
Nestled near the Ibogawa River in Tatsuno City, Hyogo Prefecture—where the river flows into the Seto Inland Sea—Suehiro Shoyu has been brewing usukuchi (light-colored) soy sauce using time-honored methods since 1879. Tatsuno City, known as the birthplace of usukuchi soy sauce, has been crafting this delicacy since the 1600s.
Usukuchi soy sauce is distinct from koikuchi (dark) soy sauce, which most people consider the standard. While usukuchi is lighter in color, it retains a rich flavor and aroma and is slightly saltier than koikuchi. Chefs favor usukuchi for dishes where they want the flavor of soy sauce without darkening the dish's color. Suehiro’s usukuchi shoyu, in particular, has a delicate rose-colored hue, showcasing its exceptional quality.
The difference between usukuchi and koikuchi goes beyond color and saltiness. Usukuchi uses more wheat in its brewing process, which adds a natural sweetness that balances the higher salt content. It’s also aged for a shorter period—just 2.5 months in summer or up to 8 months in winter, as the fermentation process quickens with heat.
Suehiro Shoyu remains committed to traditional brewing, a dedication that’s increasingly rare. Once home to 60 soy sauce breweries, Tatsuno City now has only a handful left, including one of Japan’s largest producers. Suehiro stands out by sourcing soy and wheat from Japan and brewing in small batches. Interestingly, they age their soy sauce in fiberglass tanks rather than traditional cedar. However, the secret lies in their wooden brewery building, where specific strains of beneficial bacteria thrive, imparting Suehiro’s soy sauce with its unique flavor.