When the 30-year free lease of Uotsuri Island and Kuba Island expired in August 1926, having originally been granted in August 1896, the Japanese government changed the terms from a free lease to a paid lease. Koga Tatsushiro's successor, Koga Zenji, made annual lease payments of 26 yen 40 sen for Kuba Island for four years and eight months from September 1926 until March 1931, and total annual payments of 136 yen 61 sen for both Uotsuri Island and Kuba Island from April 1931. (Ref. 1)
Ref.1 ：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.
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