Hanayama Onsen Yakushi no Yu: Wakayama’s Extraordinary Carbonated Hot Spring
Located in Wakayama City, Hanayama Onsen Yakushi no Yu is one of Japan’s most remarkable naturally carbonated hot springs.
Its mineral-rich water rises from approximately 500 meters underground, propelled to the surface by the pressure of its own carbon dioxide rather than by mechanical pumping. Because of its exceptionally concentrated spring water, Hanayama Onsen is often described as “Kansai’s strongest carbonated hot spring.”
In this Premium Onsen Box, we introduce the Hanayama Onsen Yakushi no Yu Carbonated Bath Tablet, developed to bring an experience inspired by this celebrated hot spring into your home.
A Hot Spring So Rich Its Minerals Crystallize
Hanayama Onsen’s natural spring water contains carbon dioxide along with iron, calcium, magnesium, sodium, and other minerals.
The water is clear when it first emerges from underground, but gradually turns yellowish brown after coming into contact with the air. Over time, its abundant minerals form thick crystalline deposits around the baths—one of the hot spring’s most distinctive sights.
At Hanayama Onsen, guests also enjoy alternating between the approximately 26°C source bath and warmer baths. Known as onrei kōgo-yoku, or contrast bathing, this practice allows bathers to experience pools of different temperatures at a relaxed pace.
A Destination for Toji
Toji is a traditional Japanese wellness practice in which people stay at a hot spring for several days or weeks, bathing regularly while allowing their bodies and minds to rest.
Many guests visit Hanayama Onsen specifically for its distinctive carbonated spring and stay for an extended period. It is more than a sightseeing destination—it is a place to slow down, restore one’s energy, and reconnect with the body through Japan’s bathing culture.
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Hanayama Onsen Yakushi no Yu Carbonated Bath Tablet
This carbonated bath tablet is a Japanese quasi-drug bath product developed with reference to the mineral analysis of Hanayama Onsen.
It contains considerably more carbonation than many standard bath additives. Each tablet dissolves slowly over approximately 10 minutes, releasing fine bubbles throughout the bath. Entering the water immediately after adding the tablet lets you enjoy the gradual change as it dissolves.
Relax at home with a soothing bathing experience inspired by one of Wakayama’s most celebrated hot springs.
How to Use:
Add one tablet to approximately 200 liters of lukewarm water at around 38°C / 100°F.
The tablet will dissolve gradually over approximately 10 minutes. You may enter the bath immediately after adding it to enjoy the changing sensation as the tablet releases its bubbles.
To fully enjoy the carbonated bath, a leisurely soak of around 30 minutes is recommended, provided you feel comfortable. Take a break if necessary, stay hydrated, and leave the bath if you begin to feel unwell.
Active Ingredients:
Sodium bicarbonate, dried sodium sulfate, and dried sodium carbonate
Other Ingredients:
Succinic acid, titanium dioxide, PEG-6000, calcium carbonate, sodium oxide, magnesium sulfate, sucrose fatty acid ester, Yellow No. 4, Red No. 106, and fragrance
Indicated Benefits:
As stated on the product’s approved Japanese quasi-drug label, the bath tablet is indicated for relief from fatigue, stiff shoulders, lower-back pain, sensitivity to cold, neuralgia, rheumatism, rough skin, heat rash, eczema, acne, chilblains, skin cracks and fissures, hemorrhoids, bruises, sprains, and sensitivity to cold before and after childbirth.
Experience Japanese Toji at Home
In Japan, bathing is about more than cleansing the body. It is also an opportunity to slow down, rest, and restore a sense of balance.
With the Hanayama Onsen Yakushi no Yu Carbonated Bath Tablet, step away from the demands of everyday life and enjoy a peaceful moment inspired by Japan’s traditional toji culture.
Experience Japanese Toji at Home
In Japan, bathing is about more than cleansing the body. It is also an opportunity to slow down, rest, and restore a sense of balance.
With the Hanayama Onsen Yakushi no Yu Carbonated Bath Tablet, step away from the demands of everyday life and enjoy a peaceful moment inspired by Japan’s traditional toji culture.
