A terraced open-air bath along a mountain stream that holds 200 people, with bluish-white strongly acidic sulfur water. Open late April to late November only; closed in winter. Summer starlight sessions at night.
A Kengo Kuma-designed communal bath at the entrance to Ginzan's Taishō-era street. Hot water with drifting mineral flakes for ¥500. The one place day visitors can bathe in Ginzan's water — reception closes at 3:30 pm.
A log-cabin-style communal bath at the top of Takayu-dōri. Zao's three public baths (Kamiyu, Shimoyu, Kawarayu) all cost ¥200, paid into an honesty box. No washing stations — just rinse and sink into the strongly acidic milky sulfur water.
The large ryokan at the entrance to Ginzan. Indoor, open-air and lie-down outdoor baths — far roomier than Shirogane-yu. Day use 11:30 am–2 pm (last 1:30), ¥1,500, closed Thursdays; day bathing has been suspended and resumed repeatedly, so check the website. Cash only.
Hijiori Onsen, 1,200 years old, is a cure-spa where inns huddle at the bottom of a caldera in Ōkura village, Yamagata. Right in the middle of the street stands Kami-no-yu, the only communal bath open to visitors. A small bathhouse with an attendant's counter, it has slightly hot free-flowing sodium-chloride/bicarbonate water and a tiny Yakushi shrine in the corner of the tub. Adults pay ¥400 (free for guests of the village inns); open 08:00–18:00 (until 17:00 in winter), no bathing on Thursday mornings for cleaning. The Hijiori way is to pair it with the morning market that sets up from about 5–6 am (Apr–Nov). In winter this is one of Japan's snowiest places, and just walking the street between snow walls is an experience. About 55 minutes by bus from Shinjō Station.
Yunohama Onsen is a seaside spa on the Sea of Japan in Yamagata's Shōnai region. This municipal communal bath sits on the ground floor of the 'Cospa' community centre on the roundabout at the centre of the resort and is the locals' everyday bath. It uses a blend of Yunohama's springs — sodium-calcium chloride water — free-flowing with only a little dilution, in a single no-frills indoor tub. Adults pay ¥400; open in two sessions, 06:00–07:00 and 10:00–21:30, closed 2nd and 4th Thursdays. Soap and shampoo sold for ¥200, towels ¥100. The beach is two or three minutes' walk away, and the best plan is to watch the famous Yunohama sunset before soaking. About 35 minutes by bus from Tsuruoka Station.
The oldest of the communal baths surviving in the spa town of Kaminoyama, a former castle and post town about 10 minutes on foot from Kaminoyama-Onsen Station on the Yamagata Shinkansen. Moved to its present site in 1624, it is said to have been used by the Zen master Takuan. The big tub is split into hot and tepid halves, filled free-flowing with clear sodium-calcium-chloride-sulphate water. With its flagstone washing area and old-style attendant's counter, it charges an astonishing ¥150 for adults and ¥100 for children (hair washing ¥100 extra), and the tatami hall upstairs can be used for a day's rest for ¥300. Open 06:00–22:00 (from 06:30 December–February; last entry 21:30), every day. Take a morning or evening dip with locals while touring Kaminoyama Castle, the samurai-house street and the town's five foot baths. About 25 minutes by car from Yamagata city, 40 minutes from Zaō Onsen. No soap is provided, so bring your own; park in the shopping-street car park opposite.