A Taisho Substation Still at Work
The Hokkan Substation (北甘変電所) is a two-storey reinforced-concrete substation at Ichinomiya, Tomioka City, Gunma Prefecture, built in May 1919 as the Ichinomiya substation of the Seimo Electric company, and was registered as a Registered Tangible Cultural Property (structure) on September 19, 2003. It still works as a substation today (Tomioka City).
The Agency for Cultural Affairs records it as two storeys of reinforced concrete with a building area of 156 square metres; registration number 10-0101, owned by Tokyo Electric Power.
Powering the Tomioka Silk Mill
According to Tomioka City, from 1920 the substation supplied 8,422 households in Tomioka and 26 other towns and villages, and helped electrify the Tomioka Silk Mill. Tokyo Electric Power took it over in 1951, and it remains in service.
Inside, a room for repairing equipment, rails for trolleys carrying large machinery and a looping staircase survive. It is thought to be among the oldest reinforced-concrete buildings in Gunma Prefecture (Tomioka City).
Why It Was Registered
The Hokkan Substation was registered as a building that has become a model of design. The Agency for Cultural Affairs notes that, while functional in character, it achieves a varied and lively exterior.
What to Look For
Although the Hokkan Substation has a rigid frame, its walls are kept smooth with the columns hidden as far as possible, and the main areas of the rendered walls are finished in a German-style roughcast (Agency for Cultural Affairs).
Flat roofs set at different heights, many tall windows and small arched windows enliven the exterior (Agency for Cultural Affairs). Tomioka City points to its German-style stucco and its many tall and semicircular windows.
Visiting
The Hokkan Substation is a working substation, so the interior cannot be visited. It is at 422 Ichinomiya, Tomioka City, and the exterior can be seen from the surrounding streets (Tomioka City, Agency for Cultural Affairs).
Q&A
- When was the Hokkan Substation built?
- In May 1919, as the Ichinomiya substation of the Seimo Electric company (Tomioka City).
- How is the Hokkan Substation linked to the Tomioka Silk Mill?
- From 1920 it supplied power to the area and helped electrify the silk mill (Tomioka City).
- What does the Hokkan Substation look like?
- Smooth walls in German-style roughcast with many tall windows and small arched windows (Agency for Cultural Affairs).
- Is the Hokkan Substation still in use?
- Yes; Tokyo Electric Power took it over and it still operates (Tomioka City).
- When was the Hokkan Substation registered?
- On September 19, 2003.
Basic Information
| Name | Hokkan Substation (北甘変電所) |
|---|---|
| Location | 422 Ichinomiya, Tomioka City, Gunma Prefecture |
| Designation | Registered Tangible Cultural Property (Structure) |
| Year Designated | Registered 2003/9/19 (Heisei 15) |
| Quantity | 1 building |
| Dimensions | Reinforced concrete, 2 storeys, building area 156 square metres |
| Owner | Tokyo Electric Power |
| Public Access | Working substation; exterior only |
References
- Hokkan Substation (Database of National Cultural Properties, Agency for Cultural Affairs)
- https://kunishitei.bunka.go.jp/heritage/detail/101/00003517
- Registered Tangible Cultural Properties in Tomioka (Tomioka City)
- https://www.city.tomioka.lg.jp/www/contents/1000000000978/index.html
Last verified: 2026.10.10