The cedar-clad toilet is Kuma's contribution to the Nippon Foundation's Tokyo Toilet project, which has seen public toilets designed by Pritzker Architecture Prize winners Tadao Ando, Shigeru Ban and Fumihiko Maki in the city's Shibuya area.
Built to replace an existing brick toilet block within Nabeshima Shoto Park, the toilet was designed to integrate with the park's trees and lush greenery.
"There were many potential sites for this project, but I chose Nabeshima Shoto Park because it has the lushest greenery and I thought I would be able to dispel the conventional image of public toilets," explained Kuma.
Rather than creating a single block, Kuma broke down the facility into five huts that are connected by a stepped walkway that gives the project its name – A Walk in the Woods.
"In addition to the toilets, I designed the path that creates a line of flow, with the hope of offering a total experience that encompasses the surrounding environment as well as the structures."
The blocks are covered in cedar louvres, which are also used to create edges to the walkway and stairs.
Each one contains an individual toilet that was laid out to meet a particular user's needs.
"Until now, public toilets have all had exactly the same design, but for this project, I designed five small toilets including one that can be used by children and one where people attending Shibuya's many events can change clothes for the occasion," said Kuma.
"Unlike conventional public toilets, these are unique in that they can be used by a diverse range of people."
The toilet is the latest built as part of the Tokyo Toilet project, which aims to change people in Japan's perception of public toilets.
"We hope this will become a model for dispelling the conventional image of public toilets being dark, dirty, smelly, and scary, and that many people will use these toilets," said the Nippon Foundation's executive director Jumpei Sasakawa.
Previous facilities completed as part of the project include a circular toilet designed by Tadao Ando, a pair of transparent blocks designed by Shigeru Ban and a bright red triangular toilet created by Nao Tamura.
In total, 17 toilets are planned as part of the project.
Photography is by Satoshi Nagare, courtesy of The Nippon Foundation.