Fukushima Travel – The Secret Source of Dake Onsen

Hidden in the mountains of Fukushima Prefecture, Dake Onsen in Nihonmatsu City is known for its beautiful milky white hot spring waters, which are rich in natural minerals and said to be healing for both body and soul. But few people know where this hot water truly comes from—or the dedicated efforts it takes to keep it flowing.

A Mountain Spring with a Story

The source of Dake Onsen is located near Kurogane Lodge (Kurogane Goya) on Mt. Adatara, a scenic volcanic mountain popular for hiking. The hot spring water travels over 8 kilometers down the mountain through a wooden aqueduct system called a yudoi (湯樋), all the way to the inns and ryokan of Dake Onsen village.

However, minerals in the water form “yubana” (湯花)—natural mineral deposits that can clog the pipes over time. That’s where the “Yumori” (湯守) come in.

The Guardians of the Onsen – Yumori

The Yumori are hot spring caretakers, responsible for climbing the mountain every week to inspect and clean the aqueduct. It’s a demanding job that requires both strength and deep respect for the hot spring tradition. Their work ensures the water flows clearly and consistently to the onsen below.

The trail to Kurogane Lodge starts from the Okudake Trailhead, and it takes just over one hour of moderate hiking to reach the site. The area around the source is normally off-limits to the public due to volcanic gas emissions, but on a special occasion, we had the rare opportunity to visit the site with the guidance of a Yumori.

What Happens After the Cleaning – The Milky Day

After cleaning, the buildup of mineral deposits is released into the water, turning the hot spring water a beautiful cloudy white. Locals and onsen enthusiasts call this “Milky Day”, a special time when the hot spring baths become especially scenic and rich in minerals.

Why Visit Dake Onsen?

• ・Experience an authentic Japanese hot spring powered by volcanic energy

• ・Learn about the hidden work of Yumori, the guardians of Japan’s traditional onsen

• ・Hike scenic Mt. Adatara, with views and nature year-round

• ・Soak in mineral-rich milky white waters—a rare and relaxing treat

• ・Discover a unique blend of nature, tradition, and culture in Fukushima travel

To explore places like Dake Onsen, and to experience local stories and behind-the-scenes traditions, we recommend traveling with Deep Japan Tours—offering guided tours through the hidden heart of Japan.

Dake Onsen isn’t just a hot spring—it’s a living tradition flowing from the mountains of Fukushima.

https://www.tif.ne.jp/hontabi/autumn/info.html?info=35