Nasu Onsen-kyo

A deer, a hunter, and 630 CE

By the shrine record of Onsen Jinja in Nasu Yumoto, the springs were found in 630 CE by the hunter Kanō Saburō Yukihiro, who tracked a wounded white deer up the southern flank of Mt. Nasu and found it healing in a sulfur pool. The bath that grew around that pool is Shika-no-yu (鹿の湯, "deer bath"), and it has been in continuous public use ever since, which places it among the oldest working bathhouses in Japan. The current wooden building dates from 1941, but the bathing protocol, short immersions in undiluted source water graduated by temperature, is the older inheritance. Minamoto no Yoritomo is recorded as having bathed here in 1193; Matsuo Bashō passed through in 1689 on the road that became Oku no Hosomichi. By the late Edo period the informal national hot-spring ranking placed Nasu second in the east, behind only Kusatsu. The Nasu Imperial Villa, in use by the imperial family since 1926, sits a short distance below Yumoto on the same plateau.

Eight villages on the volcano's skirt

Nasu Onsen-kyo is not one town but a string of eight separate hamlets strung along the southern slopes of Mt. Chausu, each with its own source and its own water. Yumoto at the head of the valley is the acid-sulfur capital, the white-clouded water that smells of struck matches and stings briefly on broken skin. Ōmaru, Hachiman, and Bentén further down are simple thermal waters, gentler and clearer. Kita Onsen, reached on foot down a steep forest track, mixes simple, weak-salt, and iron springs in one nineteenth-century wooden inn. Takao carries sulfate and hydrogen sulfide; Asahi and Sandogo-ya round out the chain, the last requiring a hike past the ropeway's upper station. The eight share a postal code and almost nothing else, which is the point.

The plateau above the baths

The whole area sits inside Nikko National Park on Nasu-kōgen, a broad volcanic plateau that has been a summer-house district for Tokyo since the Meiji era. Mt. Chausu is still an active volcano with fumarole vents visible from its summit trail, a short climb from the ropeway. Below the treeline the plateau is dairy country: cheese workshops, ice-cream stands, horse-riding stables and a thick layer of resort hotels and golf courses spread along the access roads from Kuroiso. The contrast, ancient sulfur bath at the top, weekend cheese platter halfway down, is most of what makes Nasu work as a destination.