People just need to give a 'little touch' ('chotto' in Japanese).
The rest, nature will take care of.
The key is to spark a chain reaction where nature regenerate itself.
It all comes down to whether we can consistently nurture this process.
In the end, it’s just whether we do it, or not.
These are the words of Tomonori Yano, a Japanese landscape architect known for 'Daichi no Saisei®' (means 'regenerate the earth') and also he was featured in the documentary film 'Mori-bito' (A Doctor of the Earth).
There are various approaches and philosophies when it comes to protecting, restoring, and regenerating the natural environment, but our volunteer group focuses particularly on the "connection and circulation of water," aiming to regenerate natural ecosystems from water sources to rivers and all the way to the ocean by giving a little touch, 'chotto', to let nature regenerate by itself instead of the the mindset of "Humans should control" or "Human can control".
*Activity Location: Sekine River and Shonan Village Retention Basin in Miura Peninsula (Ōgusu Mountain Range – Sagami Bay watershed) in Kanagawa Prefecture, Japan.
*Registered as a 'Community Development Supporter' organization of Yokosuka City.
Since rivers, retention basins, and beaches are under the management of the city, we conduct our activities with the permission and cooperation of the authorities.
(This activity is organized by Mariko Miki, president of The Blue Inc.)
Background and Purpose of the Activities
Akiya district located on the western coast of the Miura Peninsula, stretches from Mount Ōgusu—the highest peak of the peninsula—down to Sagami Bay. Once a satoyama landscape, it was characterized by terraced fields and scattered rural settlements.
However, due to its convenient access from Tokyo and Yokohama and its scenic views of the sea and Mt. Fuji, the mountaintop areas with the best vistas were extensively reshaped and developed as golf courses during Japan’s period of rapid economic growth and the bubble economy.
When the bubble economy collapsed, plans for further golf course development were abandoned. The vast areas that had been cleared and leveled were instead transformed into “Shonan Village,” which now includes research institutions, corporate training facilities, and residential areas. Valleys that once carried streams collecting water from the watershed were filled in with soil excavated from the mountaintops and turned into wide roads.
In their place, artificial rivers and retention ponds were constructed, drastically altering the natural flow of water. It is said that when water flow is disrupted or stagnates, it has significant impacts on forests, soil, wildlife, rivers, and even the marine environment downstream. We believe that the desertification of the ocean is not caused only by rising water temperatures due to global warming, but also by the stagnation of natural water circulation—from surface to underground—that normally carries nutrients and oxygen from the land to the sea, nurturing seaweed and marine life.
Our Approach
Our approach, often referred to as “environmental civil engineering” or “ecological restoration techniques,” involves using organic materials such as branches, fallen leaves, natural stones, and charcoal to create opportunities for nature to restore its own balance. We have learned these methods from various landscape architects and specialists, and we carry out the work by considering and applying the best possible solutions for each specific time and place.
Percolation holes
By opening holes in dried, compacted soil or gleyed soil and filling them with branches, fallen leaves, biochar, and other organic materials, we create pathways for water and air to flow between the ground surface and the subsurface. This process promotes the growth of fine roots in plants and increases microbial activity, thereby enriching and stabilizing the soil and fostering greater diversity of trees, plants, and wildlife.
Air and rainwater channels
Brushwood check dam
We dig trenches on slopes—particularly at slope transition points around ponds or rivers—to improve ventilation and rainwater infiltration. These trenches are filled with biochar, branches, and fallen leaves, and we construct brushwood fences (shigara) using branches and bamboo to stabilize the soil.
Thicket clearing and pruning
Cut or trim grass as wind does
Instead of cutting at the base or ripping plants out by the roots, we cut high, at the natural sway point of the stems because when grass regenerates after being cut this way, it branches out more from the roots, and finer roots develop underground.
In areas around ponds and rivers that have become overgrown with thickets, we carry out thinning and pruning to improve airflow and light penetration. This encourages the growth of groundcover vegetation, which in turn helps stabilize the soil and promotes rainwater infiltration.
Other activities
River, pond, and beach clean
Collection of spring water from riverbeds and seabeds workshop
Collection of eDNA samples
（Instructor: Shogo Arai, Phycologist)
Workshop videos
2025年7月
Biodiversity specialist
Masako Sakata
2025年2月
Gardener, landscaper
Kazuyuki Hamada
2023年7月
Phycologist
Shogo Arai
2023年2月
Landscape engineer
Tomonori Yano
Work Schedule
Normally we work regularly a few times month, however during the intense summer heat, we can only work early in the morning with local regular members, so we’re pausing recruitment of new participants for now until fall.
If you’re interested in our activity, please feel free to send us an email at the address below.
email: chottojapan@icloud.com
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