Zao Onsen Oomiya Ryokan

A Taishō-romance inn where every corridor and stair is tatami, with 100% free-flowing sulphur water from its own spring and Yamagata-beef dinners at a fair price — but the baths are small and crowd easily, there's no lift, and the open-air bath shuts all winter

Oomiya Ryokan claims a thousand years beside Zao's springs and dresses its 32-room house in Taishō-era (1912–26) nostalgia: colour-paned shōji-style windows, a Takehisa Yumeji print, and tatami laid through every corridor and staircase, so you walk barefoot from lobby to room. The inn calls its source Zao's biggest, about 720 litres a minute welling from a stone wall, and the inn says all its baths are 100% free-flowing strongly acidic sulphur water: an egg-shaped wooden tub, a spring bath with a bubble bath, and an open-air bath, swapped between men and women. Japanese guests rate it 4.48 across 1,182 scored reviews on Rakuten Travel (rooms, service, meals and baths all about 4.5) and 4.44 across 55 on Ikyu. They praise the barefoot comfort, the milky, prickly water, dinners built around a choice of Yamagata-beef sukiyaki, shabu-shabu or hot-plate grill with Tsuyahime rice, a free lounge, frequent room upgrades and a free shuttle from Yamagata Station. A June 2026 travelogue found the cheapest room on the third floor, about 15 tatami, with a view over the village. The complaints, dated 2025–2026: no lift (the acidic spring corrodes metal) and lots of stairs in a long, extended building; baths so small that three fill the egg tub, with only four washing stations; brusque front-desk replies; dust and an insect left in rooms; and some windows facing walls. The open-air bath closes from late November to early April. Two meals run about ¥15,400–21,000 per person; one June 2026 weekday early-bird stay cost ¥17,600.