A Warm Room for Growing Mould
The Muro of the Fukui Sanshiro Residence (福井三四郎家住宅室, also written Fukui Sanshirō-ke Jūtaku Muro) stands at 1320 Katsuno in Takashima City, Shiga Prefecture, dates from the early 19th century, and was entered on the national register of Tangible Cultural Properties on 23 August 1999.
The word muro means an enclosed chamber, and the Agency for Cultural Affairs describes this one precisely: a storehouse held at constant temperature for resting koji. Koji is the mould culture Aspergillus oryzae, grown on steamed grain and used to break starch and protein into sugars and amino acids. Soy sauce, miso, sake and rice vinegar all begin with it. The Fukui family brewed soy sauce on this site, and this small building is where the first stage of that process took place.
Growing koji demands warmth held steady for several days while the mould spreads through the grain. Too cold and it stalls; too hot and it dies or turns. Before thermostats, the answer was mass: thick earthen walls that absorbed the heat given off by the fermenting mass itself and released it slowly back into the room. This building is a piece of climate-control equipment made of mud, timber and tile.
Why It Was Registered
Registration came under the criterion of contribution to the historic landscape, with registration number 25-0117, notified on 7 September 1999 in the nineteenth round of registrations. The Agency for Cultural Affairs files it under secondary industry rather than housing, the same classification given to the main house, while the storehouse on the same lot is filed under housing. The paperwork itself preserves the division between the family's working premises and its domestic ones.
The structure is single-storey dozō construction under a tiled roof, two and a half ken square, with a total floor area of 29 square metres. A ken here is roughly 1.8 metres, so the chamber itself is a little over four metres on a side. Open-sided work areas run along the front and the north flank, unwalled spaces where the grain could be spread, turned and cooled.
What lifts the building above the merely functional is its roof. A gabled vent sits on the ridge, releasing the heat and moisture that koji production generates in quantity. The front slope then runs down long and unbroken over the open work area, giving the whole a profile close to nagare-zukuri, the asymmetric roof form used for Shinto shrine main halls. The resemblance is a by-product of function rather than an attempt at religious reference, and it makes this small building the visual accent of the property.
Visiting
The building sits inside the grounds of Takashima Village, the revitalisation project launched in 1995 by members of the former Takashima Town chamber of commerce. The main house on the street front operates as Building No. 2 with a restaurant and bakery; other structures across the site have been converted for shops and workshops over the years, and the numbering of the buildings follows the order in which they came into use.
Interior access to the muro depends on how it is currently being used, so check at one of the Takashima Village shops or at the Omizo Jinya Somon information centre rather than assuming. The grounds can be walked during business hours at no charge, and photographing the exteriors is unrestricted.
Approach from the front if you can. The long front slope of the roof, seen from below and at an angle, is the thing worth the walk. Look for the small gabled structure riding the ridge, and for the boundary between the enclosed chamber and the open-sided work platform beside it.
The wider district rewards an unhurried visit. Omi-Takashima Station on the JR Kosei Line is about five minutes away on foot. The Omizo Waterside Landscape, which includes the castle site, the water channels of the old town and the inner lake of Otomegaike, was selected as an Important Cultural Landscape in January 2015, and the restored Omizo Jinya Somon gate nearby opens from 10:00 to 17:00, closed Wednesdays.
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Q&A
- What is the Muro of the Fukui Sanshiro Residence?
- A small early 19th-century building used for culturing koji mould, the starter for soy sauce brewing. Its thick earthen walls held an even temperature over the several days the mould needed to develop.
- Why does the Muro of the Fukui Sanshiro Residence look like a Shinto shrine?
- Its front roof slope extends long and low over an open-sided work area, producing a silhouette close to the nagare-zukuri form used for shrine main halls. The resemblance follows from how the building was used rather than from any religious intent.
- Can visitors go inside the Muro of the Fukui Sanshiro Residence?
- Interior access depends on the building's current use, as the site is operated commercially by the Takashima Village cooperative. The grounds are open during business hours without charge, and the exterior can be seen and photographed freely. Ask at a Takashima Village shop about going inside.
- How large is the Muro of the Fukui Sanshiro Residence?
- Two and a half ken square, roughly four metres on a side, with a total floor area of 29 square metres. It is single-storey earthen-walled construction with a tiled roof and a gabled ventilator on the ridge.
- What else can I see at the Fukui Sanshiro Residence site?
- Two further registered buildings: the late 18th-century main house on Honmachi-dori, now Takashima Village Building No. 2, and an early 19th-century storehouse behind it that held the family's household goods. All three were registered on the same day in 1999.
Basic Information
| Name | Muro (Koji Room) of the Fukui Sanshiro Residence / 福井三四郎家住宅室 |
|---|---|
| Location | 1320 Katsuno, Takashima City, Shiga Prefecture |
| Designation | Registered Tangible Cultural Property (Structures); registration no. 25-0117 |
| Year Designated | Registered 23 August 1999; notified 7 September 1999 |
| Quantity | 1 building |
| Dimensions | Earthen-walled construction, single storey, tile roof; floor area 29 m². Two and a half ken square |
| Owner | Takashima Village Business Cooperative |
| Public Access | Exterior viewable from the grounds during business hours; interior access depends on current use |
References
- National Cultural Properties Database, Agency for Cultural Affairs: Muro of the Fukui Sanshiro Residence
- https://kunishitei.bunka.go.jp/heritage/detail/101/00001280
- Biwako Takashima Tourism Guide: Takashima Village
- https://takashima-kanko.jp/spot/2018/06/post_211.html
- Biwako Takashima Tourism Guide: Omizo Jinya Somon
- https://takashima-kanko.jp/spot/2024/04/post_327.html
- Omizo Waterside Landscape Community Council: Omi-Takashima Omizo Waterside Walk
- https://oomizo.shiga.jp/
Last verified: 2026.08.04