A Rare Hakone Onsen ExperienceKappa Tengoku & Organic Odawara Mandarin Honey

Hello everyone,

For this edition of Onsen Box, we are delighted to bring back our much-loved Hakone Onsen Box, which was especially popular last year.

This time, we were able to secure something truly special:
rare organic mandarin honey from Odawara, a mountain village area near Hakone.

This honey is produced in very small quantities and is not available online, nor can it be purchased outside the region or overseas.
It comes directly from local beekeeper Asamidori, and it is a perfect expression of Hakone’s natural environment.

After visiting the beekeeper, we headed to a hidden hot spring near Hakone-Yumoto Station—
a place known only to locals: Kappa Tengoku.

The Power of Yuzu: A Citrus with Rich Tradition

Hakone is one of Japan’s most famous hot spring resorts.
However, as international tourism has grown, entrance fees and prices have increased significantly.

Kappa Tengoku is a rare exception.

For just 900 yen, you can enjoy an outstanding natural hot spring.
You will hardly see any foreign visitors here.
Instead, this is a bathhouse used daily by local Japanese people—a quiet, relaxed place where you can soak in peace.

The hot spring water is:

• not circulated
• not chemically disinfected
• constantly overflowing

Fresh water flows directly into the bath from near the bottom of the stone tub.

The water is clear and colorless.
If you scoop it with your hand, you may notice a faint mineral scent.
On the tongue, there is a subtle mineral taste.

Under the light, the surface of the water shimmers with a soft bluish glow—
a characteristic often seen in sulfate-rich hot springs.

The bathing sensation is unique:
smooth and silky, with a slight mineral firmness.
After bathing, warmth lingers deep in the body, while the skin feels smooth on the surface and moisturized from within.

In terms of mineral quality, this onsen is similar to classic hot springs found in northern Gunma Prefecture, such as Minakami and Yujuku.

A Rare Find in Hakone: True Free-Flowing Onsen

Hakone is home to many luxury spas and high-end hotels.
However, most of them rely on water circulation systems and chemical treatment.

Facilities that use pure, free-flowing natural spring water are surprisingly rare.

Kappa Tengoku is one of them.

A Bathhouse Lost in Time

The building itself is wooden and extremely simple.
Even in Japan today, this kind of atmosphere is becoming hard to find.

From the changing room alone, you can feel its charm.
The bathing area is even better.

It feels like a remote mountain healing retreat—
as if this place was quietly left behind, untouched by time, for the last 50 years.

A Perfect Example of “True Onsen”

There is a small outdoor bath built directly against a natural rock wall.

The water here meets the highest standard of what we call true onsen:

• no added water
• no heating
• no circulation
• no bath additives
• no disinfection

Fresh spring water flows directly into the bath without being exposed to air, maintaining excellent freshness.

In onsen terms, this is a perfect score.

Loved by Locals, Unchanged for Decades

Kappa Tengoku is not flashy.
It does not try to impress.

Instead, it offers what truly matters:
honest water, a calm atmosphere, and deep relaxation.

If you are looking for a genuine Japanese hot spring experience, this is a place worth visiting at least once.

A Special Gift in This Onsen Box

For this edition, we have included a limited-edition Kappa Tengoku commemorative towel, available exclusively through Onsen Box.

Onsen Details

Name: Kappa Tengoku
Hot Spring Type:
Alkaline Simple Spring / Sodium Chloride–Sulfate Spring
pH Level: 9.2 (highly alkaline)


Features:

100% free-flowing natural hot spring

Benefits:
Relief from muscle pain, neuralgia, minor wounds, chronic skin conditions, and more

Two private onsen sources

No dilution, no heating, no circulation

No bath additives, no chemical disinfection