Futamata Onsen (二岐温泉)

Introduction: The Ancient “Two-Pronged” Secret and the Gushing Bedrock of Mount Niki

Hidden deep within the primeval beech forests of the Ten-ei Highlands, at an altitude of 800 meters, lies 二岐温泉 (Futamata Onsen). This destination—a flagship member of the “Japan Society for Preserving Secret Hot Springs”—is a geological marvel that has flowed continuously since the Heian period (opened in 969).[13, 14] The name “Futamata” (Two-pronged) refers to its location at the fork of the Futamata River and the twin peaks of Mount Niki. Unlike modernized resorts, Futamata is defined by its “Gensen-ana-buro”—natural rock baths where the water gushes directly from the bedrock beneath your feet.[13, 15] For the international traveler, Futamata represents the “Final Frontier” of Japanese bathing. It is a place to breathe in the high-oxygen air of ancient forests, soak in “Mineral Life” while the river roars beside you, and experience the warm, unpretentious hospitality of a village that has guarded these healing waters for over a millennium.[16, 13]

Key Information Table

The Healing Waters: The “Feet-First” Mineral Surge

The water at Futamata Onsen is geologically prized for its absolute mineral purity and “newborn” freshness. It is primarily a Calcium-Sulfate Spring.[19]
The Bedrock Experience: At Daimaru Asunaro-so, the “Jibun-Iwa-buro” features a tub built directly over a rock fissure. The water rises from the earth’s crust and enters the bath without ever touching pipes or the air—retaining its full therapeutic potency.[13, 15]
The Restoration Effect: Sulfate ions are scientifically recognized for promoting collagen production and skin cell repair, while the calcium content provides a sedative effect on the heart and blood vessels—earning it the name “The Stroke-Prevention Spring”.[20, 21]
To soak in the “Mountain Stream Rotenburo” as the emerald green waters of the Futamata River rush past is a sensory immersion that defines the high-altitude wellness of Tohoku.[13, 14]

Top 5 Recommended Stays & Bases

• Daimaru Asunaro-so (大丸あすなろ荘): Address: 5 Shimonutamata. A legendary inn and member of the “Secret Onsen Society.” It features the famous “Pothole Rock Bath” and world-class Kaiseki cuisine served in private rooms.[13, 15]
• Ten-ei-yu (天栄湯): A hyper-exclusive hideaway that accepts only one group per day. It is the only inn that draws from the specific “gold-vein” cold spring of Ten-ei, famous for skin tightening.[13, 14]
• Hinoki-buro no Yado Bunke (ひのき風呂の宿 分家): A 150-year-old inn with thatched-roof aesthetics. As the name suggests, every bath is made of high-quality Hinoki cypress, offering a rich, forest-scented soak.[16, 13]
• Kashiwaya Ryokan (柏屋旅館): A warm, family-run establishment along the gorge with 5 distinct hot spring sources. It offers 24-hour access to its mineral baths.[15]
• やすらぎの宿 桂祗荘 (Katsuragisou): Known for its home-like atmosphere and friendly English support for international hikers exploring the nearby peaks.[17]

Must-Visit Neighborhood Spots: Emerald Gorges and Gold-Medal Rice

Futamata Gorge: A 5-minute walk from the parking lot. These emerald green streams pouring into rocky basins create a mystical scenery perfect for nature photography.
Wakui no Shimizu Spring: A mystical spring producing 2,200 liters of pure mountain water per minute, located near the village center.
Hatoriko Kogen: A short drive away, offering cycling and SUP (Stand-up Paddleboarding) on Lake Hatori during the summer months.
Roadside Station Ki-no-Sato Ten-ei: The best place to buy “Ten-ei Rice,” a multi-year gold-medal winner at international tasting competitions.

Local Gastronomy: The Kingdom of Mutton and Mountain Vegetables

Food in the Ten-ei highlands is defined by the purity of its snowmelt water.
Ten-ei Mutton Curry: A local specialty using high-quality lamb/mutton and aromatic “Maca” roots. Try the “Mixed Curry” at the Hatoriko rest stop.
Shirakawa Seiryu Pork: Premium pork raised with mountain spring water, often served as “Shabu-shabu” in the ryokans.
Vegetarian/Vegan Survival:
Roadside Station Ki-no-Sato: The attached restaurant serves “Ten-ei Yacon” dishes. Yacon is a root vegetable known for its sweetness; request the “Yacon Salad” or “Mountain Vegetable Tempura” without egg.
Private Kaiseki: When booking Daimaru Asunaro-so or Ten-ei-yu, specify “Vegan-shojin” 3 days in advance. They can prepare elaborate multi-course meals using local matsutake mushrooms and wild mountain herbs.[13, 14]

Cultural & Historical Context

Futamata Onsen’s history is anchored in its isolation. During the feudal era, it was a “Hidden Spring” for samurai seeking to heal their battle wounds in secret. The preservation of the 1,200-year-old **Iwase Yumoto** district nearby, with its row of thatched-roof inns, provides a visual bridge to a Japan that has largely disappeared in modern cities.[16, 13]

Practical Travel Tips for International Visitors

• Tattoo Policy: Ten-ei-yu is private-only (1 group per day), meaning it is 100% Tattoo-Friendly. Kashiwaya and Daimaru offer private rental baths, making them safe options for “inked” travelers.[13, 15]
• Connectivity: Mobile signal is stable, but high-speed Wi-Fi is rare in older wooden buildings. Carry a Portable Wi-Fi.
• Access & Rental Car: A Rental Car from Shin-Shirakawa Station is highly recommended, as local buses are infrequent and require reservations. In winter, Winter Tires are mandatory for the steep mountain road.
• Cash: Strictly Cash-Only (JPY) for local shops and roadside stations. Ryokans generally accept major credit cards for room payments.

2025-2026 Latest Updates

In 2025, Ten-ei launched the “UNESCO Highland Meditation” program, offering forest-bathing sessions starting from Futamata Gorge. For the 2026 winter season (Feb 21), the “Snowshoe Footpath Event” will guide visitors through the frozen beech forests directly from the onsen area.

Safety & Manners

Because the spring water rises directly from the bedrock, the floors are unusually slippery; walk with extreme caution. Ten-ei is a designated wildlife sanctuary; always carry a bear bell when walking the Futamata Valley trails. Finally, respect the silence of the “Secret Onsen”; these inns are for deep healing and meditative rest.