The first map of the whole Japan based on actual surveys was created by “Inoh surveys”, Inoh Tadataka （1745-1818） mainly led, which had been conducted mostly as a government project from 1800 to 1816. During the surveys, various maps were made in each survey and some of those were submitted to the Edo Shogunate. At long last, 3 types of map （214 sheets of a large 1:36,000 scale map, 8 sheets of a medium 1:216,000 scale map, 3 sheets of a small 1:432,000 scale map） were completed, and submitted to the Edo Shogunate in 1821. However, it is said that the latest set submitted then was all destroyed by the fire of the Imperial Palace in 1873.
Those maps created by Inoh surveys and its manuscript copies are called “the Inoh maps” today, and a part of such maps remain at some museums, libraries in Japan and U.S.A.
At the University of Tokyo, 7 sheets of the Inoh map （“Todai maps” in this paper） whose scale is the medium 1:216,000 （called “Chu-zu”） are preserved, and considered the same kind of ones as the latest set in 1821. Though a complete set of the medium scale consists of 8 sheets, Todai maps include only 7 sheets except 1 sheet of Kanto district. 5 sheets of those are the original which are called “huku-hon”, but 2 sheets are considered manuscript copy. On the history of Todai maps, it is thought that the maps had been preserved in the faculty’s office of Science. But, little known about the history before that time and what the origin is.
On the other hand, Naritasan Library for Buddhism owns 8 sheets of the medium scale Inoh map （“Narita maps” in this paper）, that are the same latest ones as Todai maps. Narita maps are regarded as manuscript copy, and the cartography was well performed. These Inoh maps are not also clear on its history and origin.
While researching the history of Todai maps for several years, the author found out an interesting similarity between Todai maps and Narita maps. In a photograph of Narita map appeared in a magazine, a part of “Chubu” district accorded with Todai map in the position and the direction of the place name. In addition to the above, it is recognized that 5 sheets of Todai map are the original and Narita maps are copies. If we consider the fact mentioned above, “it is possible that Narita maps are the copy of Todai map”. If this hypothesis is true, the relation between both Inoh maps might be an important evidence to clear up both origins. Therefore, to verify the hypothesis is extremely important to make the histories of both maps clear.
In February, 2015, the author photographed replicas of Narita maps at Naritasan Library, and compared the photographs with Todai maps immediately. It was found from the comparison that 5 sheets of Narita map are the copy of Todai map. In this paper, the author will report the results of detailed analysis including comparisons with other Inoh maps owned by some organizations, and will also describe the histories of both Inoh maps, inferring the origins from the relation.