Shibu Onsen Kokuya

A 400-year-old wooden inn sitting on its own springs, where all eight baths — including a room of six hinoki tubs, one per spring — are booked privately for free; expect stairs and no lift, a maze of corridors and scalding water

Kokuya began in the early Edo period as a grain merchant's house, and each owner since has taken the name Ichizaemon; today's wooden three-storey building grew out of a 1957 structure on a slope in the centre of Shibu Onsen. The draw is water: the inn owns six springs, two rising beneath the building (you can see one through a glass floor panel), and in Fukuroku-no-yu each flows unmixed into its own hinoki tub, so you can bathe in all six side by side. Every one of the eight baths is now private — 45-minute slots booked at check-in from 15:30 to 21:15, then free to use whenever empty until checkout — and even the showers run on spring water. Ten rooms add their own free-flowing open-air bath, and since April 2023 a 140㎡ suite, Kuon, has its own gate, sauna and in-room dining. Japanese guests rate it 4.7 across 205 reviews on one major site and 4.09 across 289 on another, where baths score 4.55 but rooms only 3.55 and facilities 3.64. Bloggers from 2023 to 2025 praised the private bath-hopping, the key to Shibu's nine public bathhouses, Shinshu beef and the rice. The complaints, 2025–2026: no lift and endless stairs, parking a walk away and hard to find, baths too hot to enter without adding cold water, staff mix-ups, weak Wi-Fi, ageing rooms, and — on a 2026 Kuon stay — disappointing food. Two-meal plans run about ¥21,000–30,000+ per person.