed by architect Hideo Kosaka, selected through a national design competition. The North Building was completed in 1960 (Showa 35), followed by the Central and South Buildings in 1970 (Showa 45), and the New Building in 1996 (Heisei 8). The buildings feature a distinctly Japanese aesthetic with exposed structural columns and beams, deep eaves, and thin blue ceramic terracotta exterior walls. The complex underwent seismic base-isolation retrofitting between 2001 and 2004. The Diplomatic Archives (外交史料館), housed within the compound, preserves surviving wartime documents including the original Instrument of Surrender.