Titsingh, p. 412; n.b., the first copy of this rare book was brought from Japan to Europe by Isaac Titsingh in 1796. Titsingh translated the text from Japanese and Chinese; and his work was then supplemented for posthumous publication by Julius Klaproth. The initial Japanese authorship is confirmed; the precise nengō-dating is confirmed in the same passage -- see Titsingh, p. 406.