Tomioka Silk Mill, Gunma | Japan is Nippon

Japan's first full-scale mechanised silk mill, built by the Meiji government in 1872. A World Heritage site in Tomioka, Gunma, with its brick buildings intact.

Arched entrance of the red-brick East Cocoon Warehouse at Tomioka Silk Mill — Photo: Hasec, Public domain, via Wikimedia Commons

Inside the silk-reeling mill at Tomioka, a long hall with rows of reeling machines under a truss roof — Photo: yellow bird woodstock from JAPAN, CC BY-SA 2.0, via Wikimedia Commons

The state-run factory that launched modern Japan

Tomioka Silk Mill, in the city of Tomioka, Gunma Prefecture, is a former silk reeling mill (a factory that makes raw silk thread from silkworm cocoons). It was built in 1872 (Meiji 5), not long after the end of the Edo period, by the new Meiji government as a model factory for the whole country. Raw silk was then one of Japan's key exports, and a major goal was to improve its quality.

Construction and technical guidance were led by the French engineer Paul Brunat. French machinery was adapted to Japan's humid climate, and the mill was worked by young women known as kojo (factory girls).

From 115 years of production to World Heritage

Starting out as a state-run factory, the mill later passed through the hands of Mitsui, Hara Gomei Kaisha and Katakura Silk (later Katakura Industries), and kept operating until it closed in 1987. That makes 115 years of making raw silk.

In 2014 it was added to UNESCO's World Heritage list as "Tomioka Silk Mill and Related Sites". In the same year, three of its buildings were designated National Treasures: the Silk Reeling Plant, the East Cocoon Warehouse and the West Cocoon Warehouse.

Touring the timber-framed brick buildings

Most of the buildings use mokkotsu renga-zo, a construction method borrowed from the West in which bricks are laid into a timber frame. The two cocoon warehouses, where cocoons were stored, are each more than 100m long.

The Silk Reeling Plant is where thread was drawn from the cocoons. The West Cocoon Warehouse finished six years of conservation work in 2020, and a gallery enclosed in steel and glass was created on its ground floor, where you can see the original walls and ceilings through the glass. Brunat House (the Director's House), where Brunat lived, also survives.

Guided tours and getting there

Guided tours are run on site by staff guides, who go into the history and the highlights of the buildings in detail. If it is your first visit, join one.

The nearest station is Joshu-Tomioka on the Joshin Electric Railway, about 1km from the mill, which you can walk. By car, it is about 10 minutes from the Tomioka interchange on the Joshin-etsu Expressway. Check opening hours and fees on the official website.

Tips

The site is large, and in some buildings you can go upstairs to the upper floor. Wear comfortable shoes.
Konnyaku Park, a theme park about konnyaku (a jelly-like food made from the konjac plant), is nearby, and by car you can visit both.
Special exhibitions are sometimes held. Check the news on the official website before you go.