Ryokan Ohashi

A 1932 riverside inn registered as a cultural property, with a half-underground cave bath where radium and thorium water rises through the rock — unforgettable baths, uneven service

Ohashi was completed in 1932 from rare local timbers and stretches about 120 metres along the Mitoku river; nearly the whole inn — main building, two annexes, a 100-mat hall with a kabuki stage and an arched bridge — is a registered tangible cultural property. Rooms are named for the wood they're built from, such as Nanten with its umbrella-shaped ceiling of nandina, and the wavy hand-made window glass survives. The star is the Gankutsu-no-yu, a half-underground cave bath of three rock tubs where water wells up through the old riverbed: two radium springs and a thorium spring the inn says is unique in Misasa. The inn owns five sources and its baths are described as free-flowing, though one booking site notes water is added to cool the roughly 60°C spring. Japanese guests rate it 4.5 across 694 reviews on one major site and 4.41 across 279 on another, with baths and dinner scoring highest; winter brings Matsuba crab kaiseki. The complaints recur, though: rooms that are hot in summer and cold in winter, thin walls and river noise, standard rooms with no onsen bath, an uneven rock floor that's risky for unsteady guests, women able to use the cave bath only until 21:00, and signs of short staffing from 2022 to 2026 — slow check-in, an unstaffed front desk, a wrong crab course. One 2022 couple felt quality dropped after a chef change; 2025–2026 dinner reviews are mostly positive. Weekday rates start around ¥28,600 per person with two meals.