What is the water temperature at Ikaho Onsen?

The water temperature at Ikaho Onsen is 38–55°C.

Is Ikaho Onsen free to enter?

Entry to Ikaho Onsen costs ¥410.

Are tattoos allowed at Ikaho Onsen?

Ikaho Onsen has a mixed or discretionary tattoo policy — contact them directly to confirm.

How do I get to Ikaho Onsen by train?

The nearest train station to Ikaho Onsen is Kamikanaihara kouminkanmae, approximately 0.1 km away.

Public · Indoor & Outdoor · ¥410

Ikaho Onsen

伊香保温泉

55°CPublic BathIndoor & Outdoorironsulfate

Official website Report issue

4.1· 1,900 reviewsvia Google

38–55°CWater temp

6.2pH

¥410 (~$3)Entry fee

PublicBathing type

—Opening hours

About this spring

A hilltop onsen town in Gunma Prefecture built along 365 stone steps that climb through a valley lined with inns and old shops. The iron-rich golden-brown waters have been used since the Nara period. The staircase is the town's spine: everything happens along it or just off it.

Data: Wikipedia (CC BY-SA 4.0) · OpenStreetMap (ODbL)

Highlights

365 historic stone steps
Golden iron-rich waters
Traditional ryokan streetscape
Natsume Soseki connection

Suitability

Tattoo policy

Policy varies

Children policy

Family-friendly

Altitude

700m

Mineral chemistry

Iron

Benefits

Iron-bearing springs are recognised by their characteristic rust-red or amber colour and metallic taste. The iron content — primarily ferrous bicarbonate or ferric sulfate — is associated with stimulation of red blood cell production and is traditionally recommended for anaemia and fatigue recovery. The distinctive colouring comes from iron oxidising on contact with air and is not a sign of contamination.

Note

Iron springs will stain light-coloured swimwear and towels a persistent brownish-orange. Avoid wearing white or light fabrics into the water. Those with haemochromatosis (iron overload condition) should seek medical advice before bathing.

Sulfate

Benefits

Sulfate springs (硫酸塩泉) contain dissolved calcium, sodium, or magnesium sulfate and are among the most therapeutically versatile spring types. Calcium sulfate springs are traditionally associated with wound healing and post-surgical recovery — the calcium ions support tissue repair and the sulfate has mild astringent properties. Sodium sulfate springs are linked to liver and digestive function; they are one of the few spring types used in Japan's national spa therapy clinics for chronic digestive complaints. The water typically has a clean, slightly bitter mineral taste.

Note

Sulfate springs are generally well-tolerated. Those with kidney stones of the calcium oxalate type should consult a doctor before bathing regularly. Sodium sulfate springs can have a mild laxative effect in sensitive individuals — stay hydrated.

History

These springs appear in the Man'yoshu poetry anthology compiled around 759 AD, suggesting the waters were already valued in the Nara period.

The stone staircase has a more martial origin. After his defeat at the Battle of Nagashino in 1575, the warlord Takeda Katsuyori ordered his general Sanada Masayuki to build the stairway as a system for distributing spring water to bathhouses along the route. Wounded soldiers needed both water supply and access to healing baths. During the Edo period the resort served domain lords and travellers seeking recuperation in the mountains. The Meiji and Taisho eras brought a new class of visitor: literary pilgrims. Natsume Soseki, Tokutomi Roka, Takehisa Yumeji, and Hagiwara Sakutaro all spent time here.

Local guide

From Shibukawa Station, the bus climbs the lower slopes of Mount Haruna and deposits you at the base of a stone staircase that runs three hundred meters straight up the center of the town. The steps are granite, there are three hundred and sixty-five of them, and the number is intentional: the town's wish that it stay busy year-round, every day of the year, pressed into the very architecture. On either side of the staircase, old inns and small restaurants have been here for the better part of four hundred years, and a narrow channel runs alongside the steps carrying water that looks nothing like water.

Ikaho's signature bath, Kogane no Yu, carries the highest iron content of any hot spring in Gunma Prefecture. The water comes out of the earth already loaded with dissolved iron, and when it hits oxygen it turns. By the time it reaches the tub it is a deep amber-brown, the color of weak tea darkened to opacity, sitting warm and faintly metallic at a pH of 6.2. At 38 to 55 degrees, the range covers everything from a slow, comfortable soak to something that requires you to lower yourself in slowly. On your skin the iron water feels heavier than plain water, not slimy but substantial, and it leaves the faintest mineral residue when you dry off.

There is a second spring in Ikaho, Shirogane no Yu, discovered more recently, which is clear and colorless. Both waters flow in separate pipes through the town, and the better bathhouses offer both. But the brown water is what people come for, and it runs openly through a channel visible right beside the stone steps so that even before you reach the bath you can smell the faint iron on the air and watch the rust-colored water moving down through the heart of the town.

Natsume Soseki spent time here in the Meiji period, along with several other writers of that era who found something useful in Ikaho's combination of mild mountain air and unusual water. The literary connection is mentioned on plaques near the top of the stairs, but the place does not make too much of it. On a weekday morning in autumn, when you climb to the top of the stone steps and look back down at the brown-water channel flanked by old wooden inn fronts and the forested slopes of Haruna framing everything behind, it earns itself on its own terms.