Mild and low in dissolved minerals. Usually clear and gentle on the skin, which is why these baths are often recommended for first-timers.
Salty water. The salt leaves a thin film on the skin, so you stay warm well after leaving the bath.
Clear water with a faintly bitter taste. Known for holding heat.
The classic rotten-egg smell and milky white water. It can tarnish silver jewellery, so take it off.
Planning a first soak? Read how an onsen stay works, and what to do if you have tattoos.