The Biggest Building on the Estate
The Former Sato Family Residence (Fujimoto) Silkworm Room No. 2 is a two-story, earth-walled rearing house built in 1890 on the estate of a silkworm-egg producer in Kamishiojiri, Ueda, Nagano Prefecture, and it was registered as a Registered Tangible Cultural Property on August 15, 2024. In Japanese it is 旧佐藤家住宅（藤本）二号蚕室, Kyū Satō-ke Jūtaku (Fujimoto) Nigō Sanshitsu.
With a footprint of 106 square meters, it is far larger than Silkworm Room No. 1 (63 square meters), built the same year, and the largest of the six registered buildings. It stands toward the south of the lot, facing south, with its ridge running east to west.
The Sato family's head house, trading as Fujimoto, produced silkworm eggs for sale. Raising healthy parent moths meant keeping temperature and humidity under tight control, and Silkworm Room No. 2 was designed to do much of that work itself.
State-of-the-Art in 1890
The building was registered for its contribution to the historic landscape of the country. The Agency for Cultural Affairs notes that its karo fire furnaces, slatted ceiling, and adjustable vents survive, preserving a clear picture of the egg trade as it was practiced.
The furnace has a pedigree. According to the local paper Toshin Journal, it was modeled on a heating furnace described in a book issued in 1887 by the Ministry of Agriculture and Commerce, and it was built to burn slowly for long hours inside the building. In other words, a private egg producer was putting the government's latest recommendations into practice within a few years of their publication.
The same report says the names of Fujimoto Zen'emon and the carpenters are written on a beam upstairs. At one point the city of Ueda even discussed moving the building elsewhere to preserve it, though the plan never went ahead.
What to Look For
Start with the roof. A koshiyane, a raised secondary roof, runs the entire length of the ridge, leaving a gap beneath it through which hot, humid air could escape. A vent that long says a great deal about how seriously the builders took ventilation. Lean-to roofs, or Geya, are attached on the north and south.
The walls are finished in white Shikkui plaster, and the eaves are plastered over in the shape of the Taruki rafters, so the rhythm of the rafters shows through as white ribs. Windows and vents open on the north and south walls.
Inside, the slatted ceiling is the thing to notice: thin strips laid with gaps between them so that warmed air could rise from the room below. The Agency for Cultural Affairs database includes a photograph of it, along with an exterior view from the south.
Visiting Silkworm Room No. 2
The Former Sato Family Residence (Fujimoto) Silkworm Room No. 2 stands on private land owned by Fujimoto Kogyo Co., Ltd. and is not open to the public. Requests to visit must go to the owner, and we found no published guidance on photography.
To understand how furnaces and slatted ceilings were used, the nearby Fujimoto Sericulture History Museum holds tools and records from the family's egg business. Visits are arranged in advance through Fujimoto Kogyo.
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Q&A
- Can you visit the Former Sato Family Residence (Fujimoto) Silkworm Room No. 2?
- No. It stands on private property and is not open to the public. Anyone hoping to see it should contact the owner, Fujimoto Kogyo Co., Ltd.
- When was the Former Sato Family Residence (Fujimoto) Silkworm Room No. 2 built?
- It was built in 1890 and registered as a Registered Tangible Cultural Property on August 15, 2024.
- What is special about the furnace in the Former Sato Family Residence (Fujimoto) Silkworm Room No. 2?
- It is reported to follow a design published by the Ministry of Agriculture and Commerce in 1887 and was built to burn slowly for long periods, which made it advanced equipment for its day.
- What is the small roof on top of the Former Sato Family Residence (Fujimoto) Silkworm Room No. 2?
- It is a koshiyane, a raised ventilation roof. It runs the full length of the ridge and let hot, humid air escape from the rooms below.
- How big is the Former Sato Family Residence (Fujimoto) Silkworm Room No. 2?
- It is a two-story earth-walled building with a footprint of 106 square meters, the largest of the six registered buildings on the estate.
Basic Information
| Name | Former Sato Family Residence (Fujimoto) Silkworm Room No. 2 |
|---|---|
| Location | 88 Minamigawa, Kamishiojiri, Ueda, Nagano Prefecture |
| Designation | Registered Tangible Cultural Property (Building) |
| Year Designated | Registered 2024/8/15 (Reiwa 6) |
| Quantity | 1 building |
| Dimensions | Dozo-zukuri, 2 stories, tiled roof, building area 106 square meters |
| Owner | Fujimoto Kogyo Co., Ltd. |
| Public Access | Not open to the public (private property) |
References
- Database of National Cultural Properties (Agency for Cultural Affairs): Former Sato Family Residence (Fujimoto) Silkworm Room No. 2
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00015013
- Toshin Journal: Former Sato Family Residence registered as a national cultural property (Japanese)
- https://tjournal.co.jp/local/ueda/post-17134/
- Weekly Ueda: Former Sato Family Residence (Fujimoto) and the silk history of Ueda (Japanese)
- https://www.weekly-ueda.com/post/%E8%9A%95%E9%83%BD%E4%B8%8A%E7%94%B0%E3%81%AE%E6%AD%B4%E5%8F%B2%E3%82%92%E7%89%A9%E8%AA%9E%E3%82%8B-%E6%97%A7%E4%BD%90%E8%97%A4%E5%AE%B6%E4%BD%8F%E5%AE%85%EF%BC%88%E8%97%A4%E6%9C%AC%EF%BC%89
- Ueda City Tourism Association: Fujimoto Sericulture History Museum (Japanese)
- https://ueda-kanko.or.jp/spot/fujimotorekishikan/
Last verified: 2026.09.25
