In appearance, the Washlet is nothing more than a hi-tech lavatory. The secret is beneath the rim where, as well as a heating element in the seat, it contains a small nozzle.
By operating an instrument panel at the side, it is possible to project between the cheeks a jet of water in a range of temperatures and pressures. Another button triggers an air jet which blow-dries the thoroughly cleansed bottom. Just as offices have become "paperless", so too can lavatories.
It was launched in 1980 with the slogan: "Your bottom will like it after three tries. Don't let people say behind your back that you have a dirty bottom." The Washlet has quickly become a Japanese institution: the original manufacturer, Toto, has sold 10 million units, and bottom-cleansing loos sell 2.2 million a year at a starting price of 75,000 yen (pounds 360).
Outside Asia, however, they have failed to cause a splash. The Swiss top the league, with 2,500 purchases a year, but Americans buy only 5,000, and elsewhere numbers are insignificant.
In response to this humiliation, Toto is launching an aggressive marketing campaign called "Using Is Believing", and is planning to install. the gadgets in lavatories at 600 bathroom centres outside Japan "so people can actually try them out and see for themselves how nifty they really are".