Okuno Hosomichi

A nineteen-room inn above the Arima hot-spring town, ringed by its three mountains, with terraces facing Mt Yubunedani and fireflies in early summer. Every room in the main building has its own open-air hot spring bath and terrace — three fed with Arima’s gold spring (金泉), eight with the inn’s own source. Annex rooms are simpler, and the plainest have no bath.

The gold spring comes from the Gokuraku source: an iron-bearing sodium chloride spring, pH 6.4, about twice as salty as seawater. It fills the open-air tubs of both communal baths, while the indoor tubs take the inn’s own source, colourless at pH 6.82. Each bath has a sauna and a cold plunge; the two swap between men and women, open 15:00–24:00 and 6:00–10:00. The inn says both run free-flowing, while listings it supplies record the water as diluted, heated and filtered — its own accounts disagree. A bath reservable by annex guests, gold spring outside and heated plain water inside, is 5,000 yen for 50 minutes on the day you arrive.

Dinner is 客前料理, courses finished in front of you by owner-chef Tadamichi Ota, decorated by the state in 2004 and 2012. The 雲海鍋, a “sea of cloud” hotpot, stands wagyu sukiyaki on candyfloss. Both meals are served in a dining room partitioned by shoji screens.

Check-in 15:00–19:30, check-out 11:00; arrive after 20:30 and dinner cannot be served. Free pickup from Arima Onsen station. Two guests minimum, and online bookings exclude children of primary-school age and under.