Sulfate spring

Kawayu Onsen

川湯温泉

Hokkaido · 100 Onsen to Know Japan — No. 2

Water acidic enough to corrode a nail runs as an open river through the middle of town.

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.

Asamushi Onsen

浅虫温泉

Aomori · 100 Onsen to Know Japan — No. 11

Twenty-five minutes by local train from Aomori, you step off the platform straight into a hot-spring town with Mutsu Bay at your feet.

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.

Sukawa Onsen

須川温泉

Iwate · 100 Onsen to Know Japan — No. 16

At 1,126 metres on the flank of Mt Kurikoma, 6,000 litres a minute of strongly acidic water pour into Dainichi-yu, an open-air bath big enough for fifty.

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.

Zaō Onsen

蔵王温泉

Yamagata · 100 Onsen to Know Japan — No. 19

Strongly acidic sulfur water at pH 1.25–1.6. Three communal baths for 300 yen each, a vast riverside open-air bath, and in winter the snow monsters of Zao.

Futamata Onsen

二岐温泉

Fukushima · 100 Onsen to Know Japan — No. 24

The water rises straight out of the rock beneath your feet, in a riverside valley whose spring was reputedly found in 969.

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'.

Kusatsu Onsen

草津温泉

Gunma · 100 Onsen to Know Japan — No. 25

Thirty-two thousand litres a minute of pH 2.1 acid water rise in the middle of town and cool as they run down wooden channels.

Shima Onsen

四万温泉

Gunma · 100 Onsen to Know Japan — No. 26

A wooden bath-inn built in 1691 still takes guests, and you can drink the water at fountains by the river. A clear spring named for 'curing forty thousand ills'.

Hōshi Onsen

法師温泉

Gunma · 100 Onsen to Know Japan — No. 27

In a bathhouse of 1895 with arched windows, the water rises between pebbles on the floor. One inn, one bath, and the old etiquette of mixed bathing still in use.

Yugawara Onsen

湯河原温泉

Kanagawa · 100 Onsen to Know Japan — No. 34

A spring sung about in the eighth-century Manyoshu still rises in the Fujiki valley, sixty minutes by train from Yokohama.

Yamanaka Onsen

山中温泉

Ishikawa · 100 Onsen to Know Japan — No. 41

In the gorge town where Basho praised a scent of hot water that needed no chrysanthemums, the Kiku-no-yu public bath still sits at the town's navel.

Shibu Onsen

渋温泉

Nagano · 100 Onsen to Know Japan — No. 48

Borrow a key from your inn, take a towel, walk the stone-paved street and stamp it at nine public baths in turn. In Shibu Onsen, staying the night is the ticket to the baths.

Jigokudani Onsen

地獄谷温泉

Nagano · 100 Onsen to Know Japan — No. 49

In 1961 a young monkey followed a dropped apple into the inn's open-air bath, the first monkey anywhere known to bathe in a hot spring. There is still only one inn.

Atami Onsen

熱海温泉

Shizuoka · 100 Onsen to Know Japan — No. 56

More than 500 sources give about 20,000 litres a minute at an average of 63 °C; from the foot bath outside the station to the geyser up the hill, the whole town is built on hot water.

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.

Iwai Onsen

岩井温泉

Tottori · 100 Onsen to Know Japan — No. 75

A towel on your head, a ladle in hand, a song on your lips as you pour water over yourself: Inaba's oldest spring keeps a strange ritual for staying in the bath longer.

Tamatsukuri Onsen

玉造温泉

Shimane · 100 Onsen to Know Japan — No. 76

'Bathe once and your features turn fair; bathe twice and every ailment is gone.' A riverside town that the Izumo Fudoki called 'the hot water of the gods' some 1,300 years ago.

Ibusuki Onsen

指宿温泉

Kagoshima · 100 Onsen to Know Japan — No. 97

In Ibusuki you lie down in your yukata on the beach and are buried in sand warmed by hot spring water rising from below.

Aizankei Onsen

愛山渓温泉

Hokkaido

Asahi Onsen

朝日温泉

Hokkaido