Former Imperial Household Ministry (Imperial Household Agency)

The former Imperial Household Ministry (宮内省, Kunaishō) building stands within the grounds of the Tokyo Imperial Palace in Chiyoda Ward. Originally constructed to house the ministry responsible for all matters relating to the Imperial household, the building played a pivotal role in the final hours of the Pacific War and remains in active use today as the headquarters of the Imperial Household Agency (宮内庁, Kunai-chō).

During the war years, the Imperial Household Ministry administered the vast affairs of the Emperor and the Imperial family, managing court ceremonies, imperial properties, and the daily operations of the palace. The ministry's wartime staff numbered over 6,200 personnel. As Japan's military situation deteriorated in 1945, the palace grounds — including an underground bunker (御文庫附属室, Obunko Fuzokushitsu) constructed in 1942 beneath the Fukiage Imperial Gardens — became the site of critical war-ending deliberations, including the Supreme War Direction Conference of August 10 and the Imperial Conference of August 14, 1945, where Emperor Showa made his final "sacred decision" (聖断) to accept the Potsdam Declaration.

On the night of August 14, 1945, Emperor Showa proceeded to the Imperial Household Ministry building to record the Imperial Rescript on the Termination of the War. In a room fitted with recording equipment by NHK engineers, the Emperor read the rescript twice, producing two sets of phonograph discs — the Gyokuon-ban (玉音盤). These discs were entrusted to Chamberlain Tokugawa Yoshihiro, who hid them in a small safe in the office of the Empress's household staff (皇后宮職事務官室), concealed among other documents.

In the early hours of August 15, officers led by Major Kenji Hatanaka launched the Kyūjō Incident (宮城事件), a desperate coup d'état to prevent the surrender broadcast. After murdering Lieutenant General Takeshi Mori, commander of the 1st Imperial Guards Division, the rebels forged orders to mobilize palace guard troops and systematically searched the vast palace complex for the recording discs. They ransacked offices within the Imperial Household Ministry building and interrogated officials, but the recordings remained safely hidden. The coup collapsed by dawn, and at noon on August 15, the Gyokuon-hōsō was broadcast nationwide, marking the effective end of the war.

Following Japan's defeat, sweeping reforms reorganized the ministry. In 1947, the Imperial Household Ministry was downgraded to the Imperial Household Office (宮内府) under the Prime Minister, and its staff was drastically reduced from over 6,200 to approximately 1,500. In 1949, it was further reorganized as the Imperial Household Agency (宮内庁). The original building continues to serve as the Agency's main office, making it one of the few wartime government structures in Tokyo still fulfilling its original administrative function on its original site.