The author was able to find a manuscript of Hoshu Katsuragawa’s “Hon’yaku-Chikyu-Zenzu-Ryakusetsu,” which has not been found in published book form until present day.

The manuscript features maps, the date when it was copied, and the name of the transcriber whose existence could be verified. It also turned out that he left several other map works, all of which are detailed and faithful to their originals.

The manuscript also includes previously unknown 18 additional maps from “Hon’yaku-Chikyu-Zenzu-Ryakusetsu.”

On the basis of these new finding, the author has attempted to search for the original of Hoshu Katsuragawa’s “Hon’yaku-Chikyu-Zenzu-Ryakusetsu.”

The author has concluded that the original could be inferred to be a Dutch version of a school geography textbook, which included maps reflecting the administrative divisions from 1758 to 1772.

It was found that “Geographische oefening,” 1758-1778 fits the description.

By comparing with the original, it could be observed that Hoshu Katsuragawa intended the world geography for enlightenment rather education, and that the maps were partially edited.

As for the reason why “Hon’yaku-ChikyuZenzu-Ryakusetsu” has not been found in published book form, it could be assumed that Hoshu Katsuragawa gave up on publishing “Hon’yakuChikyu-Zenzu-Ryakusetsu” when Masatsuna Kutsuki, a fellow Dutch scholar, published “Taisei-Yochi-Zusetsu,” a geography book with a similar purpose, in 1789.

Because “Hon’yaku-Chikyu-Zenzu-Ryakusetsu” was unpublished, it was not known among fellow Dutch scholars.

P. J. Prinsen’s “Geographische oefeningen” (“Chigaku-Seisou”), the successor to the original, was completely translated by Gentan Sugita 65 years later in 1856.

It can be said that the whole picture of “Hon’yakuChikyu-Zenzu-Ryakusetsu” has finally become clear 230 year after its completion by Hoshu Katsuragawa.

The Sanko Library owns the manuscript maps named “Inoh Tadataka Jissoku-Genzu”，which were drawn for the first surveyed map of Japan by Inoh Tadataka (1745-1818). “Inoh Tadataka Jissoku-Genzu” is based on 30 sheets of the “Shitazu”, the manuscript maps. The scales of “Inoh Tadataka Jissoku-Genzu” are classified into medium (1:216000) and small (1:432000), which correspond to the scales of Inoh’s Map of Japan. On the “Inoh Tadataka Jissoku-Genzu” the results of Inoh’s survey are plotted by needle points.

The General Library of the University of Tokyo owns the manuscript maps named “Sokuchi-Genzu”. Those are same type maps as the Sanko Library owns. The “Sokuchi-Genzu” and “Inoh Tadataka Jissoku-Genzu” are very important materials for the research of Inoh’s Map.