People often use the word onsen to describe any Japanese bath. Strictly speaking, that's not quite right.

An onsen is defined by its water.

Japan sits on one of the world's most active volcanic zones, giving the country more than 27,000 natural hot spring sources. When water rises naturally from underground at the required temperature and contains naturally occurring minerals, it can be recognised as an onsen.

That mineral water is what makes an onsen different from a sentō, which usually uses heated tap water instead.

No two onsen are exactly alike. Some waters are rich in sulphur and carry the unmistakable scent of volcanic springs. Others are crystal clear, silky to the touch, or coloured brown by minerals absorbed deep underground. Many people choose an onsen as much for the character of the water as they do for the setting.

Whether you're soaking beside a mountain stream, overlooking the sea or relaxing in the middle of a city, the ritual remains much the same. You wash before entering, slip quietly into the water, and simply allow the hot spring to do what it has done for generations.

In Japan, an onsen isn't simply a place to bathe. It's a chance to connect with the landscape itself.

Experience Japan through its waters.

The Yū Journal explores the landscapes, rituals and traditions behind Japanese bathing. Join our mailing list and follow the journey as Yū Bathhouse takes shape.