나카노사와 온천 오사카야

♨️Fiercely acidic sulfur water, a century of cure baths

Fukushima · Nakanosawa Onsen Iroriyu no Yado Osakaya

1

Japan's Greatest Flow

• 💧About 13,400 liters a minute from a single vent — the largest output in Japan
• 🌋Piped six kilometers from the Numajiri source at 1,200 meters on the flank of Mt. Adatara
• ♨️A hot acidic sulfur spring, 53°C at the source, served exactly as it comes

2

Strong Acid, Straight from the Source

• 🧪At pH 1.85 this is a powerfully antiseptic medicinal water
• 🚿Six kilometers of travel lets the gases escape and softens the water like repeated yumomi
• 💦One hundred percent Kakenagashi — clear some days, clouded with yunohana on others

3

The Cave Bath and the Rock Bath

• 🕳️The men's side has a dokutsu-buro cave bath with a proper hideaway feel
• 🪨Stretch out fully in the iwaburo rock bath and let the fatigue go
• ♨️The women's side has an ishiburo stone bath — each tub with its own character

4

Rooms with an Irori

• 🏮Modest Japanese rooms carrying the calm of an old onsen inn
• 🚻Choose between Japanese rooms with private toilets and standard rooms
• 👘Yukata are provided for the length of your stay

5

What the Water Is Said to Do

• 🩺Long recommended for stomach trouble, rheumatism, chronic skin conditions and atopy
• 🌿Poor circulation, women's ailments, joint pain — the range of uses built its reputation as a cure spa
• 🦠The acidity is strong enough that legionella is simply not a concern

6

The Inn's History

• 📜Open as an inn since 1886, and loved as a toji cure house ever since
• ⛰️The spring itself was found on the slopes of Mt. Adatara in the Bunroku era
• 🏔️A homey country inn in the heart of Nakanosawa Onsen

7

Around and About

• 🚗Roughly 22 minutes by car from JR Inawashiro Station
• 🎿Numajiri Ski Resort and the Inawashiro castle ruins are both close by
• 🏞️A spa hamlet held inside the wild country below Mt. Adatara

An old house in Nakanosawa Onsen where Japan's highest-volume source arrives at pH 1.85, undiluted and unrecycled. In the cave bath and the rock bath, a hundred years of toji tradition is still very much alive.

#NakanosawaOnsen#Osakaya#FukushimaOnsen#SulfurSpring#Kakenagashi#TojiCureBath#Inawashiro#CaveBath

* This introduction was compiled from information published by each property (official website and similar sources), so some details may differ from what you find on the day. It is AI-assisted and can contain errors — please check the official website and the details shown at booking before you reserve.

From onsen etiquette to check-in — the things worth knowing first.

Check In/Check Out Policy · Check In: 15:00 · Check Out: 10:00 · Last Check In: 21:00

* These policies are the property's own text, in English; the cancellation policy shown at booking takes precedence.