Kojiya Tarobei Shoten Koji Chamber

What Is the Kojiya Tarobei Shoten Koji Chamber?

The Kojiya Tarobei Shoten Koji Chamber (糀屋太郎兵衛商店糀室, Kōjiya Tarobē Shōten Kōjimuro) is a half-sunken room for growing koji, built around 1893 on the Kojiya Tarobei Shoten property in Uomachi, Matsusaka City, Mie Prefecture, and registered as a Registered Tangible Cultural Property on February 4, 2021.

It is a small single-storey timber building of 16 square meters, standing west of the inner storehouse and facing south. It is the smallest of the four registered buildings, yet the Agency for Cultural Affairs calls it the core facility of koji production. A summary published by Mie Prefecture in 2020 notes that koji is still being made here.

Why the Koji Chamber Was Registered Differently

The other three buildings at Kojiya Tarobei Shoten were registered for contributing to the historic landscape. The Kojiya Tarobei Shoten Koji Chamber alone was registered as a structure that would not be easy to reproduce.

Hidden from the street, it adds little to the townscape. What earned its place is the specialized construction for raising koji. The chamber is counted among the buildings put back up within the same year after the Great Matsusaka Fire of March 29, 1893, and according to Mie Prefecture it is still used for the same work today.

Wrapped in Plaster, Roof and All

A Rounded White Shell

The chamber is built as a low-pitched Dozo-zukuri structure, and the whole of it, roof included, is coated in Shikkui plaster. Mie Prefecture singles out its exterior, with walls and roof finished in a rounded, kamaboko-like curve (the shape of a loaf of Japanese fish cake). There are no roof tiles; it reads as one continuous white mass.

At the upper right of the front, a plasterer has drawn a mayu, an "eyebrow," in black plaster. A single dark stroke on the white surface shows that craft went into even this small work building.

The Half-Sunken Interior

Inside, the floor is set below ground level, and the roof is carried on sloping rafter beams (Nobori-bari). The floor and walls are rendered in mortar. In the southeast corner a raised curb holds the straw mats used in koji making.

Koji is made by dusting steamed rice with mold spores and keeping it warm and moist while the mold spreads. Koji rooms in general need to be shielded from swings in outside temperature, and a sunken floor under a thick plaster skin appears to answer that need.

Seeing the Kojiya Tarobei Shoten Koji Chamber

The Kojiya Tarobei Shoten Koji Chamber is a working building at the back of the property, and we found no notice of it being opened to the public (checked September 2026). It is also a place where food is made, so please do not ask to go in.

From the street you can see only as far as the front of the Shop and Main House. If the shop is open, the counter is where koji from the chamber may be on sale. Directions are on the Kojiya Tarobei Shoten page.