After the castle was transferred from the Imperial Household Department to the City of Kyoto, on October 28, 1939 a total of 24 buildings including the aforementioned 6 buildings of Ninomaru Goten were designated National Treasures (former National Treasures) according to the Law for the Preservation of National Treasures, and 4 more were added in 1944.
城が宮内省から京都市に移管された後の昭和14年（1939年）10月28日に上記二の丸御殿の6棟とあわせて全24棟が国宝保存法に基づく「国宝」（旧国宝）に指定され、昭和19年（1944年）に4棟が追加指定された。