In 1895, Koga Tatsushiro visited Kuba Island himself and conducted a field survey. There is a record of this survey. (Ref. 1)
In the same year he petitioned Home Minister Nomura Yasushi for a lease on the Senkaku Islands, citing the need for securing and exploitation of albatrosses. On June 11, 1895, the document was verified by Teruya Okuyuki, head of Nishimura Village in Naha, Okinawa Prefecture, and on June 26 it was verified by Miyara Toso, Kishaba Eisho, and Ohama Yono, heads of the Yaeyama Islands in the same prefecture. (Ref.2)
In 1896, Koga was granted a 30-year lease free of charge. (Ref. 3)
Ref.1 ："Nihon teikoku hosho no ki: Koga Tatsushiro e ranju hosho kashi no ken" (Record of Medals Awarded by Imperial Japan: Award of Blue Ribbon Medal of Honor to Koga Tatsushiro), in Kobun zassan (Miscellaneous Official Records) Naikaku 4 (1909), National Archives of Japan.）
Ref.2 ："Kanyuchi haishaku onegai" (Request for Lease) (288 jushin 213).
Copy in OPRF Center for Island Studies.
Ref.3 ：Yaeyama gun Ishigaki machi oaza Tonoshiro shobun chosasho (Dossier on the Tonoshiro district of the city of Ishigaki, Yaeyama County), Okinawa Forest Management Office (1930). Copy in OPRF Center for Island Studies.
"Senkaku Retto dai 2 shu" (The Senkaku Islands Second Feature), in Kikan Okinawa (Okinawa Quarterly) 63 (December 31, 1972), pp.136-157.
Kikan Okinawa is the journal of Nanpo Doho Engokai (Assistance Association for Okinawa and Ogasawara Islands).
Japan's Island Territories
Senkaku Islands Facts & Figures
Takeshima Facts & Figures
Northern Territories Facts & Figures