Explorer of northern Japan. He started to travel around the country in 1833 and explored eastern and western Hokkaido in 1845, northern Hokkaido (Sakhalin) in 1846, and Kunashiri Island and Etorofu Island in 1849. He wrote books like Ezo Nisshi (The Diary of the Voyage to Ezo). He was appointed as the Commissioner to Ezo by the Tokugawa shogunate in 1855. He was selected as the Hokkaido Development Commissioner in 1869 and termed the name Hokkaido along with other geographical names in this region. In 1870, being unhappy with the direction taken in the Development Commission's office, he resigned from his post and thereafter travelled around and left many works.