TOTO's 1988 Otohime turns toilet-noise shame into a water-saving sound button

In 1988 TOTO put a small box on the wall of Japanese public restrooms. Called Otohime, or 'Sound Princess', it plays the sound of running water for about 25 seconds when pressed, so a visitor who wants to hide toilet noise no longer needs to flush twice. The name came from the first female developer on the project, who combined the word for 'sound' with the Japanese fairy-tale princess Otohime and the culture of modesty it stands for.

The idea was born from a resource problem. In the 1980s, urban Japan had chronic water shortages, and TOTO's research noticed that many women flushed the toilet once before using it and again afterwards to mask any sound — water wasted purely on embarrassment. The device turned that wasteful habit into a deliberate product: press the button, hear the flush, save the water. Kids Web Japan reports TOTO estimated savings of up to 20 liters per toilet visit; an office with 400 female workers could save over 10 million liters a year, about 7.74 million yen.

Otohime stayed in production for decades, adapting rather than disappearing. In 2011 TOTO changed the sound source from a flush-like noise to a gentle stream with birds, to answer new needs such as masking the sound of disposing of sanitary products and creating a relaxing atmosphere. An NPR report from 2017 describes the device as coming standard with almost every Japanese toilet, and TOTO's own site says that even today about one in four people still flush while using the toilet — the button exists precisely because that habit never went away.