Naradanosato Onsen Jotei-no-yu

Jotei-no-yu is a municipally run day-use hot spring in Narada, a hamlet at the far end of Hayakawa in Yamanashi Prefecture and a long-standing staging point for climbers heading into the Southern Alps. It stands beside Lake Narada, a reservoir on the Hayakawa river, in what is officially the least populated town in Japan. The name Jotei-no-yu, the Bath of the Empress, comes from a local tradition that Empress Koken, the 46th sovereign, took the waters here during the Tenpyo era. She is said to have first visited Nishiyama Onsen to treat an illness, then pressed further up the valley in search of a more potent spring and stayed in Narada for eight years. Seeing seven terraces descending from her dwelling to the river, she reportedly remarked that the capital at Nara had seven avenues and this place had seven terraces, so it too was truly Nara, which is how the name Narada is said to have arisen. Villagers called her the King of Nara.

The water is a sodium chloride and bicarbonate spring, classified as hypotonic and alkaline. It emerges at 41.3C with a pH of 8.8 and a total mineral content of 1.714 grams per kilogram, clear and colourless but carrying a faint sulphurous smell and taste. It is served exactly as it comes from the ground, with no added water, no reheating, no recirculation and no chlorination. The bicarbonate gives the water a distinctly slippery feel, and bathers who soak for a while find fine bubbles clinging to the skin. In the 2016 national onsen poll it placed third in the country for skin-softening water.

Bathing is indoors only, in separate mens and womens rooms, with no open-air tub. Each room holds two cypress baths kept at different temperatures, and the usual way to bathe is to move back and forth between the cooler and the warmer tub for a long, unhurried soak. The bath opens daily from 9:00 to 19:00, with last entry at 18:30, and closes on no fixed day. Admission is 700 yen for adults and 300 yen for elementary school children, with younger children free. There is a restaurant, a rest room and free parking on site. The building closed from October 2025 to March 2026 for structural repairs and insulation work, and reopened on 1 April 2026.