Brief overview of "Pre-War Public Finance":
There are two separate public sources for the Public Finance statistics published on this page.
Figures for "Public Debt Total", "Government Bonds", "Public Borrowings" are from Government Bonds Statistics Annual Report for each year, published by the Ministry of Finance. The ratio to GNP are our calculation. Details for Pre-War GNP are here. The Government Bonds Statistics Annual Report are unfortunately not published in English. You can find recent Annual Reports published here in the Ministry of Finance’s home page. Annual Reports from earlier year are not readily available online, but as an example, the Annual Report from 1915 can be found here, thanks to Google Books.
Figures for “Public Revenue”, “Public Expenditure” are from “Hundred Years of the Ministry of Finance”, Separate Volume, 1969, Published by Association of MoF Treasury (Okura Zaimu Kyokai). The ratio to GNP are our calculation. The book is again not published in English.