The materials related to the land survey of northern Japan by Imai Hachikurô (1790 -1862), a retainer of the Matsumae clan, are comprised of 84 items including the maps of northern Japan that he created. Most of the materials are illustrations and maps that are comprised of 69 items. In addition, 9 items of documents and records as well as 6 tools for land surveys are included.
Imai Hachikurô was born in Matsumae in Kansei 2 (1790), as the son of a minor retainer of Matsumae and was named Nobukata. Following the transference of the fief of Matsumae to Tohoku due to the direct rule of the island Ezo (present-day Hokkaido) by the Shogunate Government of Edo during the Bunka era (1804-1818), the Imai family had to return his fief, but they served as the police constables of the magistrate's office of Matsumae. The technique of his land survey was based on the method by Inô Tadataka, which became the base of mapping northern Japan in later years, was one learned from Mamiya Rinzô who had also served at the same magistrate's office. In Bunsei 4 (1821), the fief of Ezo Island was returned to the Matsumae clan. Then they took Hachikurô into their service again and ordered him to survey the entire land of Ezo in Bunsei 11 (1828). His land survey of Ezo, including the islands of Okushiri, Rishiri, Rebun, North Ezo (Karafuto), Kunashiri, Shikotan, Etorofu and Habomai, took about ten years until Tenpô 9 (1838), followed by three years of drafting maps from Tempô 10 to 12 (1841). Thus the maps of Ezo Island and the other islands around it were completed. The clean copies of those maps made by Hachikurô were submitted to the Matsumae clan, but they were lost in the Hakodate War between Meiji 1 to 2 (1868-1869). Hachikurô continued to conduct land surveys after that as well and he died in Matsumae in Bunkyû 2 (1862) at the age of 73.
The illustrations and maps included in the materials related to the land survey of northern Japan by Imai Hachikurô that are owned by us now are those that were kept by the Imai family as duplicates of the clean copies, which were bought by this museum in Taishô 3 (1914). They are broadly categorized into "the original drawings of the land survey" based on his actual survey and "the drafts of the land survey" based on the original drawings. As examples, P-1105 "The Original Drawing of the Land Survey of Ezo" (18 maps in total) is combined with P-1116 "The Draft of the Land Survey of Ezo" (consisting of three parts) and also P-1127 "The Original Drawing of the Land Survey of Rishiri and Rebun Islands" is combined with P-1124 "The Draft of the Land Survey of the Rishiri and Rebun Islands". Among the maps of northern Japan made by Hachikurô, very detailed ones for the islands that neither Inô Tadataka nor Mamiya Rinzô had investigated are contained. A lot of local names in Ainu can be seen on those maps. In addition to the illustrations and maps, documents and records such as P-1143 "Record of Personal Experiences and Rumors in the Back Regions from Horokotan in North Ezo," which described the hearsay about the movement of the Russians in North Karafuto and P-1147 "Small Paper Pelorus," a tool used in land surveys, are preserved.
These materials are not only survey maps of northern Japan made by the retainer from Matsumae, but are also the last maps of northern Japan based on the land survey technique in the Inô style and thus they are designated as important cultural properties, because they are very valuable in terms of the mapping history of Japan.