Inō Tadataka (Inō Chūkei) (1745-1818) was born in Kazusa Province in 1745. He was adopted as the heir of the Inō family in the city of Sawara. He managed the family brewery until he was fifty. After he retired he began to study astronomy, geography and mathematics and began drawing maps. Between 1800 and 1816 he spent 3,736 days taking measurements and mapping Japan. His maps are accurate to about a thousandth of a degree. 
     Tadataka’s maps were not completed during his lifetime. In 1821 the Dai Nihon enkai yochi zenzu, an atlas of Japan based on his surveys was completed. The atlas contained 214 sheets on a scale of 1:36,000, 8 sheets on a scale of 1:216,000 and 3 sheets on a scale of 1:432,000. 
     Though Inō's maps were not in use during the Edo period, they were made the standard maps of the country in the Meiji era. Maps published by the British Navy in the 1860’s were based on Inō’s maps, and maps based on Inō’s were used as late as 1924 by the Japanese military.

     The stamp was issued in November 1995 to observe the 250th anniversary of the birth of Ino Tadataka. The map depicted on the stamp is a portion of a map attributed to Tadataka. The map shows an area centered, more or less on Edo (now Tokyo), and shows the province of Kazuza where Takataka was born. The city of Sawara is slightly north and just west of the the point on the right of the land in the map. The portrait of Tadataka is from a contemporary painting.