A Room for Growing Koji

The Omori Soy Sauce Brewery Koji House (大森醤油醸造所麹庫) is a single-storey timber koji room of the early Taisho period in the south-west corner of a soy sauce brewery at Obe, Tonosho Town, Shozu District, Kagawa Prefecture, and was registered as a Registered Tangible Cultural Property (structure) on March 2, 2004 (Agency for Cultural Affairs).

The Agency for Cultural Affairs records single-storey timber construction roofed in tile and slate, with a building area of 61 square metres, registration number 37-0204.

Making Koji for Soy Sauce

According to the Shodoshima Soy Sauce Cooperative, soy sauce making on the island is traditionally said to date from the 1590s, and the island, long a major salt producer, turned to soy sauce when salt fell into oversupply in the late Edo period. The Japan Tourism Agency notes that up to 400 breweries operated on Shodoshima around the turn of the 20th century, of which about 20 still work today.

Soy sauce begins with koji: steamed soybeans and roasted wheat cultured with koji mould. The Omori Soy Sauce Brewery Koji House was built for this stage, and its design shows the effort to regulate temperature (Agency for Cultural Affairs). The brewing storehouses and pressing shed on the same site are also registered.

Value as a Registered Cultural Property

The Omori Soy Sauce Brewery Koji House was registered as a structure contributing to the historic landscape of the country. The Agency for Cultural Affairs records it as a two-chamber koji room with double outer walls and a ceiling of bamboo slats.

What to Look For

The Agency for Cultural Affairs describes the Omori Soy Sauce Brewery Koji House on a stone base on a north-south axis, 4.5 by 3 bays, gabled and pan-tiled.

Outside, the Omori Soy Sauce Brewery Koji House has vertical boarding below and white plaster above, with windows for regulating temperature set high up at ceiling level (Agency for Cultural Affairs).

Visiting

No public access information has been confirmed for the brewery; please view it only from the road without entering the premises. The address is 3272-1 Obe, Tonosho Town.

See the group page Omori Soy Sauce Brewery for all three buildings.

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Q&A

QWhen was it built?
AIn the early Taisho period (Agency for Cultural Affairs).
QWhat was it for?
AGrowing koji for soy sauce, in two chambers (Agency for Cultural Affairs).
QHow was temperature controlled?
ABy double outer walls, a bamboo-slat ceiling and high windows for regulating temperature (Agency for Cultural Affairs).
QWhat does it look like?
AA building on a stone base with vertical boarding below and white plaster above (Agency for Cultural Affairs).
QWhen was the Omori Soy Sauce Brewery Koji House registered?
AOn March 2, 2004.

Basic Information

NameOmori Soy Sauce Brewery Koji House (大森醤油醸造所麹庫)
Location3272-1 Obe, Tonosho Town, Shozu District, Kagawa Prefecture
DesignationRegistered Tangible Cultural Property (Structure)
Year DesignatedRegistered 2004/03/02 (Heisei 16)
Quantity1 building
DimensionsTimber, single storey, tile and slate roof, building area 61 square metres
OwnerNot listed in the national database
Public AccessNo public access information

References

Omori Soy Sauce Brewery Koji House (Database of National Cultural Properties, Agency for Cultural Affairs)
https://kunishitei.bunka.go.jp/heritage/detail/101/00004039
Omori Soy Sauce Brewery Brewing Storehouses (Database of National Cultural Properties)
https://kunishitei.bunka.go.jp/heritage/detail/101/00004041
Omori Soy Sauce Brewery Pressing Shed and Work Area (Database of National Cultural Properties)
https://kunishitei.bunka.go.jp/heritage/detail/101/00004040
History of Shodoshima Soy Sauce (Shodoshima Soy Sauce Cooperative)
https://shima-shoyu.com/history/
Shodoshima Soy Sauce: An Aromatic Tradition (Japan Tourism Agency Multilingual Database)
https://www.mlit.go.jp/tagengo-db/en/R2-01894.html

Last verified: 2026.10.11