Miyagino Natto Factory

A Natto Works Founded in 1920

The Miyagino Natto Factory (宮城野納豆製造所, Miyagino Nattō Seizōsho) is a maker of natto and natto starter culture in Ichomachi, Miyagino-ku, Sendai, founded in 1920; seven buildings of the plant it built on this site around 1934 were listed together as Registered Tangible Cultural Properties on September 10, 2019. The walled compound, a little over 3,500 square metres, sits right beside Rikuzen-Haranomachi Station on the JR Senseki Line.

Natto is soybeans fermented with a strain of hay bacillus until they turn sticky and pungent, and it has long been a breakfast staple in eastern Japan. For most of its history it was made by wrapping boiled beans in bundles of rice straw and trusting the bacteria living on the straw. The results were unpredictable, and hygiene was poor.

The founder, Miura Jiro, is credited by Sendai's Board of Education with helping to establish a scientific method of natto making. According to the company, he studied under Hanzawa Jun, the researcher at what is now Hokkaido University who showed that natto could be made reliably by inoculating boiled beans with a pure culture and controlling temperature and airflow. From 1921 Miura cultivated his own strain from rice straw, and the company says it still uses that same line today.

His most influential idea was a fermentation room whose temperature could be adjusted, known as the Miura-style fermentation room or bunkashitsu. Sendai's Board of Education describes it as a contribution to the modern method of producing natto. The firm's boxed natto won a silver prize at the Tohoku Industrial Exposition in 1928, while it was still based in Minami-Koizumi in present-day Wakabayashi-ku, and in 1934 it moved to its current site.

A preface in the 1936 third edition of Hanzawa's handbook on natto production thanks Miura for supplying photographs of his factory, a sign that the new plant had already caught the attention of researchers. The war halted production from 1944 to 1952. Work resumed in 1953, when the second-generation head, Miura Kazuo, developed a rotating pressure cooker for the beans. Plastic containers followed in 1967, and machinery took over part of the hand process in 2003.

Why Seven Buildings Were Listed Together

The seven buildings registered in 2019 are the Natto and Natto Bacteria Production Building, the Aging Building, the Stone Storehouse and Bean Shed, the Break Room, the Boiler Room, the Lignite Hut and the Garage. They carry the consecutive registration numbers 04-168 to 04-174, and all were listed for contributing to the historic landscape of the country.

For decades the site went unnoticed. Its walls hide the buildings from the street, and it was left out of Miyagi Prefecture's survey report on modern industrial heritage published in 2005. That changed in 2015, when the architect Yasui Taeko surveyed the buildings and drew up their plans. The third-generation president, Miura Harumi, decided to keep the buildings in use, carried out repairs including new roofs, and put forward almost every structure on the site for registration.

The Agency for Cultural Affairs notes, building by building, how each conveys the makeup of a modern food factory or its power plant. Read together, the seven trace the whole process: beans stored, weighed, boiled and inoculated, then fermented, cooled and shipped, with the boiler, its fuel shed, the delivery garage and the workers' break room all still in place. Yasui has also pointed out that natto and natto starter are still made here by the methods the company has used since its founding, which she counts as a large part of the site's value.

How the Site Works

Everything turns on the Natto and Natto Bacteria Production Building, which stands at the centre of the site facing south. Its east wing is a single-storey Kirizuma-zukuri workroom; its west wing is a two-storey Yosemune-zukuri block that served as office and living quarters, and its front door is the entrance to the whole works.

Follow the beans and the logic of the layout becomes clear. West of the production building's west wing is the Stone Storehouse, built of local Akiu stone, where soybeans are kept; the wooden Bean Shed behind it is where they are weighed. In the east wing the beans are cooked, dusted with natto bacteria and packed. The packs then ride a small rail trolley along a track running from the production building into the Aging Building, where rows of little fermentation rooms line the south side and the north end is used for cooling and shipping.

The support buildings cluster to the east. The Break Room adjoins the east wing, and the Boiler Room continues to its south, housing a brick lignite-fired boiler that supplied heat for cooking the beans. Lignite fuel was delivered from the street into the Lignite Hut on the southeast boundary. The Garage for the delivery vans stands in the southwest corner, facing east.

The buildings date from two phases. The production building, the Aging Building and the Stone Storehouse and Bean Shed date from around 1934, the Break Room and the Garage from the early Showa years, and the Boiler Room and the Lignite Hut from around 1950.

Visiting and Getting There

The Miyagino Natto Factory is a working private plant, and neither the grounds nor any of the seven buildings are open to the public. The company's website offers no tours, and the perimeter wall means the buildings cannot really be seen as a group from outside. The company's own factory pages and video are the best way to look inside.

Questions about viewing can be directed to the Cultural Properties Division of the Sendai City Board of Education (tel. 022-214-8892). The company's office hours are 9 a.m. to 5 p.m., closed Sundays (tel. 022-256-7223).

The nearest station is Rikuzen-Haranomachi on the JR Senseki Line, about 6 minutes from Sendai Station. The factory adjoins the station, so its outer wall is only a few minutes' walk once you reach street level, next to the Sendai City Miyagino Cultural Center. The cadastral address is 663 and other lots, Ichomachi; the postal address is 4-29 Ichomachi.