Yamagata Prefecture is known as a "Hot Spring Kingdom" with natural hot springs in all 35 municipalities. Among these, the hidden hot springs (hitou) hold special appeal due to their difficult access, high altitude locations, and solitary inn settings. Here are 10 remarkable hidden hot springs in Yamagata Prefecture.
1. Ubayu Onsen Masugataya (Yonezawa City, Yamagata)
Located at an altitude of 1,300 meters between Mt. Dainichi and Mt. Yakushi in the Azuma mountain range, this is the highest hot spring facility in Yamagata Prefecture. Founded in 1533, it has approximately 500 years of history. According to legend, the first innkeeper discovered the spring when guided by a mountain hag (yamauba) while searching for gold mines, which is the origin of the inn's name.
The mixed outdoor bath "Yamauba no Yu" is surrounded on three sides by towering cliffs and unusual rock formations, offering an incomparable view. The indoor bath features separate cypress baths for men and women, and there are three outdoor baths, all fed by free-flowing source water. The milky white warm water is characteristic, with attractions varying by season - fresh greenery in spring, summer retreat from heat, and autumn foliage.
To reach the inn from the parking lot requires a 15-20 minute walk along a mountain path, truly earning its designation as a hidden hot spring among hidden hot springs. The building was renovated between 2004 and 2005 into an attractive mountain lodge style.
- Spring Quality: Simple acidic sulfur spring
- Free-flowing source water
- Baths: Indoor = separate for men and women, Outdoor = 3 (1 mixed, 2 women-only)
- Source Temperature: 63°C
- Water Volume: 720 liters/minute
- No dilution or heating
- Day-use bathing: Available (Adults 600 yen, 9:30-15:30, outdoor baths only)
- Accommodation: Available (From 13,542 yen per night with 2 meals)
- Operating Period: Late April to early November (Closed in winter)
2. Zao Onsen (Yamagata City, Yamagata)
Discovered around 110 AD by Kibi no Tagayu, who accompanied Yamato Takeru on his eastern expedition, this ancient hot spring has approximately 1,900 years of history. Located at an altitude of 880 meters, it was formerly called Mogami Takayu or Takayu, and is counted as one of the "Three Great Hot Springs of Oshu" along with Takayu Onsen in Fukushima and Shirabu Onsen.
The area has 47 springs branching from five source groups, with an abundant flow of approximately 5,700 liters per minute, totaling about 8,700 tons per day - one of the largest outputs in Japan. The water is strongly acidic sulfur spring with pH 1.5-1.6, the second most acidic in Japan. Due to this strong acidity and powerful cleansing and bleaching properties, it is known as "hot spring for creating beauty," with effects that whiten and smooth the skin.
The hot spring town has three public bathhouses (Kamiyu, Shimoyu, Kawaharayu), with Kawaharayu being particularly notable as the source water springs directly from the bottom of the bath. From spring to autumn, the "Zao Onsen Dai-Rotenburo" (Large Outdoor Bath) opens, where 200 people can bathe at once while enjoying forest bathing.
Adjacent to one of Japan's largest ski resorts, Zao Onsen Ski Resort, the area becomes a bustling comprehensive mountain resort with ski visitors in winter, making it the largest in the Tohoku region.
- Spring Quality: Acidic, sulfur-containing aluminum sulfate-chloride spring
- Free-flowing source water (varies by facility)
- Baths: 3 public bathhouses, 5 day-use facilities, 66 accommodation facilities
- Source Temperature: Varies by spring
- pH: 1.5-1.6
- Day-use bathing: Available (Public bathhouses 200 yen, Large outdoor bath 550 yen, etc.)
- Accommodation: Available (Many lodging facilities)
- Operating Period: Year-round
3. Namekawayu Onsen Fukushimaya (Yonezawa City, Yamagata)
A hidden hot spring at approximately 900 meters altitude, located at Itaya Pass in the Azuma mountain range. Part of the Yonezawa Hachito (Eight Hot Springs of Yonezawa), this solitary inn stands quietly along the mountain stream, featuring the spectacular Namekawayu Great Falls with an 80-meter cascading waterfall and beautiful valley streams. With over 200 years of history, the 14th generation now serves as the keeper of the hot spring.
The inn has no electricity or running water, relying on hydroelectric power and water storage tanks - a truly fitting environment for a hidden hot spring. With three private source springs, all baths use free-flowing source water. The bluish-white cloudy water is gentle on the skin, with a neutral pH sulfur-sodium-calcium-bicarbonate-sulfate spring that is comfortable for extended bathing.
Facilities include rock baths along the mountain stream, cypress baths, and indoor baths. The large outdoor bath has designated women-only hours from 16:00-17:30 and 9:00-11:00. Retaining the strong atmosphere of an old-fashioned hot spring cure resort, self-catering hot spring therapy is also possible, making it ideal for advanced hot spring enthusiasts.
- Spring Quality: Sulfur-containing sodium-calcium-bicarbonate-sulfate spring
- Free-flowing source water
- Baths: Indoor = separate for men and women, Outdoor = large outdoor bath, cypress bath
- Source Temperature: Natural spring
- Day-use bathing: Available
- Accommodation: Available (From 22,506 yen per night with 2 meals)
- Operating Period: Late April to early November (Closed in winter)
4. Shintakayu Onsen Azumaya Ryokan (Yonezawa City, Yamagata)
A solitary inn located at 1,126 meters altitude at the foot of Mt. Tengendai in the Nishi-Azuma mountain range. The elevation is easy to remember as "Ii-furo" (good bath - 1126). Within a 1-kilometer radius, there are no other buildings - truly an isolated hidden hot spring. The location was chosen as the flattest buildable area closest to the source spring, offering the finest hot spring environment in exchange for difficult access.
With five outdoor baths and one indoor bath, all use 100% free-flowing source water. The "Panoramic Outdoor Bath" offers views of Mt. Kabuto, a landmark of Yonezawa's town layout, with the Iide-Asahi mountain range visible in the distance. Other unique baths include the "Root Bath," carved from a 250-year-old chestnut tree, and the "Waterfall Viewing Bath" overlooking Shirogane Falls.
The private bath features concentrated cloudy water from a separate single source different from the other baths. In winter, snow makes access difficult for regular vehicles, requiring transportation by the inn's shuttle vehicle named "Enterprise." The steep mountain road ride feels like an amusement park attraction before revealing another world.
- Spring Quality: Sulfur-containing calcium-sulfate spring
- Free-flowing source water
- Baths: Indoor = separate for men and women, Outdoor = 5 (3 mixed, 1 women-only, 1 private)
- Source Temperature: 55.6°C
- Day-use bathing: Available (Adults 500 yen, under junior high 250 yen, 13:00-16:00)
- Accommodation: Available
- Operating Period: Year-round (shuttle required in winter)
5. Ohira Onsen Takimiya (Yonezawa City, Yamagata)
A hidden hot spring among hidden hot springs, located at 1,050 meters altitude in the Azuma mountain range south of Yonezawa City, among peaks including Nishi-Daizan and Tojuro. Discovered by a hunter in 860 AD according to legend, it has over 1,100 years of history. Overlooking the headwaters of the Mogami River, it is renowned for its efficacy for gastrointestinal ailments.
Vehicle access is impossible - visitors must walk 15-20 minutes from the parking lot along mountain paths and cross a suspension bridge over the valley to reach the destination. While the approach is downhill, the return requires approximately 30 minutes of uphill walking, making an overnight stay recommended for a leisurely experience.
The outdoor bath along the Mogami River headwaters, built with naturally stacked stones, offers views of the valley's beauty through the four seasons. The indoor bath provides views of the famous "Kaen-no-Taki" (Flame Falls), drawing from a different source than the outdoor bath. The environment, monopolizing the surrounding nature, creates unforgettable memories of a mountain night.
- Spring Quality: Sodium-chloride spring
- Free-flowing source water
- Baths: Indoor = 1, Outdoor = 1
- Source Temperature: Natural spring
- No dilution or heating
- Day-use bathing: Available (500 yen, 10:00-16:00)
- Accommodation: Available (From 12,744 yen per night with 2 meals)
- Operating Period: Late April to early November (Closed in winter)
6. Shirabu Onsen Azumaya (Yonezawa City, Yamagata)
With over 700 years of history, this is counted as one of the "Three Great Hot Springs of Oshu" along with Shinobu Takayu Onsen in Fukushima and Mogami Takayu (Zao Onsen) in Yamagata. Located at 850 meters altitude in a mountain retreat worthy of being called a hidden place, it has been beloved as a hot spring cure resort since ancient times.
The signature "Waterfall Bath" is spectacular, with hot water cascading from a height of approximately 3 meters, providing massage effects while fresh source water continuously fills the bathtub. The bathtub has been in use for over 400 years and was used by the first Yonezawa Domain lord, Uesugi Kagekatsu, and the famous benevolent lord Yozan.
The three thatched-roof inns - Azumaya, Nakaya, and Nishiya - were symbolic of Shirabu Onsen as former regular lodgings of the Uesugi Yonezawa Domain lords. However, Azumaya and Nakaya were destroyed by fire in 2000. Azumaya was subsequently rebuilt as a Japanese-style inn. Stone baths carved from large rocks and separate outdoor baths for men and women offer diverse hot spring experiences.
Meals feature local specialty Yonezawa beef in sukiyaki, shabu-shabu, or steak options, along with mountain delicacies and river fish varying by season.
- Spring Quality: Calcium-sulfate spring
- Free-flowing source water
- Baths: Indoor = separate for men and women, Outdoor = separate for men and women
- Source Temperature: Approximately 70°C
- Day-use bathing: Available
- Accommodation: Available
- Operating Period: Year-round
7. Shirabu Onsen Nishiya (Yonezawa City, Yamagata)
The only remaining old inn with a thatched roof in Shirabu Onsen. The approximately 200-year-old thatched hip-and-gable roof main building from the Edo period, combined with the approximately 80-year-old main building in aristocratic mansion style, creates an imposing presence. The sunken hearth in the open lobby of the main building, along with polished pillars and handrails, convey the weight of history and the warmth of wood.
The bathhouse, built in the late Edo period with granite, includes remnants of the hot spring cure resort with waterfall bathing, where natural hot springs have continuously overflowed into the bathtub for 700 years unchanged. Retaining the strong atmosphere of former hot spring cure resorts, visitors can relax thoroughly in the abundant hot springs and the slow flow of time.
The owner's dedication to preserving the value of old things for future generations is evident throughout, offering modern people living in waves of modernization a moment of human reconnection and self-reflection.
- Spring Quality: Calcium-sulfate spring
- Free-flowing source water
- Baths: Indoor = separate for men and women, Outdoor = available
- Source Temperature: Approximately 70°C
- Day-use bathing: Available
- Accommodation: Available
- Operating Period: Year-round
8. Hijiori Onsen Motokawaragawa (Okura Village, Mogami District, Yamagata)
Hijiori Onsen has 1,200 years of history, originating from a legend about an old monk who fell from a cliff, broke his elbow, and healed the injury by soaking in the hot springs that bubbled up there approximately 1,200 years ago. Hot springs effective for fractures and wounds actually spring forth, and it has prospered as a hot spring cure resort since ancient times.
Motokawaragawa is located along the Dozangawa River, with attractions including a woody-scented entrance and dining area with a sunken hearth creating a comforting atmosphere. The observation bath on the top floor overflows with a mixture of private source and cooperative source springs, while the private bath on the first floor along the river features a Shigaraki-yaki bathtub with only heated private source water.
The spring quality includes sodium-chloride spring and bicarbonate spring types, known as "cosmetic hot spring," "beautiful skin hot spring," and "warming hot spring." Cuisine features premium wild vegetables grown in the sacred waters of Mt. Hayama and local heirloom vegetables, delivering seasonal mountain flavors with heartfelt care.
From spring to autumn, the famous morning market opens, where strolling in yukata and geta fits the old-fashioned hot spring atmosphere. The natural beauty of Okura Village, registered as "One of the Most Beautiful Villages in Japan," is also appealing.
- Spring Quality: Sodium-chloride spring, Sodium-bicarbonate spring
- Free-flowing source water
- Baths: Indoor = separate for men and women, Private bath = 1
- Day-use bathing: Available
- Accommodation: Available (From 18,700 yen per night with 2 meals)
- Operating Period: Year-round
9. Hijiori Onsen Maruya Ryokan (Okura Village, Mogami District, Yamagata)
Known as a "hideaway for adults" with only 7 rooms. Hijiori Onsen features three source springs (Sources No. 1, 2, and 5) each with different spring qualities. Maruya's water is sodium-chloride spring with high moisturizing effects that warm the body to the core - a "warming hot spring."
The public bathhouse "Kamiyu" directly in front uses sodium-bicarbonate spring, highly alkaline, which emulsifies old skin cells for smooth skin - a "beautiful skin hot spring." At Maruya Ryokan, guests can enjoy both "detox" and "moisturizing" benefits.
The outdoor bath and cypress box bath in the Gassan guest rooms use 100% free-flowing source water. The private bath is available 24 hours at any time. A "cypress bath" was also newly installed with the 2018 renovation.
Cuisine centers on natural locally-sourced wild vegetables and organic pesticide-free vegetables nurtured by the spring water of sacred Mt. Gassan. Guests can savor seasonal flavors woven by Hijiori Onsen, from spring wild vegetables to autumn mushrooms.
- Spring Quality: Sodium-chloride spring
- Free-flowing source water (outdoor bath, Gassan rooms)
- Baths: Indoor = separate for men and women, Outdoor = 1, Private bath = available
- Day-use bathing: Available
- Accommodation: Available
- Operating Period: Year-round
10. Ginzan Onsen Notoya Ryokan (Obanazawa City, Yamagata)
A hot spring discovered by miners of the Nobesawa Silver Mine that flourished during the Keicho period (1596-1615). The town retains its Taisho-era streetscape, with magnificent cultural heritage-class wooden buildings lining the streets. At night, gas lamps cast warm light, creating a fantastical scene. The retro scenery, as if time-traveling, captivates many tourists.
The hot spring town features 3-4 story wooden inns lining both banks of the Ginzan River, truly embodying the world of Taisho Romance. Visitors can enjoy photogenic strolls in rental kimonos.
The spring quality is sodium-chloride-sulfate spring with a source temperature of approximately 60°C. Each inn offers free-flowing source water baths, where visitors can enjoy hot springs alongside the valley beauty that shows different expressions through the four seasons. The winter snow scenery is particularly beautiful, with the hot spring town wrapped in a silver world offering exceptional charm.
Access is approximately 40 minutes by bus from Oishida Station. Many inns operate shuttle buses from Oishida Station, a stop on the Yamagata Shinkansen.
- Spring Quality: Sodium-chloride-sulfate spring
- Free-flowing source water (varies by facility)
- Baths: Varies by inn
- Source Temperature: Approximately 60°C
- Day-use bathing: Available (varies by facility)
- Accommodation: Available (many lodging facilities)
- Operating Period: Year-round
Conclusion
The hidden hot springs of Yamagata Prefecture each possess unique histories and characteristics, continuing to fascinate visitors. The hidden hot springs scattered throughout mountainous areas above 1,000 meters altitude are treasuries of natural environments protected by difficult access and hot spring culture preserved by keepers over hundreds of years.
Hidden hot springs in mountain areas, including the Yonezawa Hachito, often close during winter, with spring through autumn being the optimal visiting period. Meanwhile, Zao Onsen and Ginzan Onsen operate year-round, with bathing amid winter snow scenery being particularly exceptional.
The information provided represents the latest available at the time of research, but errors may exist. Please confirm the most current information through official websites.