Soy sauce（Shoyu） | Sushiblog

What is the difference between Ki-joyu, Nama-shoyu, and Nikiri-shoyu?

A photo of shoyu — The appearance of shoyu

Choosing soy sauce based on its manufacturing process significantly impacts the aroma, taste, and appearance of your dishes. Three common types—nama-shoyu (unpasteurized soy sauce), ki-joyu (standard brewed soy sauce), and nikiri-shoyu (cooked soy sauce)—each have distinct characteristics and uses. Understanding these differences will help you select the right soy sauce for enhancing the natural taste of ingredients and achieving the perfect balance in your dishes.

Nama-shoyu (なま醤油)

A photo of nama-shoyu — The appearance of nama-shoyu

Nama-shoyu is an unpasteurized soy sauce characterized by its rich aroma and flavor. It skips the typical pasteurization process (sterilization of microorganisms) used in regular soy sauce, instead relying on precise filtration to remove yeast and microorganisms, ensuring freshness and safety. Because it is unheated, applying heat during cooking further enhances its aroma, allowing you to enjoy a vibrant color that highlights the natural hues and flavors of ingredients, along with a mellow, smooth umami taste.

Due to its living microbial nature, it maintains freshness at room temperature when stored in a sealed double-layered bottle that prevents exposure to air. Refrigeration after opening is sometimes recommended. It is ideal for sashimi, cold dishes, or as a finishing soy sauce, where enhancing the aroma and color of ingredients is desired.

Incidentally, unpasteurized pressed soy sauce is sometimes called “kiage-shoyu.” Since it hasn’t undergone heat sterilization or filtration, it’s soy sauce that retains microorganisms like lactic acid bacteria and yeast.

Ki-joyu (生醤油)

Ki-joyu is originally a term from the culinary industry, referring to soy sauce made solely from “soybeans, wheat, and salt,” which has undergone pasteurization. Pasteurization is the process of heating raw soy sauce to inactivate microorganisms and enzymes, thereby adjusting its aroma and flavor. This heating deepens the color, creates the characteristic savory aroma and taste of soy sauce, and produces a mellow overall impression.

Under JAS regulations, the only permitted additive is salt. Products labeled with only “soybeans, wheat, salt” on their ingredient list are ki-joyu. This signifies a pure soy sauce with no additional seasoning, suitable for a wide range of dishes like simmered and grilled foods. It also boasts a longer shelf life and more stable flavor compared to nama-shoyu. For sushi, ki-joyu is preferred over nikiri-shoyu when the soy sauce’s inherent, wonderful aroma is prioritized.

Nikiri-shoyu (煮きり醤油)

Nikiri-shoyu is a seasoned liquid made by adding mirin, sake, and sometimes dashi such as bonito broth to soy sauce, then heating it to evaporate the alcohol. “Nikiri” refers to the cooking technique of heating mirin or sake to evaporate its alcohol content, said to have originated with Edo-period street stall sushi. Evaporating the alcohol softens the sharpness of the soy sauce, enhancing the umami without overpowering the flavor of the seafood toppings. Furthermore, adding dashi incorporates its umami components, creating a deeper, more complex flavor. In sushi restaurants, it is used for all types of seafood sushi toppings.

Summary:

Nama-shoyu is best used for raw or cold dishes, as it brings out the natural color and aroma of the ingredients. Ki-joyu is a versatile, pure soy sauce that works well in cooked dishes when the soy sauce’s own flavor is desired. Nikiri-shoyu is a seasoned, umami-rich soy sauce, perfect for enhancing the taste of all types of sushi toppings.

The Birth of Edomae Sushi Through Soy Sauce

A photo of soy sauce — The main ingredients of soy sauce are soybeans, wheat, and salt.

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.

What is Murasaki?

A photo of Murasaki — The quality of soy sauce is determined by its clear reddish-brown color.

By the time you know some of the jargon used in sushi restaurants, you are already fully immersed in the world of sushi. The first jargon you will probably learn is Murasaki. Jargon is a word, phrase, or jargon that is understood only among certain professionals and their peers, so it is used among people who work at sushi restaurants. It is not used by customers, of course.

Now, what does Murasaki mean in a sushi restaurant? Actually, “Murasaki” is a jargon for soy sauce. So, we did some research to find out how soy sauce came to be called Murasaki. Originally, soy sauce was a food culture of the late Edo period, so there should be plenty of documentation of its use. However, even after researching, ” Murasaki ” ‘s origin was unclear. There are various theories, but here are some of them.

There is a theory that soy sauce has the alias “Murasaki” because of soy sauce’s reddish-brown color.

In ancient and medieval times, the reddish-brown color was called “purple” in Japan, and the color of soy sauce dropped on a small plate was reddish-brown, which is why soy sauce was called “Murasaki” in Japan.

This may seem surprising since soy sauce appears to be black. Generally, dark soy sauce has a clear reddish-brown color. If you put it in a glass or something and look at it through the light in a bright place, you will see it has a beautiful reddish color.

Some people believe that the alias “Murasaki” for soy sauce comes from purple being a noble color.

During the Edo period, although Edo became the political center of Japan, it still lagged behind Kyoto, Osaka, and other cities in the Kamigata region in terms of culture. The leaders of the Edo shogunate, who wanted to build a unique culture in Edo, apparently conceived the idea of making purple, which had long been considered a symbol of nobility, the symbolic color of Edo culture. It is said that the 8th shogun, Yoshimune, had purple dye studied in the Edo Castle.

It is also known as Edo purple (Edomurasaki), the color of the headband that the main character wears in popular Kabuki performances. There is no reason why the Edomurasaki color used by actors in Kabuki, the greatest entertainment of the Edo period, should not be popular. Edomurasaki is also known as the color that symbolizes the aesthetic sense of the chic Edokko, characterized by its deep blue tone in contrast to the reddish Kyoto purple (Kyomurasaki).

In this way, purple culture grew up in Edo. It is widely believed that this cultural background and the fact that dark soy sauce, which was an expensive and precious seasoning at the time, was almost purple, gave rise to the alias Murasaki. As a synonym for “precious,” dark soy sauce in the Kanto region came to be called Murasaki.

Some people believe that Murasaki, another name for soy sauce, comes from the black soybeans of Tamba.

Tanba no kuromame are large, high-grade soybeans originating from the Tanba region of Hyogo Prefecture. It is said that the name “Murasaki” was derived from the purple color of soy sauce made from these black beans.

There is a theory that the name “Shihou” (It means purple mountain) is derived from the elegant name for Mount Tsukuba.

Shihou is said to have originated from the purple color of the surface of the mountain when illuminated by the setting sun. It is also speculated that purple was an appropriate color for Mt. Tsukuba, which has also been revered as a sacred mountain. The theory is that soy sauce was produced in large quantities near the foot of Mt. Tsukuba during the Edo period, giving soy sauce the alias “Murasaki”. Shihou (紫峰) is also used today in the Shibanuma shoyu brand located at the foot of Mt. Tsukuba.

Finally, it is said that soy sauce came to be called Murasaki actually after the Meiji period (1868-1912). If this is correct, the second theory seems to be wrong. Many soy sauce manufacturers have been around since the Edo period, but their websites do not mention the origin of Murasaki at all. It is Jargon after all, so it is not for outsiders to make claims. In addition to Murasaki, one should avoid using Agari (which means three things in Japanese: Green tea in a sushi restaurant, dead fish, and a finished dish), Oaiso (Check), Namida (Wasabi), and Aniki (sushi material that has been prepped first, i.e., old).

Related contents:
Types of Shoyu (Soy sauce)

How can you tell how a person was raised and their food culture by the way they use soy sauce?

At high-class restaurants, the minimum required nikiri soy sauce is brushed on to the piece, but at restaurants frequented by the general public, customers dip their sushi in as much sauce (soy sauce that includes chemical seasonings) as they like. In fact, there is a gimmick here. The high-class restaurant provides an opportunity for their customers to eat sushi toppings in the most delicious state possible, but the restaurants for the general population allow customers to eat casually with sauce, a daily necessity. This changes how topping ingredients are selected. If the sushi is going to be dunked into the soy sauce, then the topping must have an appropriate fat content that won’t be overpowered by the soy sauce. Therefore, instead of a coastal tuna, a farm-fattened tuna with oily fat is preferred. It is often said that farm-fattened products are too rich, but it is also said that they have an impact that isn’t overpowered by the sauce they are enjoyed with.

Related contents: SOY SAUCE FOR SUSHI

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Revision date: July 18, 2019

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Do you know why sauce made from chemical seasonings dissolved into soy sauce is used for sushi that commoners eat?

There is a sensor on the tongue that feels the degree of saltiness. This prevents us from eating too much of things that are extremely salty. Chemical seasonings confuse that sensor. The chemical seasoning palliates the degree of saltiness felt by the tongue. Even if you were to, for example, dunk your sushi into the soy sauce and chemical seasoning mixture, it won’t feel salty. If you eat sushi with the sauce, you can take in a high volume of sodium, which is a pleasure trigger for the human body, without feeling the saltiness on your tongue. In other words, it may be more accurate to say that with commoner sushi, you actually drink the sauce, not dip into it.

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Revision date: June 11, 2019

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Where should soy sauce be applied to the sushi?

A photo of applying shoyu — When dipping sushi into the soy sauce, it is most common to turn it slightly (almost upside down) and dip the topping side—not the rice.

Soy sauce is more than just a condiment for sushi—when used properly, it enhances the flavor of the sushi topping and brings out a perfect balance with the vinegared rice, which is already delicately seasoned. However, using it incorrectly can easily upset this harmony.

The most delicious way to eat sushi at restaurants where the sushi chef applies Nikiri shoyu (a soy sauce mixture perfectly evaporated with sake) for you is just the way it was prepared. However, at restaurants where sauce is not applied for you, the sushi is eaten by dipping it in soy sauce. The soy sauce used for dipping is provided for you at the counter or table. Many restaurants use the same evaporation formula for the dipping soy sauce.

Soy sauce for dipping is put into a small dish for use, but don’t put in too much. It depends on the depth of the small dish, but the diameter of the circle of soy sauce after being poured should be approximately 25mm.

When dipping sushi into the soy sauce, turning it upside down (although it will be somewhat tilted) and dipping the topping seems to be the most common method. If you keep the topping on the bottom when you put the sushi in your mouth, the flavors of the soy sauce and the fish are in complete harmony and the delicious taste spreads through your mouth. There is also an opinion that turning the sushi upside down for dipping is unacceptable practice. There are also some with the opinion that whether to eat with your hands or chopsticks depends on the situation.

Make sure not to get any soy sauce on the vinegared rice (shari). You don’t want to add unnecessary saltiness to the Shari, which has already been seasoned. It would be a terrible waste to cancel out the exquisite balance of the topping, wasabi and Shari with the saltiness of soy sauce.

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Revision date: July 3, 2025

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Why is sushi eaten with soy sauce (shoyu)?

Many different things all over the world are share the name “sushi”. However, when Japanese people hear this word they think of “nigiri sushi”. Of course outside of Japan, it probably more commonly refers to sushi rolls.

Similarly, the way soy sauce is used also differs greatly between people in Japan and those in other countries. The soy sauce used for nigiri sushi is not primarily intended to add saltiness. Rather, it serves to suppress the fishy odor of raw fish and to enhance umami by adding the many amino acids found in soy sauce. Soy sauce is especially rich in glutamic acid, which, when combined with inosinic acid naturally present in the fish, creates a synergistic umami effect. Think of it more like an important background role to the sushi that isn’t meant to stand out.

On the other hand, overseas, sushi such as rolled sushi is generally eaten cold, and since the flavors such as sweetness, umami, and aroma fade at low temperatures. when it cools, there is a tendency to use more soy sauce. To compensate for this flavor fade, stronger seasonings such as sriracha sauce, eel sauce, and teriyaki sauce are often used, so that the flavor of the sushi does not get lost even when it cools.

There is also a big difference in the concept of sushi sauce. In Japan, there is no such word as “sushi sauce”. Neither chefs nor the general population has heard this term. However, the term is easy to imagine what it would be, so hearing the word “sushi sauce” would probably lead Japanese people to assume it meant nikiri shoyu or nitsume, which are used in nigiri sushi. Also, soy sauce, or “shoyu” as it’s called in Japanese, is not considered to be a type of “sauce” in Japan. But what about in other countries? Sushi sauce has a distinctive, assertive flavor and is added to bring out multiple layers of flavor. There are also many types of sushi sauce such as sriracha sauce, spicy mayo, mango sauce, ponzu sauce, tonkatsu sauce, eel sauce, tamari sauce, teriyaki sauce, dynamite sauce and others. They each play an important role in bringing out the flavors of sushi rolls that otherwise wouldn’t be apparent.

In other words, as the definition of sushi definition changes across borders, the definition of sushi sauce changes too. However, what both sushi sauce overseas and Shoyu in Japan have in common is that they complement the sushi they are used for.

Now we would like to explain a bit about the Shoyu used in nigiri sushi.

Edomae style sushi was created during the Edo period in Japan (1804-1830). The expansion of the soy sauce culture of the Edo area (currently Tokyo) had a big influence on the creation of Edomae style sushi. In a time when refrigeration and other technology had not yet been developed, soy sauce played an important role not only in taste, but also in preservation. A surprising number of tasks in the Edomae style utilize the scientific effects of soy sauce.

First of all, lightly applying just a small amount of Nikiri shoyu (sushi sauce) on the sushi topping brings out its natural umami flavor and also creates an attractive glossy glaze. Scientifically, this technique leverages the odor-masking properties of soy sauce, which contains sulfur-containing compounds such as methanethiol (methyl mercaptan). These compounds chemically interact with and neutralize unpleasant raw fish odors, effectively masking the “fishy” smell and enhancing the overall sensory experience.

Historically, zuke (soaking fish in nikiri soy sauce) was not limited to tuna but applied to other types of fish as well. This traditional method takes advantage of the bacteriostatic effects of soy sauce—its high salt concentration and presence of antimicrobial peptides inhibit the growth of harmful bacteria like Escherichia coli (E. coli), thereby preserving freshness and enhancing food safety.

Tsume, a thickened sushi sauce made by boiling down soy sauce with simmered　conger eel sauce, mirin and sugar, demonstrates the thermal chemical reactions involved in soy sauce cooking. The Maillard reaction between amino acids from the soy sauce and reducing sugars creates a rich brown glaze and complex aroma that stimulates appetite. This reaction also contributes to the development of subtle caramelized flavors, enhancing the sauce’s depth.

In addition, adding a small amount of soy sauce when making rolled egg omelets (tamagoyaki) enhances and harmonizes the natural sweetness and umami of the eggs and other ingredients. This effect is primarily due to the presence of free amino acids in soy sauce. Sweetness is imparted by amino acids such as glycine, while umami arises from the combined action of approximately 20 different amino acids. Among these, acidic amino acids like glutamic acid and aspartic acid, as well as basic and neutral amino acids such as lysine and alanine, contribute most significantly to the overall umami profile.

Soy sauce is generally overshadowed by the sushi topping and vinegar rice, but soy sauce plays an important role in bringing out and enhancing the delicious taste of the sushi.

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Revision date: June 13, 2025

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