Tomioka Silk Mill and Related Sites

UNESCO World Heritage

Outside of Tomioka Sill Mill (UNESCO world heritage)

Tomioka's Silk - an essencial contribution to Japan's modernization

The Tomioka Silk Mill and its related sites are registered as UNESCO World Heritage sites. They offer visitors a unique view into how Japan modernized itself and rose to one of the superpowers in the early 20th century. These world heritage sights are nestled in the heart of Japan, 2 hours from Tokyo and are a must-visit for travelers interested in uncovering Japan’s modern history.

Why was Silk important ? -The Story -

Favorable Climate:

Mulberry trees are need to cultivate silkworms and Japan has an ideal climate to grow them. Around 2,000 years ago, sericulture (silk farming) was first brought in from China and developed throughout Japan during the Nara period (710-794).

During the Edo period (1603-1867), the Edo shogunate encouraged sericultural activities, and various feudal clans promoted sericulture to expand their trade.

At the end of the Edo period, sericulture became very popular, and the invention of revolutionary sericultural techniques led to the production of high-quality raw silk.

The European Silkworm Disease
(The Shift in Global Silk Production):

In 1865, a disease hit the European silk industry. It almost wiped out France’s silk worms and threatened the entire region’s economy. The disease even spread further to other silk-producing countries as people weren’t able find a way to stop it. This led to an overwhelming shortage of raw silk for the use in silk fabrics in Europe.

In 1859, a few years prior to this happening, Japan had just opened its borders to the outside world. Once Yokohama and other ports opened their doors to trade with the Western countries, the British, French, Italian, and other merchants competed for Japanese raw silk due to the shortage in Europe.

19 century France

Japan's Advantage and Market Expansion:

Japanese raw silk sold exceptionally well, but the quality produced by in-house handcraft workers was inconsistent, and its reputation gradually declined. However, European countries needed to import raw silk urgently. So they sent official envoys  accompanied by a raw silk specialist to inspect the state of silk production in the countryside.  They came to a conclusion that adopting the European technology of machine-made silk would help quality and efficiency.

Meanwhile, the Japanese authorities, who had just established a new government (the Meiji era 1868-1912), were looking for a way to move forward their “wealthy nation and strong army (富国強兵)” program. Selling a lot of raw silk was one way to earn foreign currency and fund this idea. This meant it was crucial to introduce the efficient European silk manufacturing technology and improve quality to build stable production and sell it at a higher price.

The Meiji government went to Paul Brunat, a French silk inspection engineer and asked if he could help build a government-run silk factory. After inspecting different locations, Brunat selected Tomioka as the location. Less than two years later, a huge red-brick factory with two cocoon warehouses, the likes of which no one had ever seen before was completed.

The Tomioka Silk Mill became a symbol of Japan’s industrial revolution and was completed in the same year the first railway opened in Japan. It stayed operational for 115 years and was a model for other factories that opened later. Due to the expansion of silk mills which were based on the Tomioka model, Japan became the ‘number one’ producer of raw silk by the early 20th century producing as much as 60 percent of the world’s supply.

Outside Tomioka City Silk Factory
Inside Tomioka Sill Mill in Tomioka city (UNESCO world heritage)

Tomioka's UNESCO World Heritage sights

Tomioka Silk Mill

Tomioka Silk Mill (富岡製糸場) was built in 1872 to increase the production and quality of Japanese raw silk and was operational for 115 years before it closed in 1987.

Today it is a museum that houses a Silk-reeling plant, two massive Cocoon Warehouses, an Iron Water Tank (one of the oldest iron structure made in Japan) and the house that Paul Brunat lived in.

To visit see map here (Map)
*The Iron tank is not open to the public.

Tajima Yahei Sericulture Farm

Tajima Yahei Sericulture Farm (田島弥平旧宅) is a farmhouse built by Tajima Yahei in 1863. Yahei studied sericulture and established 'Seiryo-iku', a method of creating a well-ventilated environment for silkworms. His farmhouse's design was based on his theory, which had an innovative roof structure. His success changed the design of Japanese silkworm farmhouses.

To visit see map here (Map)

(Photo: Gunma pref)

Takayama-sha Sericulture School

Takayama-sha Sericulture School (高山社跡) is where Chogoro Takayama created the 'Seion-iku method', a method of sericulture he taught to students from all around Japan as well as China, Taiwan, and Korea.

'Seion-iku' became a standard of modern sericulture in Japan and helped Tomioka Silk Mill test silkworms and provide instructions to farmers.

To visit see map here (Map)

(Photo: Gunma pref)

Arafune Cold Storage

Using the cool air flow that flows though the gaps in the rocks of the mountainside, Arafune Cold Storage (荒船風穴) was built in 1905 as a natural refrigerator to keep the silkworm eggs from hatching.

Just by using the natural cool breeze, the rooms were kept at 2 degrees Celsius even during the summer. This made it possible to control silkworms from hatching making it possible to supply silk worms to the silk factories all-year-round and boost production.

The foundation of the buildings that stood there remains today.

To visit see map here (Map)

World Heritage Visitor Center

Sekaito (セカイト) is where you can learn about the four UNESCO registered sites and the rich history of silk production and its connection with the global silk trade. Learn from the interactive displays, maps, vintage photographs, and videos showcasing the history of sericulture, providing insights into the lives of people involved in silk production and how silk production spread around the world.

To visit see map here (Map)
(Photo: Gunma pref)

Famous Silk Kimono destinations nearby

Yuki & Oyama (Yuki Tsumugi)

Yuki city  and Oyama city are home to ‘Yuki Tsumui’ a UNESCO Intangible cultural heritage.

The ‘Yuki Tsumugi’ fabric goes through a meticulous process of extracting silk floss from silkworm cocoons and spinning it by hand into yarn. This fabric bears the most beautiful, dyed patterns created by skilled artisans using the kasuri ikat technique before weaving it on a Jibata (地機) loom. This fabric is a testament to the hard work, dedication,

Oyama city UNESCO Yuki Tsumugi yarn


Kiru City has a strong reputation as the hub of textile manufacturing in Japan. With over 1,200 years of experience, the locals take pride in showcasing their expertise in silk fabric production and offer workshops using their traditional weaving machines. In addition, there are places where you can rent kimono to wear for the day or buy Kimono fabric at a reasonable price. Visitors can also rent bicycles at Kiryu Station to move around the city and explore all that Kiryu has to offer. (See Kiryu’s city page here)

5 interesting facts about Silk

Silkworm making a cocoon
Weaving silk with jiba
Silk Kimono

1. When did silkworm cultivation start?

Silk production, known as sericulture, has a long history dating back to 2640 B.C which means it has been around for about 5,000 years. Legend has it that a Chinese princess was the first to real a cocoon of silk which dropped into her cup of tea!

2. How long is a thread of silk?

A single silkworm cocoon is made of one unbroken thread about 900 meters (3000 feet) long. To produce half a kilo of silk, it takes approximately 3,000 cocoons.

3. How is Silk made from a silkworm

After silkworm eggs hatch, they are fed mulberry leaves and grow rapidly. Once the silkworms have reached their full size, they enter the spinning stage and construct a protective cocoon around themselves.

The cocoons are then placed in hot water or steamed to soften the silk fibers and dissolve the sericin, a natural gum that helps hold the cocoon together. Finally, the softened silk fibers are carefully unwound from the cocoons using a process called reeling.

The raw silk thread is finally ready to be dyed, twisted, and spun into various types of silk yarn suitable for different products.

4. Is silk a natural insulator?

Silk acts as a natural insulator, which means it traps warmth when it’s cold outside, making you feel cozy. At the same time, it lets heat escape when it’s hot. It’s like having a built-in thermostat. In addition it doesn’t trap moisture, keeping you feeling dry and comfortable. Its shiny appearance and strong fibers make it a durable and long-lasting.

5. How long does it take for a silkworm to complete its cocoon?

To spin its silk cocoon, a silkworm rotates its body in a figure-8 movement and continues this for about 300,000 times! It takes a silkworm between 3 to 8 days to finish.

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