Yanagawa Onsen (柳川温泉)

Introduction: The Forest Sanctuary of the Mountain Pass

Hidden deep in the forested foothills of the Dewa Range, in the town of Oe, lies Yanagawa Onsen (柳川温泉). Known as the “Gateway to Gassan,” this destination is the ultimate retreat for hikers and nature photographers. Yanagawa is geologically defined by its high-temperature Sodium-Chloride Springs that gush from a depth of 1,200 meters. The name “Yanagawa” (Willow River) reflects the serene, flowing energy of the area. Unlike the castle towns of the basin, Yanagawa is a place of raw alpine beauty—a single, high-quality facility surrounded by cedar forests and mountain streams. For the international traveler, Yanagawa Onsen represents the “Pure North”—a place to soak in waters that smell of the earth’s minerals while watching the seasonal changes of the Gassan peaks. As Yamagata gains global attention on the 2026 National Geographic Best of the World list, Yanagawa remains a vital secret for those seeking a profound, quiet connection to Japan’s wilderness.

Key Information Table

Address	〒990-1271 山形県西村山郡大江町大字柳川2272 / 2272 Yanagawa, Oe Town, Nishimurayama-gun, Yamagata
Google Maps	View on Google Maps
Mapcode for GPS	677 206 587*22 (Main Facility Parking)
Spring Quality	Sodium-Chloride Spring (High Temperature / High Salinity)
Benefits	Exceptional for relief from “Hiesho” (cold sensitivity), chronic joint pain, and recovery from intense hiking/trekking.
Access	30-minute taxi or town bus from JR Aterazawa Station (Aterazawa Line); 1 hour from Yamagata City.
Number of Ryokans	1 flagship integrated lodging and day-spa facility (Yanagawa Onsen Health Center).
Day-trip Bathing	6:30 AM – 9:00 PM; Fee: ~350 – 450 JPY.

The Healing Waters: The “Thermal Shield” of the Dewa Range

The water at Yanagawa Onsen is geologically prized for its heat and high concentration of salt. It is primarily a Sodium-Chloride Spring.

The “Warming” Science:

• The Salt Veil: The high salt content ($Na-Cl$) forms a microscopic “pack” on your skin, preventing the evaporation of sweat and trapping body heat deep within your core. This is vital for hikers returning from the snow-clad slopes of Mt. Gassan. [5, 1, 2]
• Circulatory Recovery: The warmth penetrates muscles and joints, making it a mandatory stop for those suffering from neuralgia or fatigue after a long-distance drive across the Yamagata mountains.

The facility features a spacious indoor bath with floor-to-ceiling windows and an outdoor Rotenburo where the steam blends into the mountain mist. To soak here during the “Ao-Momiji” (Green Maple) season in early summer or the “Koyo” (Red Leaf) season in October is a spiritual experience of the highest order.

Top Recommended Stays & Bases

• Yanagawa Onsen Health Center (大江町柳川温泉): Address: 2272 Yanagawa. This is the heart of the area. It is a large-scale, clean facility that offers both world-class thermal baths and comfortable, modern residential rooms. It is highly recommended for hikers who want a high-quality base with direct access to the healing waters.
• Aterazawa Historical District Guesthouses: Located 30 minutes away in central Oe, these renovated merchant houses allow you to experience the “Mogami River Town” culture before heading to the mountains for your soak.
• Gassan Base Camps: Several rustic lodges further up the pass provide a starting point for serious mountaineers, with Yanagawa serving as the final “civilized” bath before the summit.

Must-Visit Neighborhood Spots: Passports to the Past

Gassan Asahi National Park: Yanagawa is the gateway to the southern trails of Mt. Gassan. The trekking here is world-class, featuring rare alpine flora and otherworldly volcanic vistas.
Oe Town Townscape: Visit the “Kura” (storehouse) district of central Oe, where the wealth of the Mogami River trade is still visible in the architecture.
Shunkeii-ji Temple: A quiet temple in the hills of Oe known for its beautiful Zen garden and historical artifacts.

Local Gastronomy: The Mountain Bounty and Soba

Oe Town is part of the legendary “Yamagata Soba Corridor.”
Signature Dish: Try the “Yanagawa Soba”—thick, rustic noodles served with a side of foraged Sansai (Mountain Vegetable) Tempura.
Vegetarian/Vegan Survival: 
For Vegans: Yanagawa is a “Sansai Paradise.” At the onsen restaurant, request the “Local Vegetable Set” and specify “No fish stock” (Kombu-dashi nuki). The local “Oe Wild Mushrooms” are a staple of the regional vegan diet. Also, look for “Yanagawa Natto”, which is locally fermented and has a unique, robust flavor profile. [1, 4]

Cultural & Historical Context

Historically, Yanagawa was a vital checkpoint on the mountain trails connecting the inland basin to the spiritual peaks of the Three Mountains of Dewa (Dewa Sanzan). The onsen was developed to provide “Misogi” (purification) for the pilgrims and recovery for the forestry workers who managed the pass. Today, it remains a symbol of Oe Town’s commitment to sustainable wellness and environmental protection.

Practical Travel Tips for International Visitors

• Tattoo Policy: As a public health center, Yanagawa Onsen is relatively tolerant of tattoos. Small pieces are generally ignored; for large works, we recommend using a waterproof cover sticker or visiting during the early morning hours (6:30 AM).
• Connectivity: Free Wi-Fi is available in the main lobby. Mobile signal can be intermittent when exploring the deeper mountain trails.
• Cash & Payments: Entry is cash-only via a ticket machine. The restaurant and shop accept some electronic payments like PayPay, but JPY coins are needed for lockers.

2025-2026 Latest Updates

In 2025, Yanagawa launched the “Forest Bathing & Mineral Soak” program, where professional guides lead mindful walks through the cedar forests followed by a deep-core thermal soak. For the 2026 season, new “Starlight Viewing Platforms” are being installed to take advantage of the pass’s zero light pollution.

Safety & Manners

Mountain Weather: The weather in Yanagawa can change instantly. Always check the forecast before heading into the forest.
Winter Driving: The road to Yanagawa is a winding mountain pass that becomes perilously icy. 4WD and studless tires are mandatory from December to March.