“Unzen is the collective name of the three hamlets of Furu-Unzen, Shin-yu, and Kojigoku, lying near the wonderful solfatra of Ojigoku in a hollow of the range called Unzen-take. Each hamlet stands about 10 min. from the other.
“… This remarkable spot, 2,550 ft. above the sea, noted for its sulphur springs, its varied and beautiful scenery, and its bracing air, has become a sanatorium, not only for Nagasaki and neighborhood, but for the residents of the China treaty port.
“From the Japanese point of view, a course of these upper springs is considered necessary to effect a complete recovery after the patient has passed through the routine of the mineral baths at Obama.”
– A Handbook for Travellers in Japan, Basil Hall Chamberlain & W.B. Mason, 1907