In Japan, an automotive light bulb manufacturer pivots to growing mushrooms 

Japan’s Shizuoka prefecture is famous for its tea, Mount Fuji, and manufacturing. It’s home to many small companies that produce parts for the big car makers (like Toyota, Honda and Nissan). 

One of those smaller companies, Oigawa Denki, an automotive light bulb manufacturer, recently made a surprising pivot — expanding into growing mushrooms.

Nearly a decade ago, the company’s management, which employs about 100 people at a light bulb factory in the small town of Ieyama, realized that they would need to adapt as the industry steadily changed to LEDs. 

The auto industry’s shift toward electric vehicles and LEDs is good for reducing emissions, but Nobuaki Hamaguchi, an economics and business researcher, says the transition can be difficult for companies that make car parts.

“In my opinion, there are three possible responses for automotive suppliers that will eventually lose jobs as a result of electrification,” he said, adding that they can keep making parts for combustion engines and focus on the remaining market share in Japan (which has been relatively slow to adopt EVs); target developing countries where parts are needed to repair old cars; or shift its business to other industries where it can apply that technology. 

That last option is the most risky and rare. But for Oigawa Denki, it would’ve been extremely expensive to retool the entire factory to make LEDS, and there is already a lot of competition in that space, according to a company spokesperson. So, they assembled a team of board members and employees to explore other options. They landed on growing a rare mushroom called Hanabiratake, or “flower petal mushroom,” also known as cauliflower mushroom. 

Hanabiratake is notoriously hard to grow, so the light bulb engineers used their precision and data analysis skills. According to the company’s president, Takayuki Sasaki, it took a few years of trial and error to create a good system.

Then, in 2020, Oigawa Denki opened a new factory dedicated to growing mushrooms under the brand name Hohohotake. The mushroom facility is about 30 minutes away from the light bulb factory in an old tea warehouse surrounded by rice fields. A dozen Oigawa employees now work at the new facility.

“Until four years ago, I was making light bulbs,” said Kazuki Morishita, manager of the mushroom facility.  

Now, he oversees the production of 60,000 packages of mushrooms per month. He explained that for both light bulbs and mushrooms, controlling temperature and humidity are important. Just as they did with light bulbs, the mushroom team collects data, and if something goes wrong, they can use that data to troubleshoot.

Visitors must wear a disposable lab coat, hairnet, and face mask to enter the cultivation area. The mushrooms are grown on sterilized sawdust in plastic bags, lined up neatly on industrial metal racks. Fans circulate fine mist in a series of rooms, where the lighting and humidity are adjusted for each stage of growth. In a final room, frilly mushrooms pop out of the tops of the bags, ready to pick.

After harvest, the mushrooms are sorted for quality and packaged to ship to restaurants and supermarkets. Morishta explained that some are even exported to Singapore, Hong Kong and Malaysia. By next year, the company is aiming for 500 million yen in annual sales, or about $3 million.

As demand for incandescent bulbs inevitably shrinks, Oigawa Denki may be able to move even more of their employees into mushroom production.

Researcher Hamaguchi said that transitioning to new industries could make it more appealing for the next generation to take over these companies. 

“This is currently a critical moment whether these fading businesses should be maintained or inherited to the future generation or not.”

Oigawa Denki is still an outlier, but the Japanese government recently launched a project to help automotive parts manufacturers innovate and move into new industries. There may be more surprising pivots in the years to come.