Public Lecture 1 – Regenerative Architecture

Regenerative Architecture: Innovating Urban Spaces for Greener Cities

“Compared to global standards, Tokyo’s green area is significantly smaller. While the global average for green spaces stands at around 46%, Tokyo’s green coverage is only about 21%. Given the city’s limited plot sizes, innovative architectural solutions are essential. What I aim to achieve is not architecture for the countryside, but architecture that thrives within the city,” said Mr. Kiyoaki Takeda, the founder of Kiyoaki Takeda Architects, as he opened his lecture on January 16^th, the first public lecture of this term.

In the lecture, he presented a compelling vision for "Regenerative Architecture" - an approach that seeks to integrate nature and biodiversity into urban environments. This philosophy stems from several key observations about our changing world and aims to address critical challenges facing cities and ecosystems, including the fact that artificial structures have surpassed natural ones globally since 2020, the rapid urbanization with 1.5 million people moving to cities annually, and the lack of sufficient green spaces in cities like Tokyo.

Mr. Takeda illustrated his philosophy through various innovative projects. Tsuruoka House is an award-winning project, that attempts to hold not only people but also other life forms. Mr. Takeda broke the usual boundary of “gardens” and “houses” by plotting the thick soil layers to support diverse plants and designing rainwater drainage through continuous vault slabs. The building becomes an integrated system that mimics civil engineering structures while coexisting with natural ecosystems. Despite the challenges of managing unpredictable natural forces like heavy rainfall, plant growth, and climate variability, innovative solutions such as layered soil structures and overflow pipes were implemented to stabilize and sustain the environment.

At Tsuruoka House, the vision is to foster a direct and harmonious relationship between humans and other living forms, where plants, birds, and insects gradually transform the space into a small forest. Over decades, the bio-mass of nature may surpass the human-made structure, symbolizing a balance between organisms and artifacts. The goal is not to solve global environmental issues but to create a life where coexistence and mutual appreciation between humans and nature can thrive.

The Seaside Kindergarten Project, whose varying diameters of the concrete elements are designed to support different floor levels. The project uses a triangular grid system of different-sized concrete "trees" to create a mixed natural and artificial environment that blurs the boundaries between indoor and outdoor spaces for the children.

Mr. Takeda found that bridges are often raised high to reduce noise for surrounding residential areas, leaving the space underneath unused. That’s how he came up with the idea of the Bridge Forest Project, which involves creating a small forest underneath an existing bridge structure. By modifying the existing bridge structure, his team was able to create a usable garden space for the community.

While Mr. Takeda’s approach is innovative, he acknowledged the challenges it faces, including maintenance, scalability, and lifecycle considerations.

During the Q&A session, the same concerns have been raised by the attendees, “Ensuring proper care for integrated natural elements over time is crucial,” Mr. Takeda stated, emphasizing the need for long-term thinking in architectural design. He believes that it is important to change people's awareness and engagement with the natural environment to create more sustainable and adaptable buildings.