Repairs to centuries-old temples in Japan are still carried out without using modern nails, screws or metal brackets. In Japan, master carpenters continue to follow an ancient woodworking technique that has been passed down through generations for more than 1,000 years.The method, called kigumi, involves precisely carving wooden joints so that they fit together like puzzle pieces. Beams, pillars and other parts of the structure are also shaped to lock into each other without the need for metal fasteners. This traditional technique is still used to restore some of Japan’s oldest temples and shrines. These structures have survived earthquakes, storms and changing climates for centuries.The artisans who carried out this work are known as miyaiku or temple carpenters.
Why does Japan avoid nails?
The continued use of wooden joints is not just about preserving tradition. This method also has practical benefits. Japan experiences sweltering heat, heavy rainfall, typhoons and frequent earthquakes. Metal nails rust over time as moisture penetrates the wood, weakening the joints and ultimately damaging the wood. However, with wood joints, wood expands in humid weather and contracts when the weather is dry. This does not put much pressure on the structure.It also helps buildings withstand earthquakes because unlike rigid metal connections, traditional wood joints move little during seismic activity. Flexibility absorbs and spreads vibrations throughout the structure, reducing the risk of serious damage during earthquakes. This is why many historical wooden temples have remained standing even after repeated earthquakes.
Kigumi, a method of joining wood without using nails or metal fittings
hand carved
Making these joints requires years of skill and precision. Instead of cutting identical pieces of wood, carefully study each piece of miyaiku wood. They examine the grain, natural bend, and strength of the wood before deciding where it should be used in the building.Different joints also serve different purposes. For example, tsuguite joins two pieces of wood to create long beams or pillars. Meanwhile, Japan’s Foreign Ministry reported that Shiguchi joins beams and pillars together at different angles to form the structure of the building.Each joint must also fit perfectly as even a small gap can weaken the structure. Most of these joints remain hidden inside the building, even though they are vital to its strength.
1,400 year old tradition
There are more than 150,000 temples and shrines in Japan, many of them built using traditional wooden construction methods. Some of the oldest temple carpenters in the country trace their origins to the construction of Shitenno-ji temple, which was founded in 593 AD.It takes years of apprenticeship to become a Miyadaiku. Carpenters pass on their knowledge to young craftsmen. They also teach them woodworking skills as well as understanding the natural properties of different types of wood.
Yusuhara Wooden Bridge Museum
This craft is also valued for its sustainable approach. Since wooden structures can often be taken apart, repaired and put back together without damaging the wood, individual components can be replaced without rebuilding the entire thing. This helps in extending the life of buildings and also reduces waste.