About the Yamasan Soy Sauce Mashing Room and Boiler Room
The Yamasan Soy Sauce Mashing Room and Boiler Room (ヤマサン醤油仕込み場及びボイラー室) is a mid-Taisho single-story timber work building attached to the three-story brewery at the Yamasan works in Umaki, Shodoshima-cho, Kagawa Prefecture, listed as a Registered Tangible Cultural Property in 2003.
It wraps around the west and south sides of the three-story building in an L. The mashing room joins from the west: a single-story gabled (Kirizuma-zukuri) block with a pantile roof (Sangawara-buki) and an east-west ridge, widened to 11 meters by a lean-to (Geya) along its south side. With the boiler room on the south, the whole covers 224 square meters.
Mashing, shikomi in Japanese, is the step where koji is combined with brine to start the fermenting mash. It is where soy sauce making really begins, and here it happens in a room built directly onto the three-story brewery.
Why the Mashing Room and Boiler Room Were Listed
The Yamasan Soy Sauce Mashing Room and Boiler Room was listed for its contribution to the historic landscape. More than any other building on the site, it shows how Yamasan grew by adding working spaces around the three-story core. On its own it is a plain single-story shed; seen together with the tall building it serves, it completes the heart of the brewery.
The boiler room deserves a second look. A room named for a boiler at the center of a Taisho-era brewery suggests that Yamasan had brought in steam-powered equipment by then.
What to Look For at the Yamasan Mashing Room and Boiler Room
The roof of the Yamasan Soy Sauce Mashing Room and Boiler Room rests on a King post truss, the same Western-style framing used in the three-story building itself. Finding the same technique in the attached sheds suggests the two were planned as one project.
The boiler room roof carries a raised ventilator to let heat and steam escape. Compare it with the ventilator on the nearby pressing shed: in both cases, the job of the room below shows up in the shape of the roof.
On the south side of the mashing room, note how the lean-to drops a step below the main gable and runs along the whole long wall, stretching the working floor outward.
Visiting the Yamasan Soy Sauce Mashing Room and Boiler Room
Because the Yamasan Soy Sauce Mashing Room and Boiler Room is attached to the three-story brewery, you will see it when a tour visits that building. Tours are by reservation, and whether you go inside depends on the guide on the day.
If you want to see the ventilator or the trusses, mention it when you book. Check with the guide about photography.
- 📍 Plan Your Visit to Kagawa
- Find tours, activities & transport passes near Yamasan Soy Sauce Mashing Room and Boiler Room
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Q&A
- What is the Yamasan Soy Sauce Mashing Room and Boiler Room?
- The Yamasan Soy Sauce Mashing Room and Boiler Room is a mid-Taisho single-story timber building wrapped around the west and south sides of the three-story brewery, covering 224 square meters.
- When was the Yamasan Soy Sauce Mashing Room and Boiler Room registered?
- The Yamasan Soy Sauce Mashing Room and Boiler Room was registered as a Registered Tangible Cultural Property on September 19, 2003.
- What does mashing mean at the Yamasan Soy Sauce Mashing Room and Boiler Room?
- At the Yamasan Soy Sauce Mashing Room and Boiler Room, mashing (shikomi) means combining koji with brine to start the fermenting soy sauce mash.
- What are the roof features of the Yamasan Soy Sauce Mashing Room and Boiler Room?
- The Yamasan Soy Sauce Mashing Room and Boiler Room has king post truss framing, a raised ventilator on the boiler room roof, and a lean-to on the south side that widens the mashing room to 11 meters.
- Can visitors see the Yamasan Soy Sauce Mashing Room and Boiler Room?
- The Yamasan Soy Sauce Mashing Room and Boiler Room is seen on Yamasan's reserved tour, often together with the three-story brewery. Ask when booking how much of the interior is shown.
Basic Information
| Name | Yamasan Soy Sauce Mashing Room and Boiler Room |
|---|---|
| Location | 140-2 Ishii-ko, Umaki, Shodoshima-cho, Shozu-gun, Kagawa Prefecture |
| Designation | Registered Tangible Cultural Property (Building) |
| Year Designated | Registered 2003 |
| Quantity | 1 building |
| Dimensions | Building area 224 m² (single-story timber frame) |
| Owner | Not listed in the Agency for Cultural Affairs database |
| Public Access | Grounds shown on guided tours by reservation |
References
- Agency for Cultural Affairs Database: Yamasan Soy Sauce Mashing Room and Boiler Room
- https://kunishitei.bunka.go.jp/bsys/maindetails/101/00003620
- Shodoshima Town: Yamasan Soy Sauce Co., Ltd. (Japanese)
- https://www.town.shodoshima.lg.jp/kanko/miru/sangyo/yamasan.html
Last verified: 2026.09.24
