Kubo Tsushima Architects gave a curved form to this public toilet in Japanese town of Nakanojo, to avoid creating spaces for dust to collect or spiders to lurk (+ slideshow).

The brief given to architects Hideaki Kubo and Yumi Tsushima was to design a bright and clean facility for both local residents and visitors to the Nakanojo Biennale of contemporary art, which takes place every other September.

"We were asked to create a toilet that could be a symbol of the town, and at the same time, a toilet that is not dismal like ordinary public toilets in Japan," they explained.

Their solution was to give the building as many curved surfaces as possible, rather than corners where grime can easily build up.

"We considered that the corner of the ordinary square toilet is a cause for the dismalness, by making a shadowed area for parasite-filled puddles, dust or spiders," said the pair.

The structure is divided up into two, forming one male and one female cubicle. Both are roughly semi-circular, and they sit alongside one another facing in different directions to create an S-shaped plan.

To further brighten the building, the architects chose a corrugated metal sheet with a white finish for both the interior and exterior walls. It conceals a simple timber framework.

Round skylights above the toilet basin and the sink bring light down into each space. There is also a urinal in the male cubicle.

"We were considering the maintenance of a public toilet, so instead of using wood to add cosiness, we removed the dismalness by designing contrast into the space," added Kubo and Tsushima.

The public toilet is located in a car park near a historic temple. From the road it is difficult to tell what it is, so a signage tower was installed outside.

It opened to the public earlier this year, in plenty of time for it to be used by visitors to the art biennale.

A public toilet was also built for another Japanese art fair – Yo Shimada of Tato Architects designed a facility for visitors to the 2013 edition of the Setouchi Triennale on Shodoshima Island.

But the coveted title of Japanese Toilet of the Year 2015 was awarded to an airport toilet by Klein Dytham Architecture that misleadingly appears to offer no privacy to its users.

Project credits:

Architectural design: Kubo Tsushima Architects – Hideaki Kubo, Yumi Tsushima
Structural design: Megumi Tamura
Construction: Kanna
Coordinator: Daiki Koga