What exactly is a 電気風呂 (denki furo)?

I’ve been to a number of sentou (public bath) and onsen (hot spring bath) all over Japan by now. In some of these (both sentou and onsen), I saw bathtubs labelled 電気風呂. I know enough Japanese kanji to read this as denki furo or electric bath but I do not know enough Japanese to understand what this is about (and arguably I might be reading it wrong and thus attempting to understand it wrong).

All the sources I could find by Googling are in Japanese and thus way above my level.

Surely a 電気風呂 isn’t a bath with an electric current going through it, but then what in the world is it?

Note: I have not been brave enough to just go inside and try it out.

japan hot-springs

Best Answer

The ???? passes a mild electric current so when you sit between the electrodes, you feel a slight tingly feeling. It’s usually one of the many different types of individual bath options (including jet baths) that a super bathhouse (??????) might have.

They warn people with weak hearts or pacemakers shouldn’t use the devices and I have to heartily (pun intended) agree.