Nupun Tomuraushi Onsen (ヌプントムラウシ温泉)

Introduction: The Phantom Wild Basin of the High Daisetsuzan Frontier

Deep within the most remote wilderness of the Daisetsuzan National Park, at the end of a harrowing 14-kilometer gravel forest road, lies Nupun Tomuraushi Onsen (ヌプントムラウシ温泉). This is not just a hot spring; it is the ultimate pilgrimage for the world’s most dedicated “Onsen Hunters.” Known as a “Phantom Onsen” due to frequent road closures and its absolute isolation, Nupun Tomuraushi offers a raw, primal encounter with Hokkaido’s volcanic soul. Here, the Nupun Tomuraushi River carves through a prehistoric valley where hot mineral water surges directly from the riverbed into a single, hand-built stone pool. For the international adventurer, this represents the “Final Frontier” of wellness: a place of absolute silence, where there is no mobile signal, no electricity, and no human presence—only the roar of the water and the ancient energy of the mountain gods. To soak here is to stand at the edge of the world, reclaimed by nature itself.

Key Information Table

The Healing Waters: The Boiling Pulse of the Riverbed

The water at Nupun Tomuraushi is geologically intense. It emerges from the rocky bank at temperatures near 90°C, requiring a careful mix with the ice-cold mountain stream to reach a swimmable 42°C. The spring is a Simple Sulfur type, clear but carrying that potent, earthy scent that signals volcanic purity. Because the pool is built directly into the riverbank using local river stones, you can feel the vibration of the rushing rapids while you soak. The mineral content is remarkably high for a simple spring, providing an immediate soothing effect on joints and muscles exhausted from the long, bumpy drive or mountain trekking. This is “Gensen Kakenagashi” in its most honest form—no pipes, no pumps, just the direct flow from the earth’s interior.

Top Recommended Bases & Logistics

Nupun Tomuraushi is strictly a “Day Expedition” destination. Travelers must use the surrounding towns as their base camp.

• Nukabira Gensen-kyo (1 hour away): The most logical base. Staying at Nukabira Onsen Nakamuraya provides a comfortable starting point and essential local knowledge regarding current forest road conditions.
• Shintoku Town Hotels: Located on the other side of the pass, Shintoku offers various guesthouses for those combining Nupun with the Tomuraushi hiking trails.
• Kamishihoro Campground: For the truly adventurous, camping in Kamishihoro and starting the drive at dawn is the best way to ensure you have the wild bath to yourself.

The Expedition Experience: The Long Road to the Phantom

The journey to Nupun Tomuraushi is as famous as the bath itself.
The Forest Road (Rindo): The 14km gravel track is narrow, prone to washouts, and strictly for high-clearance vehicles. You will drive through some of Hokkaido’s densest forests, where Ezo deer and foxes are your only companions.
The Ruined Lodge: Upon arrival, you will see the eerie remains of the former lodge, a haunting reminder of the power of Hokkaido’s typhoons. The bath itself sits just below these ruins by the river.
Mountain Scenery: The valley is framed by the steep, green walls of the Daisetsuzan interior, offering a scale of landscape that feels more like Alaska or New Zealand than Japan.

Local Gastronomy for Explorers: The Survival Kit

There are NO facilities, shops, or vending machines within 25km. Your nutrition must be entirely self-contained.
High-Energy “Pioneer” Meals: Before heading out, buy Tokachi Beef Jerky or Kamishihoro Potato Snacks at the local Roadside Station (Michi-no-Eki).
Vegetarian/Vegan Survival: Pack a bag of Roasted Hokkaido Soybeans and fresh local fruit.
Safety Note: **Never leave food out** at the site, and take every single piece of trash back with you to Obihiro or Kamishihoro. The scent of food can attract brown bears into the bathing area.

Cultural & Historical Context

The name “Tomuraushi” comes from the Ainu words referring to a place with many flowers or a place where the water is abundant. Historically, this site was a secret healing ground for Ainu hunters who followed the tracks of injured animals to the steaming riverbank. In the 20th century, a small lodge operated here, creating a legendary community of “mountain folk,” but after the lodge was reclaimed by nature in a massive storm, it returned to its original state as a “holy wild place.” Today, it is maintained by a small group of volunteers who ensure the stone tub remains safe for those brave enough to reach it.

Practical Travel Tips for International Visitors

• Road Status: **CRITICAL.** Do not attempt this drive without checking if the road is open. Contact the Kamishihoro Town Office or your hotel. After heavy rain, the road is almost always closed due to landslide risk.
• Vehicle: A standard rental car (compact) will likely sustain damage. Use a **High-Clearance 4WD (SUV style)**. Ensure you have a full tank of gas before leaving Kamishihoro.
• Tattoo Policy: As a wild, outdoor spot, there are no restrictions on tattoos. It is a place of total freedom.
• Bathing Style: Nupun Tomuraushi is a mixed-gender “No-yu” (Wild bath). While locals often bathe naked, wearing swimwear is permitted and highly recommended for international visitors to maintain a comfortable environment in this open space. There are no changing rooms; use your car or a large towel.

2025-2026 Latest Updates

In 2025, a new satellite-based emergency SOS station was installed at the entrance of the forest road to assist travelers who might get stranded. For the 2026 season, local volunteers are planning a “Wilderness Preservation Day,” inviting trekkers to help clean the valley in exchange for a guided history talk about the phantom lodge.

Safety & Manners

In the onsen, **never use soap or shampoo**—the runoff goes directly into the pristine mountain river. This is active Brown Bear territory—always carry a bear bell, stay alert, and never visit alone if possible. Finally, respect the “Phantom” nature of the spring; if the water is too hot or the river is flooding, do not take risks. The mountain is the master here.