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Kominka – Japan’s Traditional Homes
The Essence of Kominka: What Makes It Unique?
In recent years, kominka have been gaining renewed attention—not only for their aesthetic appeal, but also for their alignment with sustainable living.While traditional features like thick beams and striking wooden pillars often catch the eye, what truly makes a kominka unique goes beyond appearances.This page offers a concise overview of what defines a kominka, including its structural characteristics, historical context, and cultural foundations.
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Definition of Kominka
There is no strict legal definition of kominka, such as one defined by Japan’s Building Standards Act. However, the term generally refers to houses built before 1950—prior to the enactment of that law—characterized by features such as traditional construction methods, natural materials, and strong regional adaptation.
While some people refer to any house over 50 years old as a kominka, few would consider a typical home built in 1975 to fall into this category today (2025), despite its age.
Just as a townhouse (machiya) in the Kansai region is vastly different from a farmhouse in Japan’s snowy regions, kominka vary significantly across the country due to Japan’s diverse climates and cultural zones.
These differences are part of what make the definition of kominka somewhat ambiguous—but also what make them so fascinating.
Each of these traditional homes reflects the cultural practices, architectural ingenuity, and environmental adaptation that people in each region developed over generations.
In many cases, kominka still embody the wisdom of past lifestyles and the craftsmanship that made these homes truly suited to their environment.
Understanding these design choices can also offer valuable hints when considering repairs or reuse.
The unique appeal of kominka lies in their cultural significance, regional identity, and historical layers—all of which come together to form a kind of living “story” not found in modern houses.
This page offers a concise introduction to the cultural background, design principles, construction materials, and recent trends surrounding kominka in Japan.
Features of Kominka: Summer Comfort, Open Layouts, and Traditional Values
One of the most distinctive features of kominka is how they were designed to make summers more comfortable.
For example, deep eaves were used to block direct sunlight, and earthen walls cooled during the night helped suppress indoor heat during the day.
Materials such as wood, earth walls, and natural tatami mats all have moisture-regulating properties that help ease Japan’s hot, humid summers.
It was also common to switch regular sliding screens to summer sliding screens designed to promote airflow. Combined with open floor plans, this created excellent ventilation and minimized stagnant air.
In addition, trees and ponds around the home helped lower the surrounding ground temperature.
Thatched roofs and white plaster walls also served as passive cooling features.
This type of design stands in stark contrast to modern homes, which emphasize airtight, insulated construction.
Kominka are built around openness, allowing heat to escape through natural airflow.
The open layout of kominka wasn’t only meant to adjust to the summer climate.It also reflected the values of the time. it also reflected the values of the time.
One notable feature is the absence of individual rooms for each person.
The layout was shaped by the concept of hare (special occasions) and ke (everyday life), as well as a desire to support shared living and communication among family members and the local community.
In contrast, modern homes tend to have clear boundaries between indoor and outdoor spaces, designed to block out external elements.
Kominka, however, have soft boundaries with the outside world and are characterized by their openness.
Even while indoors, one can feel the changing of the seasons—a home designed for living in harmony with nature.
Building Homes Rooted in Regional Culture: “Yui” and “Hare-Ke”
The history of Japanese wooden architecture is extremely old — the world’s oldest wooden building, Hōryū-ji Temple, have been built about 1,300 years ago.
Even today, traditional kominka built with age-old construction techniques remain throughout Japan. As of 2025, there are approximately 1.01 million such buildings.
These structures serve as valuable cultural assets that communicate the way of life and regional culture of the past.
In earlier times, home construction was called fushin, and it was carried out with the mutual support of local residents.
This system of mutual aid was known as Yui (結), through which labor and materials were shared and homes were built by entire communities.
This traditional building culture was more than just technique or structure — it represented a way of life rooted in local society.
The layout of traditional kominka is fundamentally based on this distinction.
Hare spaces are public areas, typically facing the garden. These include the entrance, the earthen floor (doma), and the formal guest room (omote-zashiki).
Ke spaces are private and functional, including the kitchen, inner rooms (oku-zashiki), and the Buddhist altar room (butsuma), which are used for daily routines.
This distinction is so fundamental that even the smallest kominka—some with only two or four rooms—were designed to clearly separate Hare and Ke spaces.
The way these homes were organized reflects more than just practical needs; it embodies the values, customs, and lifestyle of the time.
Understanding this concept adds depth to how we view and interpret these traditional houses—each layout can be seen as a cultural artifact in itself.
Materials and Wisdom Adapted to the Local Environment
Kominka were not simply homes built with whatever materials were locally available.
They were constructed with a deep understanding of local climate, geography, and wood characteristics — based on the principle of using the right material in the right place.
For example, the north side of a house might use wood from trees that grew on the north side of a mountain.
Each wood type was selected and used with consideration of its unique properties — curvature, twisting, strength, and how it changes over time.
Hardwood was used for flooring, sturdy wood for pillars, and resiny woods were avoided in visible indoor areas.
In wealthier homes, more labor and effort were invested. In large farmer residences, it is common to see fine beams, columns, and high-quality materials.
Kominka are not only locally sourced, sustainable houses — they also embody Japanese history, regional culture, and the wisdom of past generations.
Naturally Dried Wood and Remarkable Durability
Freshly cut wood cannot be used for construction as-is; it must first be dried.
In modern construction, kiln drying is the standard. Wood is dried at low, medium, or high temperatures depending on its intended use.
Because it allows precise control of moisture content, easier dimensioning, and quick turnaround, it became widespread during Japan’s post-war economic boom.
In contrast, kominka used naturally dried wood.
Depending on the wood’s properties and purpose, it was dried over several years when necessary.
Natural drying enhances the wood’s beauty, aroma, and strength. Because it does not involve machinery, it imposes minimal environmental impact and is considered a sustainable method.
However, natural drying also has drawbacks: controlling moisture is more difficult, there are risks of insect damage and mold, and above all, the process is time-consuming.
These disadvantages may make it incompatible with modern efficiency-driven demands.
Kiln drying forces moisture out in a short period, stripping the wood of its natural oils. This makes it prone to internal cracking and significantly inferior in scent, luster, humidity control, and durability compared to naturally dried wood.
In one study examining the impact on the human prefrontal cortex, kiln-dried wood showed no effect, while naturally dried wood produced a calming effect similar to being in nature.
This is why kiln-dried wood is sometimes said to “kill the wood,” whereas natural drying is described as a method that “keeps the wood alive.”
Wood’s inherent durability is remarkable.
A study on Japanese cypress (hinoki) showed that its strength peaks 100 years after felling and remains stable for several hundred more years.
It begins to decline after 700 to 800 years, proving that wood can endure for multiple generations.
Recently, such wood has been re-evaluated for its superior qualities and environmental benefits.
When thinking about kominka and their restoration, it may be equally important to consider the wood itself.
Preserving Traditional Skills and Knowledge
One of the greatest values of kominka lies in their traditional construction methods — techniques that can no longer be used under current Japanese building codes.
As prefabrication (pre-cut) became the norm and the number of carpenters decreased, artisans skilled in traditional hand-cut joinery also dwindled significantly.
In recent years, however, interest in kominka has grown, and more people are becoming interested in learning traditional methods through tours, workshops, and educational events.
Specialist organizations have also developed inspection systems and seismic evaluation criteria tailored to traditional houses.
This has led to changes — even traditionally built homes can now qualify for housing loans if they meet certain standards.
By conducting appropriate inspections to assess the condition of the home, hiring experienced craftsmen, and receiving proper guidance for DIY repairs, the opportunities to preserve and revitalize kominka under the right conditions are increasing.