Bicarbonate spring

Tokachigawa Onsen

十勝川温泉

Hokkaido · 100 Onsen to Know Japan — No. 6

Not volcanic heat but ancient plants: the brown, silky 'moor' spring that defines the type in Japan.

Toyotomi Onsen

豊富温泉

Hokkaido · 100 Onsen to Know Japan — No. 5

They drilled for oil and struck hot water: an amber, petrol-scented spring that draws long-stay bathers from all over Japan.

Noboribetsu Onsen

登別温泉

Hokkaido · 100 Onsen to Know Japan — No. 1

Ten thousand tonnes of water a day and nine kinds of spring, all boiling out of a single valley called Hell.

Marukoma Onsen

丸駒温泉

Hokkaido · 100 Onsen to Know Japan — No. 4

The bath is exactly as deep as Lake Shikotsu is high that day: an open-air tub joined to the lake.

Tsuta Onsen

蔦温泉

Aomori · 100 Onsen to Know Japan — No. 10

The spring bubbles up between the floorboards of the bath itself: a thousand-year-old hot spring at a lone inn in a beech forest.

Naruko Onsen

鳴子温泉

Miyagi · 100 Onsen to Know Japan — No. 18

Seven of Japan's ten official spring types in one valley. The communal Takinoyu by the station costs 300 yen, and the town lends you wooden geta to clatter from bath to bath.

Tsurunoyu Onsen

鶴の湯温泉

Akita · 100 Onsen to Know Japan — No. 14

Below a thatched guardhouse, a milky-white pool bubbles up from the ground beneath your feet. This is the oldest inn in the Nyuto hot-spring valley.

Hijiori Onsen

肘折温泉

Yamagata · 100 Onsen to Know Japan — No. 21

At five in the morning a market opens under the eaves of a snow-country spa village that has been in business since 807.

Ikaho Onsen

伊香保温泉

Gunma · 100 Onsen to Know Japan — No. 28

The spring runs beneath 365 stone steps and is tapped off to the inns tier by tier. A town built around the iron-browned 'golden water'.

Yōrō-keikoku Onsen

養老渓谷温泉

Chiba · 100 Onsen to Know Japan — No. 36

Dark-brown water in a Boso gorge where there are no volcanoes: the spring comes up cold, around 20°C, and is heated for the bath.

Shirahone Onsen

白骨温泉

Nagano · 100 Onsen to Know Japan — No. 50

Clear as it emerges, white once it meets the air. Shirahone's milkiness comes not just from sulfur but from calcium carbonate that solidifies, even building the 'funto-kyu' spring mounds.

Shinhotaka Onsen

新穂高温泉

Gifu · 100 Onsen to Know Japan — No. 54

Look up at 3,000-metre peaks from a riverside open-air bath, then ride a double-deck gondola from the same spot to 2,156 metres.

Hirayu Onsen

平湯温泉

Gifu · 100 Onsen to Know Japan — No. 55

Some forty sources pour out 8,600 litres a minute, and right by the bus terminal are a donation-only bath and a complex of sixteen open-air pools.

Yumura Onsen

湯村温泉

Hyogo · 100 Onsen to Know Japan — No. 64

Water at 98°C gushes from the rocks by the river at 470 litres a minute. People boil eggs in it, then soak their feet in the same water once it has cooled.

Totsukawa Onsen

十津川温泉

Nara · 100 Onsen to Know Japan — No. 69

Every bath in the village runs straight from the source, with no recirculation, no dilution and no chlorine. This is the heart of the mountain spa district that made that pledge in 2004.

Kawayu onsen

川湯温泉

Wakayama · 100 Onsen to Know Japan — No. 67

Dig into the riverbed and hot water wells up. In winter they dam the river itself and turn it into an open-air bath for a thousand.

Yunomine Onsen

湯の峰温泉

Wakayama · 100 Onsen to Know Japan — No. 66

You can bathe in a World Heritage site, thirty minutes at a time. The Tsuboyu, a pool hollowed from rock, is where Kumano pilgrims purified themselves.

Ryūjin Onsen

龍神温泉

Wakayama · 100 Onsen to Know Japan — No. 68

Between Koyasan and Kumano, on the clear upper Hidaka River, rises one of Japan's three 'beauty baths': a bicarbonate spring that leaves skin feeling silky.

Ureshino Onsen

嬉野温泉

Saga · 100 Onsen to Know Japan — No. 93

One of Japan's three great 'skin-beautifying baths', famous for its slippery bicarbonate water, and for tofu that turns silky and clouds the broth when simmered in it.

Nagayu Onsen

長湯温泉

Oita · 100 Onsen to Know Japan — No. 89

Sit in the 32 °C pool and within minutes your whole body is sheathed in silver bubbles: 1,380 mg of free carbon dioxide per kilogram, one of Japan's richest carbonated springs.

Kamata Onsen

蒲田温泉

Tokyo · 100 Onsen to Know Japan — No. 35

Water so black your hand disappears in it, in a neighbourhood bathhouse in Tokyo, for 600 yen.

Myōken Onsen

妙見温泉

Kagoshima · 100 Onsen to Know Japan — No. 98

A riverside toji village on the Amori River where every inn has its own spring and not a single bath is recirculated.

Aizankei Onsen

愛山渓温泉

Hokkaido

Ashibetsu Onsen

芦別温泉

Hokkaido