Kurogane Onsen / Dake Onsen (くろがね温泉/岳温泉)

Introduction: The 1,200-Year Legacy of the “Yumori” and the Milky Waters of Adatara

Perched on the rugged eastern slopes of Mt. Adatara, Dake Onsen (岳温泉)—fueled by the legendary Kurogane (くろがね) spring—is a place where nature’s fury is distilled into healing peace. This is one of Japan’s most geologically fascinating hot springs. The water is drawn from a source 1,500 meters high on the mountain and travels through an 8-kilometer pipe, naturally “massaging” the water and cooling it to the perfect temperature by the time it reaches the village below. For the international traveler, Dake Onsen offers a rare encounter with the Yumori (Water Guardians), a 200-year-old lineage of craftsmen who risk their lives in sub-zero blizzards to maintain the pipes. Whether you are here for the weekly “Milky Day” or as a base for conquering the Adatara peaks, this acidic highland sanctuary promises a transformative experience of volcanic power and human dedication.

Key Information: The Gateway to Highland Healing

The Healing Waters: The “Natural Peeling” of Kurogane

The water at Dake Onsen originates near the Kurogane Hut. With a pH of 2.50, it is highly acidic, which acts as a natural exfoliant for the skin. This process removes old keratin and stimulates cell renewal, earning it the title of “Beauty Water.”

• The 8-Kilometer “Tub Pipe”: The journey from the source naturally aerates the water, making it surprisingly gentle on the skin despite its high acidity.
• Milky Day (Weekly): Once a week, the Yumori clear the pipes of “Yunohana” (mineral flowers), causing the water to turn a rich, milky white. This event is so popular that travelers often plan their entire trip around it. [11]

Top 5 Recommended Stays in the Dake Highlands

• Kounkaku (光雲閣): Situated on a high ridge, this inn offers panoramic views of the Abukuma mountains and 100% free-flowing acidic water. [13]
• Azumakan (あづま館): The area’s premier resort, featuring a popular bakery and shop, “Dake Peak,” where you can sample local sake. [13]
• Soranoniwa Resort (空の庭リゾート): Focused on wellness, this hotel features “super-clay” baths and an organic-focused buffet. [13]
• O宿 Hana-kanzashi (花かんざし): A luxury wooden inn built in the early 20th century, offering a private and refined Japanese atmosphere. [11, 13]
• mt.inn (マウント イン): An active hiker’s hub that is exceptionally welcoming to international guests and mountain bikers. [13, 14]

Gastronomy: Volcanic Confections and “Nature” Dining

The culinary scene in Dake Onsen is deeply connected to the Adatara mountains:

• Kurogane-yaki: A fluffy, bean-filled cake that has been made by the same shop for over 70 years—famously presented to the Imperial family.[12]
• Adatara Mochi: Herb-infused rice cakes that are a must-try for any hiker returning from the peaks. [12]
• Vegan/Vegetarian: Soranoniwa Natural Restaurant: Offers creative European-style dishes using fresh vegetables from local contract farmers. It is the best place in town for healthy, plant-focused meals.
• Hao Nguyen Shop: A unique Vietnamese restaurant in the village offering Pho and Banh Mi, often featuring fresh local vegetables. [15]

Historical & Cultural Context: The Guardians of the Water

Since the Heian period (900 years ago), Dake Onsen has relied on the Yumori.[16, 11] These dedicated craftsmen walk deep into the snowy mountains to clean the pipes, a tradition that was vital even during the 2011 earthquake recovery.[11] The history of the area is also one of survival; the 1900 eruption of Mt. Adatara destroyed original lodges and killed dozens of miners, forcing the community to rebuild in its current location—a testament to their unbreakable spirit. [17]

Practical Travel Tips for International Visitors

• Tattoo Policy: mt.inn and Koito Ryokan are notoriously tattoo-friendly. For public baths like “Dake-no-yu,” small tattoos are acceptable if covered with stickers.
• Connectivity: Wi-Fi is reliable in most hotel lobbies, but if you are hiking to the source, be prepared for a “digital detox” as signals fade. [9]
• Cash & Payments: While major hotels take credit cards, the public baths and local souvenir shops like Tamagawaya are strictly cash-only (JPY). [12]
• Jewelry Warning: The high acidity will tarnish silver instantly. Remove all jewelry before entering the baths.

2025-2026 Latest Updates: The Kurogane Hut Rebuild

RENOVATION ALERT: The legendary Kurogane Hut (くろがね小屋) is currently being rebuilt. Due to construction challenges and costs, the completion has been delayed from 2025 to early 2028. During this period, there is no access to the hut, its toilets, or its baths. However, the Adatara Ropeway remains fully operational, providing spectacular views of the autumn foliage.

Safety & Manners

Mt. Adatara is an active volcano; always check for volcanic gas warnings before hiking near the source area. [17] In the winter, the “Snow Rabbit” (Yukiusagi) shape on the mountain signals the arrival of spring, but until then, mountain roads are treacherous and require winter tires.[10, 21] In the bath, remember that Dake’s water is acidic; do not rub your eyes with wet hands.