Yuasa is a place that carries on both the legend surrounding the origin of soy sauce brewing and the townscape of a brewing industry. At the same time, the entire history of East Asia’s fermented seasonings cannot be explained by a single invention or a single drop. Let’s enjoy the stories handed down in the town while also looking closely at the differences among the actual products.⁰¹⁰⁹¹⁶

Classifications and labeling are based on the JAS standard and the Fair Competition Code, while eating customs and regional information are based on registration documents and official guides.^0304051329

“Koikuchi,” “honjozo,” “marudaizu,” and “Yuasa” are not names of the same kind. On a single label, information layers together: what category of soy sauce it is, how it was made, and what place or maker the product is tied to. Once you sort the names by their role, you’ll find the reason to choose one.⁰⁴⁰⁵

The term “Yuasa shoyu” should also be read by separating the context in which it refers to soy sauce from the region in general, from the context in which it refers to the maker’s name, “Yuasa Shoyu Co., Ltd.” A place name alone does not mean everything is the same method or the same brand. Checking the product name and manufacturer listed on the back label is the first trick.^01212327

Hishio, miso, tamari, shoyu: connected, but not the same

“Hishio” is a term you encounter when tracing old fermented seasonings. What materials it used and what range it referred to differed by era, so it cannot simply be treated as identical to a single bottle of soy sauce today. Miso and soy sauce are historically connected, but that does not mean every modern soy sauce is made by pressing commercially sold miso.⁰⁹¹⁶

“Tamari” also has two uses: a general term for liquid that collects from miso and similar sources, and the JAS category name “tamari shoyu.” “Moromi” likewise appears both as the mash during brewing and as the name of the eating condiment “moromi miso.” Don’t let similarities in terminology cause you to swap one process or food for another.⁰⁴⁰⁷²⁵

What has been passed down in Yuasa is the method for making Kinzanji miso, along with the story of soy sauce making that put to use the liquid that emerged from that process. In the Japan Heritage narrative, the Zen monk Kakushin (also known as Hotto Kokushi) is said to have traveled to Song-dynasty China in 1249 and returned in 1254. The storyline in which he transmitted the method of miso-making he had learned at Jingshan Temple links together the fermentation culture of Yura and Yuasa.⁰¹

He is said to have noticed the liquid that collected in the miso vats, used it as a seasoning, and further refined the process for extracting more of it. This is the story of the “first drop.” However, this should not be read as a proven event in which Kakushin invented today’s soy sauce on a single day. It is best savored as a legend set against the backdrop of the hishio culture of China and the brewing and seasoning history that developed in various regions across Japan.⁰¹⁰⁹¹⁶

Visit Yura for Kakushin, walk Yuasa for the brewing town

Kokoku-ji Temple is located in Yura. It does not stand next to the soy sauce breweries of Yuasa. By visiting the town’s commerce and the temple’s heritage separately, the stage of history comes into view not as a single point but as something spreading across the western coast of the Kii Peninsula.²⁹⁰¹

What the port carried wasn’t only the finished soy sauce

An early-modern production area needed routes for procuring raw materials, salt, and containers, as well as markets for selling its products. Maritime shipping across the Kii Channel, Osaka Bay, and the Seto Inland Sea played a role in connecting all of this. Looking at salt making, wooden-vat making, and the work of merchants and brewers together reveals why a soy sauce town opened itself toward the sea.¹³

The Japan Heritage commentary explains that commerce developed under the protection of the Kishu domain, and that by the Bunka era (1804–1818), the town counted 92 brewing operators. This is not the current number of establishments, but the scale of prosperity at that time as conveyed by later commentary. The townscape that remains offers a gateway to reading that commerce and way of life.⁰¹

To Choshi, Noda, and Tatsuno: the same flavor didn’t simply spread as is

The movement of people and techniques from Kishu to the Boso region is an important thread connecting regional soy sauce history. Meanwhile, in the Kanto region, brewing developed in places like Choshi and Noda, tied to the tastes of consumer markets, raw materials, and transport conditions. Tatsuno, in the Kansai region, is a place to learn about the development of usukuchi. It’s more interesting not to treat each production area as merely a copy of Yuasa’s method—the differences are what make it fascinating.¹³¹⁴¹⁵

Tracing the story and the record through a timeline

The basics of honjozo (traditional brewing) are to cultivate koji mold on the raw ingredients, combine them with salt water, and extract the liquid through decomposition, fermentation, and aging. The main raw ingredients are soybeans, wheat, salt, and water. Here we look at the typical process for koikuchi (regular soy sauce). Not every type and every brewery uses the same proportions or number of days.⁰⁴⁰⁶⁰⁷

First, bringing the ingredients into a “workable condition”

Soybeans are processed by steaming and other methods, while wheat is prepared by its own method, such as roasting and crushing. Adding tane-koji (seed koji spores) to these and cultivating koji mold is called “seikiku” (koji-making). Koji is not made only from rice. In soy sauce, koji made by cultivating koji mold on soybeans and wheat plays the active role.⁰⁶⁰⁷

Soybean protein is the source of amino acids that lead to umami. The sugars produced from wheat starch contribute not only sweetness but also, through microbial fermentation, aroma and other qualities. Salt not only seasons the product but is also involved in the activity of the microorganisms during the mash-making process. Water dissolves the salt and creates the environment in which components and microorganisms work during production.⁰⁶

Koji, moromi, shoyu: watching where the name changes

This table is meant to convey the overall flow. It is not a set of proportions, temperatures, or hygiene procedures for home brewing.⁰⁴⁰⁵⁰⁷

Koji mold, lactic acid bacteria, and yeast each carry out different roles. Broadly speaking, enzymes produced by koji mold break down the raw ingredients, while lactic acid bacteria and yeast convert sugars and other substances into different components. It’s not a simple, single-file relay, but dividing up the roles helps grasp what fermentation actually involves.⁰⁶

The brown color is not simply the result of scorching

The color of soy sauce involves brown compounds produced when amino acids and sugars derived from the raw ingredients react with each other. The color can also change during aging, pasteurization, and storage. It is neither simply the color of something scorched in a pot, nor is it entirely the color of added coloring agents. Looking at color, taste, and aroma together reveals differences that dark versus light alone cannot show.¹⁰⁴⁶³⁴

Even the same raw ingredients don’t guarantee the same taste

Ingredient processing, how the koji is cultivated, which microorganisms are used, temperature, time, finishing—each of these is a condition of production. The wooden vat and the brewery environment are also part of that, but they alone cannot be singled out as the cause of the flavor. Rather than declaring flatly, “It’s because of the wooden vat,” reading into what that particular brewery values makes for a much richer comparison.¹³

Production-method terms are descriptions of how something is made, not a scorecard for the food. Let’s set aside assumptions like “honjozo means nothing has been added” or “defatted processed soybeans mean a substitute for soybeans.” Reading what you want to know one point at a time brings you closer to your own preference.⁰⁴⁰⁵¹²

Honjozo, mixed brewing, and mixing

Honjozo is a method in which koji is mashed and then fermented and aged. Konko-jozo (mixed brewing) is a method where amino acid liquid and the like are added to the moromi, which is then further fermented and aged. Konko (mixing) is a method where amino acid liquid and the like are combined with soy sauce or kiage. The difference is not simply “mixing” as a single point, but at what stage and with what something is combined.⁰⁴⁰⁷

These classifications and the presence or absence of sugars, alcohol, and the like are separate matters to check. The name “honjozo” alone does not make checking the ingredients list unnecessary.⁰⁴⁰⁵

Whole soybeans and defatted processed soybeans

“Whole soybeans” (marudaizu) describes a raw ingredient using soybeans that still contain their oil. “Defatted processed soybeans” (dasshi kako daizu) have had the oil removed from the soybeans, leaving the protein behind. Since the raw material for umami remains, understanding it as “empty pressed residue” would be incorrect. The presence or absence of oil leads to differences in process and composition, but which one you prefer is not determined by a single word on the label.¹²

Wooden vats and tanks

A wooden vat (kioke) is a vessel used to mash the moromi, a tool passed down through generations including repairs and renewals. Tanks, meanwhile, also play a role in organizing management, cleaning, and production. Regional research by academics includes examples of breweries that manage temperature during fermentation even when using wooden vats. “Whether it’s a wooden vat” and “whether temperature is managed” are separate questions.¹³

The label “natural brewing” comes with conditions

The Fair Competition Code sets conditions including that the product must be honjozo, that fermentation must not have been accelerated using enzymes such as cellulase, and that designated additives must not be used. It’s important not to arbitrarily extend this term into a guarantee of wooden vat use or of no heating. If an individual brewery states its own additional standards, read that explanation and choose accordingly.⁰⁵

Koikuchi, usukuchi, tamari, saishikomi, and shiro are not a classification divided only by depth of color. Their raw ingredients, production methods, and the way aroma develops also differ. What follows describes general tendencies for understanding the types, not a table that guarantees the formulation, salt equivalent, or flavor of any individual product.⁰⁴⁰⁸

Usage is just a starting point. You can use koikuchi in light-colored dishes, and there’s nothing wrong with using tamari for something other than sashimi. Try applying the same amount to the same dish and choose based on which flavor you want to bring out.⁰⁸

First the name, then the ingredients, and finally the salt equivalent and storage method. Things you can’t tell from the large product name alone can be read one by one on the back. Even for dashi soy sauce or sweet-style products, don’t fit them into the five soy sauce categories based on the name alone — check the name and ingredients. The amount you use differs between a processed seasoning with dashi added and plain soy sauce.⁰⁵⁰⁷²⁴

Usukuchi and reduced salt belong on different shelves

Usukuchi is mainly a type made to finish with a light color. If you want to choose based on low salt content, don’t go by the word “usukuchi” — look at labeling such as “reduced salt” and the salt equivalent figure. A flavor that feels mild and an actual low salt content are not the same thing.⁰⁸¹¹

Under the Fair Competition Code for soy sauce, “reduced salt” requires, in addition to a salt content of 9g or less per 100g of soy sauce, that the conditions for reduction labeling under the Food Labeling Standards be met. “Usushio / asashio / amashio” (mildly salted) means at least 20% less salt than the standard equivalent soy sauce, with a salt content exceeding 9g per 100g. “Low salt / reduced salt” and similar terms mean at least 20% less than the standard equivalent soy sauce, meeting the Food Labeling Standards conditions for indicating the comparison target, etc. Also, don’t forget not to compare 100g and 100mL as if they were the same figure.⁰⁵⁴¹

Kiage, nama, and ki are different

Kiage refers to the process term for the soy sauce liquid drawn from fermented and aged moromi (mash). “Nama (raw) shoyu” is a labeling term for products that are not pasteurized by heat, and under the Code, this requires treatment equivalent to heat pasteurization. “Ki” (also read as “raw” but written differently) is a separate matter with its own conditions relating to honjozo (traditional brewing) and additives. When the reading differs, the conditions being referred to also differ.⁰⁴⁰⁵

You should not read “nama” as meaning the liquid was simply bottled straight from the vat with no processing, or that it is healthy because the bacteria are still alive. Soy sauce that has been heat-finished also has its own aroma and uses.⁰⁵¹¹

Grade doesn’t decide the flavor you’ll like

JAS has Special, Superior, and Standard grade classifications, evaluated on items such as total nitrogen content, salt-free soluble solids, and color, according to the type. Total nitrogen content is one indicator that looks at things like the breakdown products of raw materials related to umami. However, a higher figure is not a report card saying it suits every dish or every person better. Separately from the grade, you can choose flavor and use.⁰⁴

For “organic” and “additive-free,” check “about what”

Using organic soybeans for part of the product is different from the finished food being certified under organic JAS. Look separately at the certification labeling and the explanation regarding ingredients. For “additive-free” too, what matters is what it explains is not being used. A single word cannot determine safety, health benefits, or even low salt content all by itself.¹⁹²⁰

Kinzanji miso is a miso that is mainly eaten as is. If you were imagining a miso meant for dissolving into miso soup, first try putting some on a small plate and tasting it together with rice or vegetables. Whole grains, the texture of the ingredients, sweetness and saltiness, a hint of ginger or shiso — the enjoyment of this food lies in eating all of that together.⁰³³¹

Names like “namemiso” (miso for licking/nibbling) and “okazu miso” (side-dish miso) are useful for grasping its role of being served in small amounts alongside food. Even though it shares the name “miso” with rice miso or barley miso, the way you approach that first bite is different from when those are used in soup. You can use Kinzanji miso in cooking, but rather than dissolving it right away, it’s recommended to first look at the grains and ingredients.⁰³²⁵³¹

Three grains, four vegetables. A look inside Kishu Kinzanji Miso

In the GI-registered “Kishu Kinzanji Miso,” soybeans, hulless barley (a type of barley), and rice are the three ingredients used for the koji. The ingredients are four: melon (uri), eggplant, ginger, and shiso. Those grains and vegetables are specified as domestically produced, and the production area is Wakayama Prefecture. “Domestically produced” does not mean everything is produced in Wakayama Prefecture.⁰²⁰³

What’s worth noting is that soybeans, hulless barley, and rice are all used as koji. The vegetables aren’t simply added on afterward as garnish either — they’re brewed together with the koji, salt, and sugar, then fermented and aged. Grains remain whole in the final product. The way grains and vegetables meet within a single spoonful is itself tied to the production method.⁰³

This is a condition for a registered regional product. It is not a chart showing that all products across the country labeled “Kinzanji miso” have the same ingredients and formulation.⁰³

A food with a long history isn’t necessarily made to the same recipe it always was

Kinzanji miso has a long tradition behind it, but that doesn’t mean the detailed method from the time it was first introduced is fully known as-is. Even the GI product specification states that the specific early production method is unknown, and instead explains later changes to the method and to sweetness. While enjoying today’s flavor, it’s important not to project today’s ingredient list onto a medieval menu.⁰³

Kinzanji and Jingshan: history preserved in different spellings

Among modern products, alongside the usual spelling of “Kinzanji miso”, you also encounter notations such as an alternative historical spelling of “Kinzanji miso”. Gobo’s Horikawaya Nomura uses the notation an alternative historical spelling of “Kinzanji miso.” On the other hand, the name of the temple in China needs to be verified within the context of tradition and historical sources, and temples with similar characters should not all be lumped together as one. At the point of sale, the surest approach is to first read the manufacturer’s official product name exactly as written.⁰¹⁰³²⁷

How is it different from moromi miso?

Both are sometimes eaten alongside rice or cucumber, but that doesn’t mean they share the same formulation. Ota Kyusuke Ginsei introduces “Hishio,” which uses koji made from soybeans and barley, as a product separate from its Kinzanji miso and rice miso. Rather than going by similarity of name, looking at the explanations of grains, ingredients, and seasoning reveals the differences available to choose from at that shop.²⁵

When comparing products, compare per the same 100g

Below is a comparison of the nutrition facts labeling for individual products published by Marushin Honke. It is not a standard figure for Kinzanji miso as a whole, nor a result of independent measurement.

If the amount eaten at one time differs, the amount of salt consumed changes too. For example, if you eat 10g of a product containing 6.4g per 100g, the calculated salt equivalent is 0.64g. This is a calculation example to illustrate how to think about quantity, not a recommended amount to consume.⁴²

Do you want to affect the color, the aroma, or the umami of the dish? Choosing from that starting point makes it much easier to use different soy sauces appropriately. A clear soup where you want to keep a pale color and a dish you want to grill until fragrant call for different jobs from the sauce. You can use one bottle for everything, or you can try a second bottle to explore the differences.⁰⁸¹¹

The uses of soy sauce here are guidelines based on official explanations of each type, while the comparison steps and ideas about how much to add are suggestions for home use from this encyclopedia. They are not a tasting ranking of any specific product.⁰⁸³¹⁴²

Try separating the roles of before and after heating

The aroma of soy sauce changes with heating. If you separate the use where it blends into the flavor within a simmered dish from the use where you add it near the finish to preserve its aroma, the same single bottle can serve a wider range of purposes. Because heating time and moisture content differ from dish to dish, there is no uniform rule like “always at the end” or “always at the beginning.”⁴⁶

A scene where Kinzanji miso accompanies chagayu

The pairing of Wakayama’s chagayu with Kinzanji miso also appears in official introductions to the region’s food culture. A light, thin rice porridge alongside a grainy miso taken from a small side dish. Rather than dissolving it into the broth, pairing them bite by bite makes it easier to physically understand the difference between a seasoning and a side dish. It’s also an approachable pairing for people trying Kinzanji miso for the first time.⁰¹³¹

Start with just two types. Compare them using the same ingredient, the same amount, and the same temperature. There’s no need to sample large quantities. Choose a bottle you’re used to and one you’re curious about, and try writing down the difference you personally notice before worrying about the brand name.

Mark small dishes A and B, and use an ingredient whose raw materials you’ve confirmed, such as a small identical piece of tofu. Check the aroma lightly, then dip a small amount of each in turn and taste them one after the other. Drink water in between, don’t repeat the tasting too many times, and stop once you’ve noticed a difference. This is a suggestion for enjoying it at home, not a sensory evaluation test conducted by a testing institution.

The final column isn’t about which one “won,” but about “when would you want to use it.” Some days you may prefer a strong flavor, and other days you may want to bring out the ingredients themselves. Not mixing your impressions with objective figures is also a trick for making your own taste comparisons more interesting.

Storage should be decided not just by the type of soy sauce, but by that particular product’s container and labeling. Color and aroma change under the influence of oxygen and temperature. Even if you use it at the dining table, think of the place where it sits unused as something separate. Just keeping this in mind changes how you choose to use it up before it goes bad.¹⁰

While unopened, follow the product’s storage labeling and avoid places exposed to direct sunlight or high temperatures. After opening, refrigeration is generally advised for ordinary bottles, but some products, such as those in freshness-preserving containers, specify different conditions. Don’t judge based on the container alone — read the “after opening” instructions.⁴⁷

The best-before date assumes an unopened product stored under the labeled conditions. That date alone does not guarantee how long the product will keep after it has been opened. Rather than keeping one large bottle around for a long time, choosing a smaller size you can use up is also an option.⁴⁷

Don’t assume that, because Kinzanji miso was traditionally a preserved food, it can be left at room temperature in today’s households. For the products introduced by Marushin Honke, the guidance is to refrigerate after opening and eat it promptly. Portion out what you’re going to eat using clean utensils, and follow the storage conditions labeled on the product you purchased.⁴²⁴³⁴⁴

Even if it says “soy sauce,” that doesn’t mean every product has the same ingredients or use. If you directly equate Japan’s usukuchi with other countries’ “light soy sauce” or “reduced-salt soy sauce,” you can end up mistaking what the color and the salt content actually mean. At first, it helps to separate the explanations into “a type finished with a pale color” and “a product with reduced salt.”⁰⁴⁰⁸

For Kinzanji miso, explaining it in English first as “a miso made from fermented grains and vegetables, eaten alongside rice” helps avoid the misunderstanding that it should be entirely dissolved into miso soup. Keep the product name, and add an explanation of what it’s eaten with and how. This is a useful way to communicate it, especially when giving someone a food they’re trying for the first time.⁰³³¹

Check allergies, gluten, and alcohol separately

The use of soy and wheat, gluten derived from naked barley and similar grains, seafood used in dashi, and any added alcohol are all separate items to check. Because alcohol is generated during the fermentation process, the absence of the word “alcohol” in the ingredients list alone does not guarantee that the product contains no alcohol. Also, alcohol that arises naturally and alcohol added to the product are two separate matters.^06171842

Labels such as vegan, halal, and gluten-free are not uniformly guaranteed just because the food is called “soy sauce” or “Kinzanji miso.” Check the specific product, its raw materials, and its production and certification conditions. It is also important not to explain a dashi-containing product as “plant-based because it’s just ordinary soy sauce.” Please do not recommend a product you cannot verify to someone with dietary restrictions by saying it’s “probably fine.”^04171824

Don’t turn “it’s a fermented food” into a shortcut to health claims

Fermentation is a mechanism for making food. It’s not possible to leap from labeling or origin stories to claims of effects such as “because it’s raw, the microbes work in your gut” or “because it’s traditional, it prevents disease.” This encyclopedia’s starting point is to enjoy soy sauce and Kinzanji miso as flavor and food culture, while keeping an eye on salt-equivalent content and portion size.⁰⁵²⁰

If you want to try making it at home, start with a proper hands-on lesson

Preparing koji, salt content, temperature, containers, and judging when something is off are all different from simply leaving something to sit for a long time. Please do not use this encyclopedia’s process diagrams as a formulation chart for home preparation. If you want to try it, choose a workshop with an instructor who explains hygiene, storage, and how to handle it after taking it home, or a supervised hands-on experience run by a producer, and follow the specified procedures. It’s also important not to expect the same level of safety while changing conditions on your own judgment, such as drastically reducing the salt.⁰⁶²³

The historic townscape, the museum, the working brewery, and the shops each let you see different things. Deciding on one purpose first makes it easier to choose where to stop by. The following are entry points confirmed through official public information, not the editorial team’s personal visit accounts.

The distinctions between tours, exhibits, and sales are based on the information provided by each operator or municipality.^{2223242628293035}

If Visiting by Train, Don’t Mix Up the Two Stations

JR Yuasa Station is the entry point for walking around Yuasa town. Kadocho also publishes walking directions from the same station. If you’re heading to Kokoku-ji Temple, check the directions from JR Kii-Yura Station instead. Don’t plan as if everything is within the same walking area just because you got off at Yuasa Station.²²²⁹

Start in Yuasa by pairing the museum, town walking, and shopping together. If you’re interested in the production method, book a guided tour or experience at Kuyo-gura. For Yura and Gobo, plan travel time and the day’s purpose separately. This is a travel suggestion to avoid packing your itinerary with too many destinations.

The café at Kuyo-gura also offers soft-serve ice cream made with soy sauce. It’s a fun way to encounter this ingredient in a sweet form, but check the menu for ingredients and allergens. Don’t confuse the conditions of soy sauce alone with those of a sweet that contains dairy and other ingredients.²³

Keeping a tradition alive requires not just preserving old tools, but also having the people and materials to remake them. Wooden barrels involve repair and renewal, timber procurement, and the skills of the craftspeople who make them. Yuasa Shoyu Co., Ltd. announced in October 2025 that it had introduced two domestically sourced cedar wooden barrels. As of the announcement, the soy sauce brewed in the new barrels was expected to be completed around 2028. This is not yet a new product available for purchase in stores.³³

A researcher’s survey of the Kii Peninsula describes the work of adjusting koji-making temperature and humidity to match the weather and the condition of the raw materials. If you’re thinking about how to respond to climate change, understanding these on-site conditions is the starting point. Predictions such as “Yuasa soy sauce will become impossible to make in a certain number of years due to warming” cannot be derived from this material alone.¹³

Even After Pressing, There’s Somewhere for It to Go

After the soy sauce liquid is extracted, byproducts such as soy sauce lees remain. The Kikkoman Group has introduced initiatives to use soy sauce lees as animal feed and to repurpose separated soy sauce oil as fuel. This is an example from that group, and it doesn’t mean every brewery in Yuasa does the same thing. Looking beyond just the drop you use, to the resources before and after it, reveals brewing as an industry.³²

When Choosing Your Next Bottle, One More Question

In addition to “which dish should I use this for,” ask “what work went into creating this flavor?” The answer might be on the label. You might find it in the brewery’s explanation, or in the chunky texture of Kinzanji miso.

The fermentation culture of Yuasa and Wakayama is not just a story from a distant era; it reaches today’s dining table. Let a single drop and a single spoonful be your entry point to exploring the flavors you love and the story behind them.

About the Information in This Article

Information verified as of: September 24, 2026. Brewing formulations and durations, salt content, ingredients, and storage methods vary by product. Figures in comparison tables are based on the specified subjects and units. Standards and labeling systems, product specifications, business hours, tours, reservations, menus, and the like are subject to change, so please check the official information at the linked sites and the product labeling before purchasing or visiting. Past announcements of new introductions and subsequent expected product completion dates are noted separately. Historical legends are presented as legends.