The Institute possesses about 35,000 pieces of historical documents and manuscripts including the following three groups.

(1) The Documents of the Nakajima family named Zeniya (1630~1904) are valuable records of a draper in Kyoto.

(2) The Documents of Inoguchiya, an express messenger agent (1723~1843) are the rare records of the modern history of communication. This group of documents was transcribed and published : Tadashi Watanabe and Mitsutoshi Tokunaga (eds.), Inoguchiya Hikyakutoiya Kiroku ( The Documents of Inoguchiya, An Express Messenger Agent), 4 volumes, 2001~2004.

(3) The Financial and Monetary Documents of the Ministry of Finance. The forme for publishing these documents was burnt down by the great Tokyo air raid in 1945 and it is regrettable that the publication of these documents is not realized at present.