No country takes toilets quite so seriously as Japan.

Machines with heated seats, built-in bidets and a dynamic range of flushing options are almost ubiquitous in homes and public buildings.

A poem recently published by a stressed-out salary man captured their comforting appeal with haiku-like brevity. “The only warmth in my life is the toilet seat,” he mourned.

But lavatories here can do much more than keep you warm. One even sends a tiny electrical charge through the user’s buttocks to check their body-fat ratio.

The art of the toilet in Japan