Creating “the most hygiene public toilet” – Hi Toilet

30 November 2021

Creating “the most hygiene public toilet” – Hi Toilet

In August 2021, “Hi Toilet” designed by Kazoo Sato (Chief Creative Officer of TBWA\HAKUHODO) and the agency’s creative team Disruption Lab, has opened in Shibuya, Tokyo as the part of THE TOKYO TOILET Project by the Nippon Foundation.

Equipped with the originally developed voice recognition engine, Hi Toilet operates fully with a voice command – from opening and closing the door, flushing, and even playing music.

Until now public toilets have never had the greatest reputation especially when it comes to hygiene, which even got worse with the concern of infections through contact after the emergence of the COVID-19. Hi Toilet, designed to be a place where everyone can enjoy a clean, safe and entertaining time, suggests how public toilets can be re-imagined to fully serve people’s need for access to clean and safe toilets.

We spoke with Kazoo Sato, who led the production of this innovative toilet, about the inside story behind its creation and his thoughts on the “future of public toilets”

A way to the most hygiene public toilet

Creating “the most hygiene public toilet” – Hi Toilet

Q. Tell us how you joined THE TOKYO TOILET Project.

The Nippon Foundation who is leading the whole project had reached me and my team. Initially, I wondered why they would approach a creative director, not an architect. But as I was giving it more thoughts, I was fascinated by the fact that people from diverse backgrounds come together to solve the challenge of “creating public toilets that everyone can use enjoyably and safely” and come up with a variety of solutions, making full use of their individual strengths and specialty. I thought this diversity of the toilets being built represents the diversity of today’s society – and that’s why I decided to join the project.

Q. What was your goal in creating a “public toilet”?

Our goal was to create “the most hygiene public toilet” in the world. For this project, we conducted a survey on toilets usages in various countries and found out that many users avoid hand contact as much as possible – flushing weather by stepping on the lever, opening the door with toilet paper or their elbow, or closing the door with their hips. Even in Japan, public toilets are often perceived as the only place where public hygiene is lagging behind.

To realize a “toilet that doesn’t need to be touched with hands,” we had some ideas that were quite analog such as a toilet operated by stepping on the pedal or pushing buttons with elbows. But we had to consider the diversity of users. Using a physical method would exclude people with physical disabilities, such as those in wheelchairs. In order to make a clean restroom that is also as inclusive as possible, we got to the answer of “voice-controlled toilet”. Of course, for those who can’t speak the toilet can work with buttons.

Q. How’s the voice control work for Hi Toilet?

Creating “the most hygiene public toilet” – Hi Toilet

First, saying “Hi Toilet,” as you say “Hey Siri” or “Hey Google,” will activate the voice recognition system. And then say, for example, “open the door,” “flush the toilet,” and other commands and the toilet will operate as you ordered. Currently, the system supports Japanese and English.

The futuristic and as-hygiene-as-possible design

Q. Being “pure white” is very unique for a public restroom.

 At first, I was thinking of creating a pitch black toilet because a white toilet could get dirty easily, but as I hoped to make this toilet the symbol of cleanliness, I decided to go with pure white. I was concerned that it might be scribbled on. But I thought that a very clean and beautifully designed building actually makes people feel hard to stain. In fact, I have heard that the users and visitors of the other toilets built in various places for THE TOKYO TOILET PROJECT have been using the toilets as if they are enjoying “artworks” – and all are kept very clean.

Creating “the most hygiene public toilet” – Hi Toilet

Q. The dome shape also makes the toilet stand out – tell us the reason for the shape.

The architecture experts told me it is quite tough to create a perfectly spherical toilet, but I insisted on a circular design for several reasons.

First is that I wanted it to be a symbol of cleanliness, as the “World’s Most Hygiene Toilet,” and wanted to express the form of a single drop of clean water. I also thought that it would have more presence if it were a round object, while the surrounding buildings in the neighborhood are all square – so if you suddenly need to use the restroom, you can find it instantly. As it was placed in park where local people including families with children and the elderly enjoy using it, I thought the spherical design would give more fun and friendly vibe.

Another important point was designing the “air”. In addition to a system we have installed that ventilates the entire toilet space after each use, the round shape of the ceiling naturally makes it easier to circulate the air and prevents odor to linger. We were able to create optimal air circulation through a unique architectural design with the help of a research institute at the University of Tokyo, making sure the toilet stays as hygienic as possible all the time.

Q. It also shines with light-up at night.

Yes, it was to give it a bit of futuristic look and feel as I thought this voice-recognition toilet experience would be a very new experience for mankind. The reflection of lights makes the toilet look as if it is floating in the air. I hoped that the people who would see and use this space would also have a taste of the futuristic. 

Creating “the most hygiene public toilet” – Hi Toilet

“Hi Toilet, Play music”

Q. The Hi Toilet also has a music playlist – why did want to install a music system?

The playlist is also a part I paid huge attention to. When you say “Play Music”, you can choose from about 100 songs in 10 genres including hip-hop, rock, or classical music. Of course, it serves as an entertainment perspective so people can enjoy using the Hi Toilet but it also is meant to serve as a sound-covering function.

A lot of people flush the water to cover the sound while doing business in the toilet but that is a huge waste of water. I thought it would be great if music could be a substitute to hide the sound instead of flushing water.

By the way, there is also “thera-poo-tic music” for you. I read that excretion is apparently related to psychological state as well – so for example, when you are on a trip or nervous it is harder to excrete or causes diarrhea. So the mind control and relaxation have a great effect on excretion. 528 Hz is said to be a frequency that helps people to relax and stabilize minds, and we selected a music list in the frequency so that people can use it in a relaxed manner.

“Clean water and sanitation for all”

Q. How would you like to see public toilets evolve in the future?

The No.6 of UN SDGs is “clean water and sanitation for all.” It is of course great to see public toilets evolve in developed countries like Japan, where it is natural to have public toilets everywhere, but in some developing countries, there are still serious problems around public toilets. There are still many countries that do not have enough toilets from the first place or lack access to toilets that everyone can use safely in terms of hygiene and safety. I think that the world would be a happier place if we could break the convention of toilets and create toilets that are more sustainable, compact, and can be built anywhere.

Participating in this project made me realize that access to toilets is connected to basic human rights, and made me want to continue to come up with ideas that can contribute in any way possible to achieving the SDGs No.6.

Creating “the most hygiene public toilet” – Hi Toilet

Q. Tell us how you felt after working on this project.

THE TOKYO TOILET is a project to update and rethink the toilet itself. I hope that the Hi Toilet will not only be an example of a Hi-Tech toilet, but also a chance to change the perception that public toilets are scary or dirty – and also a motivation for many people to continue to update the toilets.
With the spread of the COVID-19, non-contact and public hygiene have become more important. I think this will be the century of fighting against or living with viruses – so I think that bringing “non-contact” into the “public” is a valuable innovation.

And, as I mentioned earlier, I would be happy if the concept of “if the first person uses something cleanly, the next person will keep it clean,” would spread more so everyone around the world would have access to clean toilets.
It was an honor to be part of this wonderful project!


This project by The Nippon Foundation aims for the realization of a society where all kinds of diversity are accepted, by building public toilets. With the full cooperation of Shibuya city, 17 toilets that are accessible for anyone regardless of gender, age, or disability will be created. Through the power of design and the creativity of 16 creators who support the objectives of this project, The Nippon Foundation is demonstrating what this new society can achieve. The toilets will be constructed by DAIWA HOUSE INDUSTRY CO., LTD., and TOTO LTD. will advise on toilet equipment and layout.

■Hi Toilet Video: Here

Stay tuned for the next episode!

Communication Team (