The Deliciousness of Nigiri Sushi and the Role of Soy Sauce
The appeal of nigiri sushi lies in the balance between the vinegared rice
’s gentle acidity and the seafood’s natural umami. Soy sauce elevates this harmony, acting like a quiet but essential partner in the background—a supporting role without which sushi would feel incomplete.
So-called Kansai-style sushi, such as oshizushi, bozushi, and hakozushi, which developed from preserved foods, involves seasoning not only the vinegared rice but also the sushi toppings. Therefore, it can be eaten without soy sauce. However, Edomae sushi uses fresh ingredients and values the inherent flavor of those ingredients. This necessitated a soy sauce that wouldn’t compromise the natural taste of the ingredients but rather enhance it.
Soy sauce contributes more than taste. It also helps neutralize the fishy odor that vinegar alone cannot remove. For instance, in hikarimono like kohada, saba, and aji, even a light brush of soy sauce softens the smell and polishes the flavor.
Beyond flavor and aroma, soy sauce also plays a role in preservation. Just as vinegar and salt protect sushi from spoilage, soy sauce has long been recognized for its bacteriostatic properties. In this way, it supported the development of Japanese cuisine, which relies on raw ingredients even in Japan’s humid climate.
Whether through its color, taste, fragrance, or hygienic qualities, soy sauce is woven into the very foundation of Japanese culinary culture.
Traditional Soy Sauce in Edomae Sushi
Edomae sushi originally used seafood caught in Tokyo Bay, but from the Edo period onward, fish such as tuna were also brought in from distant waters. These were often marinated in soy sauce in a technique called zuke. The name itself comes from this marinade, and to this day, sushi shops that uphold Edomae traditions still serve maguro zuke. Thanks to modern freezing and storage methods, fresh tuna is available year-round, so zuke is no longer a necessity—but its deep, mellow flavor endures.
In the past, soy sauce was rougher and less refined than today. To suit their needs, sushi chefs would cook and season it, creating nikiri shoyu (“simmered soy sauce”). This is typically made by gently simmering soy sauce with 10–20% mirin, sometimes with sake, bonito stock, or water. After about 30 minutes, when bubbles form, the heat is turned off. The word nikiri—literally “simmered to completion”—is said to come from this step.
Although improvements in modern soy sauce mean some shops no longer use nikiri, many traditional Edomae sushi restaurants still brush it onto their nigiri, just as they continue the practice of zuke.
Among simmered toppings (nimono) like anago, shako, and hamaguri, another essential sauce is tsume (or nitsume). Made by reducing the simmering liquid of anago or hamaguri with soy sauce, mirin, and sugar until it becomes a rich glaze—about one-tenth its original volume—tsume has been perfected in each restaurant’s own style.
Traditionally, tsume is prepared when high-quality anago arrives. The head and bones are simmered to create a flavorful broth, which is strained and then combined with soy sauce, mirin, and sugar. It is slowly reduced over half a day into a glossy sauce. The choice of soy sauce here is critical, and many sushi chefs say that the depth of a restaurant’s tsume reflects its true character.
Conclusion
In sushi, soy sauce is far more than a condiment. It balances flavors, refines aromas, preserves freshness, and embodies tradition. The delicate ways in which it is used—through zuke, nikiri, or tsume—are a testament to the craft of Edomae sushi and remain central to the essence of sushi culture today.