Sumu Yakushima Residència

Press Kit

Unique Properties

Yakushima Island is a natural paradise in southern Japan where abundant rainfall onto 2,000-meter peaks nurtures dense forests home to millennium-old Japanese cedar.
This innovative housing co-op applies Regenerative architecture to reconceptualize the relationship between human habitation and this nature. The name Sumu means both to live and to become clear, expressing its core concept of living in a way that positively impacts the landscape.

Dimensions & Packaging

The building area: 162m2.

Tags

Regenerative, Sustainable, Nature positive, Environmental

Production Technology

Burned wood is placed under the foundations, and carbonized surfaces promote the growth of mycelium, joining the buildings to the soil network. This promotes a symbiotic effect whereby tree roots grow under the buildings and support the soil.
Sumu comprises several separate buildings to enable a layout that respects the original natural landscape. The buildings protect the tree roots and reduce the impact of the wind, while stones supply minerals to the surrounding soil and foster tree growth. Tree roots passing under the buildings support the soil, an act of symbiosis between nature and architecture.

The buildings are raised, dispersing wind flowing between mountain and sea without blocking it. This allows the forest to breathe, promoting healthy air and water circulation. Despite the humid climate, this ventilation prevents moisture accumulation that may damage the buildings.

The off-grid kitchen made with local cedar features a solar-powered radiant heat cooker, while water is drawn from the river basin, then cleaned and returned to nature after use.
Lights made from local soil fill rooms with light embodying the color of the surrounding earth, and plaster made from a hemp charcoal/EM bacteria mixture provides healthy, comfortable spaces by preventing putrefactive bacteria.

Design Challenge

While the global pursuit of sustainability is highly commendable, in architecture it is generally understood as an effort to reduce negative impacts rather than to generate positive ones. This assumption stems from viewing architecture as an isolated object. In reality, every building site already contains an existing ecosystem. The project sought ways for architecture to connect with and contribute to the regeneration of that ecosystem.

It was an unprecedented challenge, and until measurable results began to appear, the process relied on careful observation, research, and repeated trial and error. In Japan, very few practitioners have direct experience with this construction method. Drawing from their knowledge, the team gradually developed its own methodology. Communicating appropriate instructions to local craftspeople was also a significant task.

After completion, however, positive outcomes began to emerge, as described earlier, and verification of the method is still ongoing.

Research

Regenerative architecture is a method of building that works with soil microorganisms, supporting healthier conditions for surrounding plant life. It applies, in a contemporary way, traditional Japanese civil engineering knowledge that has largely been forgotten.

To examine the effectiveness of this approach, three methods were used.

First, the construction site itself was deliberately selected. The building was placed on the most degraded and depleted area within the property. The land was overgrown with weeds to the point that it was difficult to enter, mosquitoes were abundant, and the trees were weak, with thinning trunks and falling leaves. The structure was positioned in close relationship to these struggling trees. After construction, the trees showed clear signs of recovery and renewed vitality.

Second, in order to visualize the underground mycelial network, experiments were conducted that identified the presence of electrical activity within the soil. Evidence indicated that trees on either side of the building were connected through electrical signals transmitted underground.

Third, microbial diversity was analyzed. Soil samples were collected both from the surrounding forest—where no intervention had taken place—and from the center of the Sumu site. The results showed that microbial diversity at Sumu was nearly three times greater than that of the surrounding untreated forest.

These findings suggest that human involvement can contribute to ecological enrichment. Beyond architectural technique, this approach may also influence how humanity understands its role within the Earth’s living systems.

Inspiration

Sumu is a place for tending to nature while reflecting on values.
It applies Regenerative architecture, a new approach developed by the designers that combines traditional Japanese civil engineering with contemporary technology.
Going beyond simply preserving nature, key considerations in the design are:
1. Designing the underground environment
2. Orientating buildings based on in-depth understanding of water and air flows
3. Creating an ongoing connection with nature through architecture

Project Duration

Duration：
The project began in 2020, with the first phase of construction expected to be completed in 2022. Since then, the project has continued to expand its scope of activities, including the expansion of the deck, regenerative activities, and soft aspects such as education.
Location: Yakushima island, Kagoshima, Japan

Operation Flow

True to its concept of making a positive impact by living among nature, Sumu residents adopt a “regenerative lifestyle” that enhances the environment through everyday activities, from collecting driftwood for use as firewood to clearing grass to allow cool air to flow through in a way that benefits the landscape.
Sumu's design changes our relationship with nature. It enables residents to discover new possibilities for interacting with nature and adapt the way they think and act, building relationships with nature that transcend generations. Its unique approach has the potential to accelerate environmental initiatives if more widely applied.

Image Credits

Photo: Rui Nishi