A set of "transparent" toilets made from coloured "smart glass" that turns opaque when cubicles are occupied have opened in Tokyo.
The toilets, created by the Pritzker prize-winning architect Shigeru Ban and more than a dozen other leading designers, have been installed in five locations in the capital’s Shibuya neighbourhood.
They are part of the Tokyo Toilet Project, organised by the nonprofit Nippon Foundation.
The toilets have been compared to a "curious piece of playground equipment", although the foundation said there were several practical considerations that shaped the design.
Transparent toilets in Tokyo
"There are two concerns with public toilets, especially those located in parks," it said.
"The first is whether it is clean inside, and the second is that no one is secretly waiting inside."
The cubicles' glass outer walls turn opaque after the door is locked, allowing users to see inside before going to the toilet.
The foundation added: "At night they light up the parks like a beautiful lantern."
Japan's hi-tech toilets are renowned among tourists visiting the country, and the project plans to install toilets at 17 locations in Shibuya by next spring.
The toilets are made by Toto, and include washing and drying modes, seat warming and lids that open and close automatically.
They are also now being sold in China and several other countries, although the foundation noted that despite Japanese toilets' reputation for hygiene, many citizens still mistakenly view public facilities as "dark, dirty, smelly and scary".