When Masaru Okazaki met Satomi Terada in Tokyo in 1996, neither imagined their young romance would lead to a life of sake brewing. But once Masaru met Satomi’s parents and visited Terada Honke, he decided to go all in on her family’s business. He eventually abandoned his job as a filmmaker in the city, changed his last name to Terada and assumed the role, alongside Satomi, as the 24th-generation operator of Terada Honke.

They had big shoes to fill — not just centuries of history, but also the visionary work of Satomi’s father, Keisuke Terada. Like most sake breweries in the second half of the 20th century, Terada Honke had turned to industrial production, looking to maximize output to keep pace with the boom-time consumption of postwar Japan.

But in the 1980s, citing health problems and a desire to reconnect with a more natural approach to brewing, Keisuke changed course, trading machines and industrial ingredients for organic rice, wild yeast and a mixture of muscle and finesse.

Over the past two decades, Masaru has deepened Terada Honke’s dedication to this unpredictable, high-touch approach to brewing sake. One of a handful of producers using exclusively wild yeast, according to Mr. Terada, it is the only brewery in Japan to cultivate its own koji, a mold used to ferment many of Japan’s staple products, including soy sauce and miso.

This style of brewing requires skill and patience. (Wild yeast ferments slower than industrial yeasts.) If a batch comes out with too much acidity — natural sakes are often high in lactic acid — Mr. Terada and his team will need to blend it with other sakes to balance out the flavors and prevent any waste.

For centuries, the rhythms of Terada Honke’s production have been imprinted on Kozaki, a small riverside community two hours north of Tokyo. Its plots of rice on the edge of town announce the planting and harvest seasons, the plumes of steam in winter signal a time of transformation and its Okura festival in mid-March celebrates the end of the brewing season.

Over its 24 generations, Terada Honke has built schools, worked with local poets and artists and collaborated with farmers to revive ancient rice strains and foster organic agriculture in and around Kozaki.

This type of relationship between sake breweries and their local communities was commonplace for centuries, but as they continue to shutter, Japan stands to lose a central pillar of its society.

“If sake continues to disappear, it will not merely be the decline of a single industry,” Mr. Terada said. “We will lose the very foundations of what makes Japan unique: agriculture rooted in local communities, fermentation culture, human connections and even festivals and seasonal traditions.”

For Mr. Terada and his team, the importance is not enshrining the traditions of a bygone era; it’s fostering an environment where sake culture can continue to evolve.