The weight of the sushi rice ball is determined the moment the sushi chef forms it.
Nigiri sushi sold at street stalls during the Edo period is said to have been roughly the size of a small rice ball today, weighing about 50 to 70 grams per piece. According to historical records such as Morisada Manko (守貞漫稿), eating just two or three pieces was considered a sufficient light meal. Eventually, complaints that the sushi was “too large and difficult to eat” led to it being halved in size and served two pieces at a time, though there are several theories about why this change occurred. This adjustment allowed diners to enjoy a greater variety of toppings in a single visit.
The weight ofshari and toppings is actually decided by each restaurant; there is no industry standard.
So how did this weight come to be? The answer lies in a unit of rice that has been deeply ingrained in Japanese life.
In Japan, the smallest unit for measuring rice is called ichigo (一合), which equals 150 grams (180 cc). This is also considered a standard portion for one meal, and household rice cookers often have markings based on multiples of this unit. Cooking an ichigo yields approximately 300 to 330 grams of cooked rice. While actual consumption varies depending on age and gender, the concept of “ichigo equals one meal” has been established for centuries. This unit has been passed down not only in households but also in sushi restaurants, where chefs use it to calculate the required cooking volume and determine how much rice to prepare at once.
This unit is also scalable: ten times ichigo equals ishou (一升). Until about 30 years ago, it was common for sushi restaurants to cook nishou (二升) of rice at a time, and commercial rice cookers sized for this purpose were available. Today, chefs typically cook rice according to the number of reservations, often calculating one serving as a little over ichigo.
Looking further back, during the post-war rationing period, there was a “commissioned processing system” where rationed rice could be brought to sushi shops for processing. Bringing ichigo of rice to a sushi shop would get you seven pieces of nigiri sushi and one nori roll, equivalent to about ten pieces of nigiri. Working backward from this system, it is estimated that the rice weight per piece in the post-war period was approximately 30 to 33 grams.
This weight served as a standard benchmark for some time after the war. Gradually, alongside changes in food culture, this standard also shifted. Responding to customer requests to enjoy more sushi toppings, the amount of rice per piece gradually decreased. By the late Showa period, it was around 20 grams. Today, in the Reiwa era, the mainstream is 10–15 grams per piece in central Tokyo sushi restaurants and 15–20 grams in regional areas.
Sushi chefs carefully consider the thickness of the fish, its fat content, and the temperature and humidity of the rice to achieve the “balance that tastes best in one bite.” In recent years, partly due to rising ingredient costs, there has been a trend toward reducing the rice even further. Some pieces now weigh less than 10 grams, though it is said that reducing them any more makes it difficult to discern subtle differences in flavor, especially in white fish.
The weight of the rice is not merely a matter of quantity; it represents the “art of the bite,” shaped by 200 years of Japanese food culture and aesthetic sensibility.
This title might seem like a uniquely Japanese question. However, in neighboring countries like Korea and China, flounder (karai) and halibut (hirame) are also commonly eaten, and efforts are being made to cultivate them.
In many other countries, however, these fish are not distinguished and are often lumped together as “flatfish.”
One reason is the broad range of species covered by the English term “flounder.” For instance, many species like flounder, plaice, halibut, lemon sole, common dab, Pacific Dover sole, and fluke are all grouped under “karei.” Even the names alone can be confusing.
The common method to distinguish hirame and karei is the rule that when placed belly-side down (the white side), the hirame faces left and the karei faces right. However, there are exceptions like Numagarei (Starry flounder).
Species in the Pleuronectidae family, whose eyes are on the right side, are known as “righteye flounders,” while those in families such as Paralichthyidae and Bothidae, with eyes on the left, are called “lefteye flounders.”
Similarities and Differences Between Karei and Hirame
Both karei and hirame belong to the order Pleuronectiformes and share very similar shapes and colors. They both have flat bodies, are asymmetrical, and possess the unique characteristic of having both eyes on one side of their body.
What is Karei?
The Illustration of Karei
Flounder encompasses a vast number of species with a wide distribution range. In Japanese coastal waters alone, approximately 40 species have been identified, including Magarei (Yellow striped flounder), Meitagarei (Ridged-eye flounder), Ishigarei (Stone flounder), and Makogarei (Marbled flounder). The species caught also vary by region.
As they are relatively inactive fish, their flesh is characterized as soft and rich in fat. They feed on small fish, ragworms, and small crustaceans, resulting in a small mouth shaped like a “pursed mouth.” Additionally, their eyes are located on the right side of their body.
While fresh specimens can be eaten as sashimi, they generally have a slight distinctive flavor. Therefore, they are typically enjoyed cooked through methods like simmering, frying, deep-frying, or drying.
What is Hirame?
The Illustration of Hirame
Compared to karei, hirame has fewer species and a narrower distribution, making it relatively rare. Its scientific name is Paralichthys olivaceus, and it is a premium fish found in the coastal waters of Japan and Korea.
Hirame has well-developed muscles for agile movement, resulting in firm flesh. It has a large mouth and sharp teeth for catching small fish and crustaceans, and its eyes are located on the left side of its body.
When eaten raw, it has a crisp, firm texture that turns tender and flaky when cooked. It’s known for its mild flavor and delicate umami. It is popular as a premium ingredient for sushi and sashimi, and in French cuisine, it is also used in main dishes like meunière.
Its peak season runs from late autumn to early spring, with the winter variety, “Kanbirame,” boasting particularly rich fat content and exceptional flavor.
Conclusion
While karei and hirame may look similar, they have distinct differences in taste, texture, and ecology. In Japan, summer Makogarei (Marbled flounder) and winter Bastard halibut (Hirame) are considered premium fish, highly prized in sushi restaurants and traditional Japanese restaurants. Understanding these differences enhances the enjoyment of dining at sushi establishments.
When sauce is about to drip, do you catch it by cupping your hand like a plate with the hand opposite your chopsticks? This is commonly called “Tezara (手皿: Te means hand and zara means plate).” It often appears on Japanese TV during meal scenes.
While it might seem elegant, it’s actually considered bad manners in Japanese dining etiquette, so it’s best to remember this. You should be especially careful during important occasions. The basic etiquette for Japanese cuisine is to hold the bowl or dish in your hand while eating, so the correct way is to use the sauce in a small side dish, not your hand.
However, there are times when small side dishes aren’t provided, like when eating out or at home. In those cases, the basic Japanese approach is to hold the bowl itself close to your mouth for dishes with sauce. Alternatively, you can use techniques like lightly cutting the sauce with the tips of your chopsticks before bringing it to your mouth to eat neatly without using your hands.
Why is using your hand as a plate considered bad manners? If sauce drips onto your hand and stains it, you’ll need to wipe your hands with an oshibori (wet towel), creating extra laundry. Oshibori are meant for wiping hands before eating. If they get stained with food sauce, they may require stain removal, causing trouble for the restaurant.
Furthermore, while it’s common, seeing someone use their palm as a plate and then bring the food to their mouth can feel somewhat unhygienic and vulgar, even if the person themselves doesn’t mind. Depending on the situation, it’s considered bad manners during a proper meal.
In Japan, holding bowls and small dishes is considered polite.
In Japanese dining culture, holding bowls and small dishes is considered polite. Proper etiquette dictates lifting bowls and soup bowls to your mouth, while flat or large dishes should not be lifted—specific manners exist for each type of vessel. Using a serving dish instead of tezara is rooted in these uniquely Japanese dining customs.
Of course, during casual meals at home or with friends, you might unconsciously use your hand as a plate. While it often isn’t a major issue in daily life, it’s especially important to refrain from doing so at formal occasions, kaiseki dinners, or when dining with seniors. Being mindful of etiquette according to the situation will make your dining manners appear more refined.
It’s a gesture that anyone can easily do, but it’s best to avoid it at formal occasions. It may even look as if you’re drawing attention to a spill, so using a side plate or small dish is always the better choice.
Vegetables, fish, and meat each have their own “peak season” when they taste their absolute best.
It’s often said that when it comes to food, freshness is everything. However, greater freshness doesn’t always mean better flavor. Each type of food, such as vegetables, fish, and meat, has its own “peak ripeness” when it tastes its best.
When it comes to fish, the strong belief that “freshness is everything” can sometimes prevent us from fully appreciating its value. Consider fish that are still swimming before the customer’s eyes and then prepared on the spot. While its texture is unique and firm, its umami is weak, and its flavor is lacking. Yet, the notion that “fresh equals delicious” remains deeply ingrained, creating a mindset where belief in freshness outweighs actual flavor.
Let’s take this opportunity to reexamine what truly constitutes the perfect time to enjoy food at its most flavorful.
Vegetables, after harvest, continue breathing, consuming their internal sugars and nutrients while losing moisture, which causes their freshness to decline. To suppress this respiratory activity, effective methods include cold storage, packaging that prevents moisture evaporation, or storage in an environment with low oxygen and high carbon dioxide levels.
On the other hand, vegetables like potatoes and sweet potatoes become more delicious through aging. When potatoes are stored at low temperatures, cold-induced sweetening occurs, breaking down starch into sugar and increasing sweetness. Sweet potatoes also undergo curing after harvest (It forms a protective cork layer, preventing pathogen invasion and suppressing decay). Storing them at a specific temperature and humidity allows the starch to saccharify, enhancing their sweetness and sticky texture. However, apart from these specific examples, vegetables generally lose their freshness over time, so eating them right after harvest is when they taste best.
The optimal time to eat fish varies by species. Coastal migratory fish like sardines and mackerel spoil quickly, making freshness extremely important. These contain EPA, a beneficial fish oil, but since it is vulnerable to heat and oxidation, it is best to choose fresh, high-quality fish for raw consumption.
Even among blue-backed fish, large pelagic migratory species like tuna and yellowtail are different. If they are too fresh, their umami flavor is weak. The umami components increase once rigor mortis subsides and aging begins, reaching their peak flavor.
Furthermore, white-fleshed fish like red seabream and flounder also require careful handling. While Ikejime techniques are used to preserve freshness, freshly caught fish offer a firm, crisp texture. However, umami compounds increase after rigor mortis sets in, meaning “freshness” doesn’t necessarily equate to “deliciousness.”
Sushi chefs fully understand that the ideal eating time varies by fish species. They also fully understand that freshness ensures good texture. On top of that, they strive to balance seemingly conflicting conditions like optimal eating time and texture. In Japan, it’s not uncommon for fish caught by local fishermen to arrive at major city fish markets the same day. Some even arrive at the market still alive. So, freshness alone is something anyone can obtain.
Next, let’s look at meat. Chicken has a small body, and rigor mortis sets in quickly, within just 1 to 2 hours after death, allowing umami to develop rapidly. On the other hand, it also loses freshness quickly. Therefore, it’s safe to say that freshness is absolutely vital for chicken.
On the other hand, large animals like pork and beef require time for rigor mortis to subside, followed by maturation. The recently popular “dry aging” is a traditional method where meat is matured for about a month at 1-2°C while being exposed to airflow, resulting in tender, flavorful lean cuts. Additionally, “wet aging,” practiced in Japan for centuries, involves vacuum-sealing the meat and resting it at 0–2°C for 1–2 weeks, a method that also enhances umami.
Thus, meat isn’t necessarily more delicious the fresher it is; rather, aging increases umami components like inosinic acid, leading some to even say “some even say it tastes best when it’s on the verge of spoiling.” In other words, freshness and deliciousness don’t always go hand in hand.
In other words, the notion that “freshness equals deliciousness” isn’t always accurate; each ingredient has its own “peak flavor” period when it tastes best. What matters is not blindly trusting freshness, but understanding the characteristics of the ingredient and discerning its optimal eating window.
First, let’s confirm where chutoro and otoro are located on the tuna using a cross-section diagram of the fish’s midsection.
An illustration of cross section
Looking at the tuna cross-section, the center part is red meat (Akami), while the surrounding areas closer to the skin are medium fatty (chutoro) and extra fatty (otoro). However, the borders aren’t clearly defined like this, so it’s merely a guideline. If the cut is closer to the tail, it will be just red meat.
Next, when the tuna is dissected, as shown in the illustration below.
An illustration of kuromaguro cutting daigram
The tuna is broadly divided into three main sections from the head: “Kami (Near the head)”, “Naka (Central section)”, and “Shimo (Near the tail)”. The back side is divided from the head downwards as “Sekami (se means back),” “Senaka,” and “Seshimo,” while the belly side is divided as “Harakami (hara means belly),” “Haranaka,” and “Harashimo.” Sushi chefs purchase these sections by width, measured from the index finger to the little finger. This width corresponds exactly to the size of one piece of sushi.
Now, let’s get to the main topic.
Basically, “otoro” refers to the fatty belly section of bluefin tuna or southern bluefin tuna. While various tuna species exist, this term is limited to bluefin and southern bluefin tuna. The term “otoro” isn’t applied to yellowfin or bigeye tuna, though yellowfin tuna can still be fatty. Japanese supermarkets sometimes use the term ‘toro’ for promotional purposes. In-season Albacore (bincho tuna) has exceptionally rich fat, and that cut is sometimes called “bintoro.” Depending on the cut, it can be divided into truly otoro-like otoro and otoro closer to akami-like chutoro.
Otoro generally includes all of the harakami and part of the haranaka. Furthermore, otoro also exists in the kama section near the pectoral fins. Otoro, much like marbled beef, is marbled with white fat. This gives it a rich, melt-in-your-mouth texture. However, some sushi chefs dislike it being too fatty and prepare it as aburi (seared) or zuke (marinated in soy sauce) to balance it with the shari (vinegared rice). Since otoro yields less per fish than akami or chutoro, its price is inevitably higher.
Chutoro, on the other hand, is found on both the belly and the back. It has a base of lean red meat with patches of white fat mixed in. It balances the savory flavor of the lean meat and the sweetness of the fatty tuna, making it universally popular. It consistently ranks among the top favorite sushi toppings for Japanese people. Some parts of the back section also yield a prized cut called setoro. In sushi restaurants, it is the second most expensive tuna cut after otoro.
Incidentally, farmed bluefin tuna and southern bluefin tuna tend to have a higher proportion of fatty parts (toro) compared to wild tuna. This is because they are raised in confined cages with limited exercise and are fed high-fat feed.
The question then arises: where exactly is the boundary between otoro and chutoro?
In reality, there is no clear-cut definition. The distinction is made by tuna wholesalers and sushi restaurants based on years of experience and practical knowledge.
One initiative in producing regions involves branding fish. When certifying branded fish, various criteria are used. One of these is the fish’s fat content. This is objective data and significantly impacts the fish’s deliciousness. The method involves simply touching the fish with the tip of a measuring device, taking only a few seconds. For example, the peak fat content of mackerel imported from Norway to Japan is reportedly around 25-30%.
For otoro, this value is over 20% and can reach 40%. Chutoro is often said to be 15-20%, but such standard values actually don’t exist.
Sushi chefs determine whether it’s chutoro or otoro by cutting the purchased portion into akami, chutoro, and otoro. If the fat content is 15%, it should be classified as chutoro, but if the sushi chef says it’s otoro, then it becomes Otoro.
Wasabi, a vegetable native to Japan, is traditionally served with raw fish dishes such as sashimi. While it has antibacterial properties, its primary role is to enhance the flavor of the fish. Japan has numerous aromatic vegetables, including wasabi, ginger, myoga, green onions, and sansho pepper, among others. Each possesses a unique aroma and aromatic compounds. Adding these to other foods or mixing them during cooking stimulates the taste buds, significantly enhancing the flavor of the dish. Since all these aromatic vegetables have antibacterial and sterilizing effects, they are often served with sashimi and similar dishes.
The pungent flavors of these aromatic vegetables can be broadly categorized into three types: the sharp, stinging heat of wasabi; the fiery, burning heat of chili peppers; and the numbing, tingling heat of sansho peppers. Each type has different components responsible for its distinct heat. Let’s examine them individually.
The pungent component in wasabi is a substance called sinigrin. Sinigrin itself has no pungency, but when the cells are broken down by grinding or similar processes, exposing sinigrin to oxygen in the air causes the enzyme myrosinase to produce a substance called allyl isothiocyanate. This allyl isothiocyanate is the pungent component in wasabi and Leaf mustard or Mustard greens. Wasabi is a plant in the Brassicaceae family, and sinigrin is a substance widely found in vegetables of this family. The pungent taste in other Brassicaceae plants like Mustard cress or Daikon mustard also comes from sinigrin. Wasabi simply contains a particularly high amount of it.
There are two types of wasabi: Sawa wasabi and Yama wasabi. Sawa wasabi is the common, green variety you see most often. Yama wasabi, on the other hand, is the horseradish served with roast beef and similar dishes. Although both are wasabi, their shape and color are completely different. Yama wasabi resembles spicy radish and is used as the base for prepared wasabi paste and powdered wasabi. It has low moisture content and is large in size, resulting in a high yield, making it well-suited for processed products.
Wasabi has been consumed since the Heian period, with records indicating it was eaten mixed into dishes like grated yam broth. At that time, there seemed to be established rules: carp sashimi was served with wasabi vinegar, sea bream sashimi with ginger vinegar, and sea bass sashimi with tade vinegar. Given the era’s hygiene concerns, it’s likely a considerable amount of aromatic vegetables were used. Wasabi began to be eaten with soba noodles, now commonplace, around the Edo period. Originally, spicy radish was served alongside soba. However, when radish was unavailable, wasabi was substituted. It is said that wasabi became a staple because it masked the distinctive fishy odor of the bonito flakes in the soba dipping sauce. Generally, it’s hard to imagine wasabi replacing radish.
Next, when it comes to chili peppers in Japan, Takanotsume (Bird’s eye chili) and Shichimi togarashi (seven flavor chili pepper) are common. Bird’s eye chili is often added to preserved foods such as rice bran pickles, and it has also been traditionally kept for medicinal purposes. This is because Bird’s eye chili also has antibacterial properties. It offers significant health benefits, burning body fat, warming the body, opening pores, and promoting sweating. It is especially effective in winter for raising body temperature. In summer, eating spicy food induces sweating, allowing moisture to evaporate along with body heat, thereby lowering temperature. The capsaicin in Bird’s eye chili promotes fat breakdown and accelerates the breakdown of glycogen in the liver and muscles. Consequently, it not only stimulates the stomach and improves blood circulation but also activates digestive movements within the internal organs, boosting appetite. It is effective during winter when lack of exercise reduces appetite, and also combats summer fatigue-induced loss of appetite.
Chili peppers have also been widely used in preserved foods like pickles, miso, and tsukudani. Their intense pungency and antibacterial properties enhance the shelf life of ingredients, making them a cherished seasoning that supports Japanese dietary habits.
The numbing spiciness of sansho comes from a compound called sanshool. Sanshool increases gastric acid secretion, making it a perfect match for rich, fatty dishes like eel. It also contains an aromatic compound called diterpene, which boosts immunity and enhances antioxidant effects. The name “sansho” (山椒) itself comes from the mountain-scented fruit that is spicy like pepper. Sansho is known as Japanese pepper in English, making it an iconic spice of Japan.
Furthermore, sansho has been utilized in diverse dishes by selecting either the berries or leaves. It is also used in preserved foods like tsukudani and chirimen sansho, enhancing ingredient preservation through its refreshing aroma and antibacterial properties. Additionally, in ancient times, it was valued medicinally as the herbal remedy “Shokushō (蜀椒),” prized for its stomach-strengthening and anthelmintic effects.
In other words, the practice of always serving wasabi with sushi and sashimi is not merely a custom. It is a tradition born from the convergence of scientific reasons like sterilization and antibacterial properties, the culinary ingenuity of maximizing the umami of fish, and the wisdom cultivated by the Japanese people throughout history. Wasabi is more than just a condiment; it is passed down to modern dining tables as a “key component” that elevates the dish’s overall quality.
The appearance of Kinmedai yakishimozukuri. Only the skin is seared.
In Japanese cuisine, it is common for the same cooking method to have different names depending on the season or context, which often leads to confusion. A good example of this is the distinction between yushimo and yakishimo. While they are similar, they are not identical, and understanding the difference is important.
The word shimo (霜) literally means “frost.” In cooking, shimofuri refers to a preliminary treatment in which food is briefly exposed to heat—by pouring boiling water over it, dipping it in hot water, or lightly searing it—so that the surface turns white, resembling frost. It is suitable for fish with beautiful skin or fish that are delicious when eaten with the skin on.
It also refers to the preparation step, similar to kawasimo or yushimo, where the fish is briefly dipped in hot water to remove scales and bloodline before preparing Arani (粗煮) or kabutoyaki (兜煮).
Shimofuri technique removes odors, sliminess, and excess fat while sealing the ingredient’s umami. It also firms the flesh and adds elasticity.
Yushimo (湯霜) comes from yu (hot water) and shimo (frost). It is a type of shimofuri in which the surface of fish or meat is treated with boiling water, either by dipping it quickly into hot water or by pouring hot water over it. The food is then immediately cooled in ice water and the moisture is removed before further preparation. This method is also known as yubiki (湯引き).
When used for sashimi, it is called yushimozukuri (湯霜造り). In this preparation, hot water is poured over the skin side of a fish fillet to soften the skin, after which the fish is chilled, the moisture is removed, and it is sliced. The result is an elegant appearance, with curled skin that enhances both flavor and presentation.
The term yushimozukuri refers not only to the cooking technique itself but also to the sashimi dish prepared using that method.
Yakishimo (焼霜), on the other hand, comes from yaki (to grill) and shimo (frost). This method involves lightly searing the surface of fish or meat until it develops a touch of browning, then cooled in cold water. Like yushimo, it removes excess fat and odor, but it also imparts a subtle roasted aroma. When used for sashimi, it is called yakishimozukuri (焼霜造り). This preparation is widely applied to fish such as red seabream, chicken grunt, barracuda, largehead hairtail, blackthroat seaperch, daggertooth pike conger, yellowtail, Spanish mackerel, bonito, and mackerel.
Depending on the style, the fish may be seared while still in fillet form (saku), or after being cut into sashimi slices. Just like yushimozukuri, the term yakishimozukuri refers both to the cooking method itself and to the sashimi dish created through that method.
Additionally, kawashimozukuri (皮霜造り) refers to sashimi in which the skin has been blanched in boiling water or over an open flame. This technique is also called matsukawazukuri (松皮造り) because, when applied to fish such as sea bream, it creates a pattern that resembles pine bark (matsukawa means pine bark). It enhances the umami of the skin while eliminating any fishy odor. It has the same meaning as Shimofuri and Yushimo.
In short, both yushimo and yakishimo are forms of shimofuri. Yushimo uses boiling water, while yakishimo uses direct heat from searing. Though their purpose is similar, each creates a distinct flavor, texture, and visual appeal, showcasing the ingredient in a uniquely Japanese way.
Grilling is more commonly done with meat than with sushi toppings.
Both Aburi and Tataki are Japanese cooking techniques that involve exposing food to high heat, but they differ in both purpose and process.
Aburi means “to sear,” and refers to lightly grilling the surface of food while leaving the inside raw.
In sushi, aburi is often applied to fatty cuts like salmon or tuna, where the flame enhances aroma, melts fat, and creates a contrast between the charred surface and the fresh interior. Some chefs use handheld gas burners, though Edomae-style masters often disapprove because of the faint odor left by the gas. For them, aburi is not about making the fish richer, but about controlling fat so the sushi remains balanced.
Other methods such as charcoal grilling, ovens, or iron plates can also be used, producing different aromas and textures. Aburi also appears in vegetables—like peppers or eggplants whose skins are charred and peeled—and in desserts such as crème brûlée or baked custard pudding, where caramelized surfaces are essential.
Tataki, in contrast, is more polysemous. In its seared form, tataki refers to quickly grilling the surface of fish or meat, then cooling it and slicing it.
Unlike aburi, tataki is always finished with seasonings: the slices are eaten with condiments such as soy sauce, ginger, garlic, or other pungent garnishes. This seasoning process is essential to the identity of tataki. The best-known example is katsuo no tataki from Kochi, where bonito is straw-seared, chilled in ice water, and served with generous amounts of aromatic condiments.
The term tataki also extends to finely chopping fish into a mince or even a paste, and to vegetables like cucumber or burdock root that are pounded to soften their texture, but in comparison with aburi, it is the seared and seasoned preparation that is most relevant.
Thus, while both techniques highlight the interplay of cooked and raw, aburi serves primarily as an aromatic finish that enhances natural flavor, whereas tataki is a preparation that combines searing with deliberate seasoning. This requirement of seasoning after searing marks a fundamental difference between the two.
When most people think of wasabi, they picture a bright green paste with a strong, nose-tingling heat. In reality, what is served in most sushi restaurants around the world—including in the U.S., Europe, Asia, and China—is usually imitation wasabi.
This is not because restaurants want to mislead customers, but because real wasabi is incredibly difficult to grow and very expensive. The Wasabia japonica plant needs pure spring water, cool temperatures, and several years of careful cultivation, which makes large-scale production nearly impossible. As a result, genuine wasabi is rare even in Japan, and much harder to find abroad.
Imitation wasabi is a food product primarily made from horseradish. It contains added coloring, flavoring, and thickening agents that give it the appearance and taste of real wasabi.
Imitation wasabi, made from horseradish, mustard, and green coloring, became the practical solution. It is affordable, easy to store, and widely available, which has allowed sushi culture to spread and become popular worldwide. Without this substitute, sushi culture might not have grown as quickly outside Japan.
Even in Japan, most wasabi served at conveyor-belt sushi chains or sold in supermarkets is not 100% hon-wasabi (hon means real). There are powdered forms that must be mixed with water, and smooth pastes packaged in tubes. Their compositions vary: some include a small amount of domestically grown wasabi rhizome, others add mustard powder for extra sharpness, and many rely primarily on horseradish. In other words, “imitation wasabi” in Japan exists on a spectrum—from blends with real wasabi to products made almost entirely from substitutes.
By contrast, at high-end sushi restaurants and traditional ryotei in Japan, chefs freshly grate real wasabi rhizomes on sharkskin graters and serve it directly with sushi. These chefs deliberately choose authentic wasabi because it brings out the natural character of the fish and rice. Its fleeting heat, subtle sweetness, and refreshing aroma work in harmony with the sushi rather than overpowering it. In other words, real wasabi is not just a condiment—it is an essential element that allows the true flavor of the ingredients to shine.
In recent years, a few farms in the United States—in places like Oregon, North Carolina, and California—as well as in Europe, China, and other parts of Asia have begun cultivating real wasabi. However, the same challenges remain: it cannot be mass-produced, so supply is very limited.
So while most people around the world—and even many in Japan—have only encountered imitation wasabi, it exists for very practical reasons. And when diners finally taste freshly grated real wasabi, they often discover a surprisingly delicate, even slightly sweet flavor unlike anything they expected.
For travelers visiting Japan, tasting real wasabi at a sushi restaurant or ryotei is a unique culinary experience. It is an opportunity to appreciate the subtlety and harmony of authentic Japanese cuisine—something that cannot be fully replicated elsewhere.
Both sabazushi and battera are types of oshizushi made with mackerel. Oshizushi is made by layering vinegared rice with vinegared mackerel and shiro-ita konbu, then pressing the mixture into a wooden mold. Mackerel has been abundant in Japan since ancient times, which led to the development of this dish as a practical preserved food.
There are clear differences between Sabazushi and Battera, so let us explain them.
The appearance of sabazushi
Sabazushi is said to have originated in the Edo period. Mackerel is salted and transported from its place of origin in Wakasa to Kyoto, where it arrives after 2 to 3 days, by which time the seasoning is just right. This salted mackerel is used to make Sabazushi. Even today, with the development of refrigeration technology, it remains popular with many people and is also a local dish of Kyoto. There are also long-established sushi restaurants that have been in business for generations. Additionally, Sabazushi can be found in other regions such as Hyogo, Hiroshima, and Wakayama, which have adopted the dish from Kyoto.
Sabazushi is prepared using a unique method. First, the air is removed from the vinegared rice to extend its shelf life. Then, the vinegar-marinated mackerel is formed into sticks with a cloth or bamboo mat. Finally, shiroita konbu or rausu konbu is placed on top to prevent the mackerel from drying out. Only half of the mackerel is used so that the thickness of the flesh is evident. The cross-section is rounded, which is why it is also called bozushi (bo means “stick”).
The appearance of battera
Next, Battera is a type of Oshizushi made by placing thinly sliced mackerel marinated in vinegar and shiroita konbu simmered in sweet vinegar on top of vinegared rice. It is typically shaped using a square mold. The mackerel is cut with a knife to minimize waste, resulting in an almost uniform thickness.
Battera is said to have been invented in 1894 by Tsunekichi Naka, the founder of Sushi Tsune, a sushi restaurant in Osaka. At the time, Sushi Tsune was selling Oshizushi made with Konishiro (Gizzard Shad), which was commonly caught in Osaka Bay. Due to its popularity, the traditional method using a cloth became insufficient for production, so a wooden, boat-shaped mold was used instead.
Customers reportedly referred to the mold as “bateira,” a Portuguese word meaning “boat,” which evolved into “battella.” Over time, this name further transformed into “Battera.” As the price of Konishiro (Gizzard Shad) rose, mackerel was adopted as an alternative, and due to its ease of shaping, square molds became the standard.
In summary,
Sabazushi: Use a bamboo mat to shape the fish into a round form, using thick slices of mackerel left whole. The cross-section has a rounded shape.
Battera: Shaped into a square using a wooden mold, thinly sliced mackerel is arranged evenly. The cross-section is square.
Sabazushi is a traditional regional sushi centered around Kyoto, while Battera is a type of sushi that became popular among the general public in Osaka.
This is what most people think of when they hear the word chirashizushi.
Recently, I came across an image on social media of Barachirashizushi made by an American sushi chef. I was surprised to see that Barachirashizushi, a dish traditionally made only by a few sushi restaurants that uphold the Edomae-style, had been created by a sushi chef outside Japan. However, it was labeled as Chirashizushi, which I found disappointing, so I will explain the difference.
The term “chirashizushi” (or “chirashi sushi”) originates from the act of scattering various ingredients over or within vinegared rice and is sometimes referred to simply as “chirashi.” Generally, “Gomokuzushi” refers to vinegared rice mixed with ingredients, while “chirashizushi” refers to vinegared rice topped with arranged ingredients. However, these terms are not strictly distinguished. The names may vary depending on the region (e.g., Kanto or Kansai) and generation.
First, let’s explore the origin of chirashizushi. The term “barazushi” appears here, but it is different from barachirashizushi.
Barazushi, a type of sushi from Okayama, is said to date back to the early Edo period. At that time, the feudal lord of Okayama Domain, Ikeda Mitsumasa (1609–1682), promoted frugality and simplicity. He issued the “One Soup, One Side Dish Edict,” which restricted side dishes to one item other than soup.
They finely chopped ingredients such as simmered shiitake mushrooms, kanpyo (dried gourd strips), and carrots and secretly mixed them into the rice. According to one story, sushi ingredients were placed at the bottom of a box and covered with seasoned rice to disguise them as a simple meal. The box was then flipped over just before serving.
As “Barazushi” spread throughout Japan, a style of scattering the ingredients on top of the vinegared rice rather than mixing them in was developed, and this became known as “Chirashizushi.”
Now, let’s look at the difference between chirashizushi and barachirashizushi, focusing on the names used in sushi restaurants in Tokyo.
The appearance of Chirashizushi
In Tokyo sushi, specifically Edomae sushi, Chirasushizushi refers to a dish where sushi toppings used for Nigiri sushi are arranged on top of vinegared rice (also known as Namachirashi, Fukiyosechirashi, or Edomaechirashi). However, in regions outside the Tokyo area, Chirashizushi generally refers to a dish where seasoned ingredients are mixed into vinegared rice and decorated with shredded omelette and seaweed (also known as Gomokuzushi or Barazsuhi). This is just my personal opinion, but I think that even in Tokyo, the latter is called chirashizushi.
Dishes made with plain white rice rather than vinegared rice are generally called seafood bowls. Sushi restaurants do not serve bowls of plain white rice (they cannot), but some restaurants call dishes made with vinegared rice seafood bowls. In my personal opinion, most seafood bowls served outside of sushi restaurants are made with plain white rice.
The appearance of Barachirashizushi
Additionally, a dish with randomly arranged sushi toppings on vinegared rice is called “barachirashizushi.” Some traditional sushi restaurants in Tokyo offer two types: chirashizushi, which is primarily served in-store, and barachirashizushi, which excludes toppings that are not suitable for takeout and can be taken home.
Incidentally, chirashizushi made with sushi ingredients is not typically prepared in Kanto-style households. More precisely, it may include decorative toppings such as ikura (salmon roe), tobiko (flying fish roe), and steamed shrimp; however, the standard ingredients are dried shiitake mushrooms, lotus root, carrots, snow peas, and shredded omelet.
The freezer compartment of a household freezer typically operates at -18°C. However, in practice, due to factors such as how often the door is opened and closed, the temperature often only reaches around -12°C. While this is cold enough to freeze water, it does not freeze the core of the food, so it may appear frozen at first glance. Proteins, enzymes, and lipids remain unfrozen, causing the taste and texture of the food to deteriorate significantly within a few weeks.
On the other hand, ultra-low temperature freezing can freeze all the components of fish meat, suppressing protein decomposition and stopping lipid oxidation. This makes it possible to store food for up to six months. All living organisms begin to age and deteriorate after death, eventually leading to oxidation and decay. The temperature that can stop this process is the world of ultra-low temperature freezing at -42°C.
Inhibition of enzymatic protein degradation
Under normal conditions, proteins that have ceased activity at room temperature undergo enzymatic degradation. For example, the proteins in freshly caught fish are in a high-molecular-weight state. Through enzymatic degradation, they break down into lower-molecular-weight compounds, advancing the aging process. If this process progresses too far, decay occurs.
Additionally, fish have a high water content of 70%, making them age much faster than livestock meat. Therefore, the key is to quickly cool the fish to ultra-low temperatures after catching them and then thaw them while maintaining the aging process.
Inhibition of fat oxidation
What is commonly referred to as “freezer burn” occurs when the fat naturally present in food rises to the surface and oxidizes, causing the color to turn yellowish and the appearance and taste to deteriorate. To prevent this, it is essential to prevent the food from coming into contact with air. Furthermore, by storing it in an ultra-low temperature environment, the oxidation process itself can be almost completely halted.
Inhibition of microbial proliferation
Even at the -18°C environment of a household freezer, microbial proliferation can be largely suppressed. However, for complete inhibition of all types of microbial growth, ultra-low temperatures are ideal.
Real-world applications
Ultra-low temperature freezing is already widely used in the seafood industry. At Tokyo’s Toyosu Market, premium tuna is stored and transported at -60°C to preserve its deep red color, fatty texture, and fresh taste for overseas shipments. In Hokkaido, Pacific saury is frozen at -50°C immediately after being caught on specialized vessels, allowing them to be enjoyed months later with near-fresh quality. Some Japanese supermarket chains use -45°C freezing for salmon fillets, enabling them to offer sashimi-grade products all year round while minimizing quality loss.
In sushi restaurants, anago (saltwater eel) is often purchased in bulk when prices are stable, stored at ultra-low temperatures, and thawed to maintain quality and cost efficiency. Likewise, ikura (salmon roe) is typically prepared in autumn, its peak season, and frozen for year-round use, ensuring consistent flavor and texture regardless of the season.
The fact that a 10,000-year-old mammoth excavated from Siberian permafrost was still edible after being cooked is a testament to the capabilities of ultra-low temperatures.
Besides anago, nitsume is brushed onto sushi toppings that have been simmered in a flavorful liquid, like shako and hamaguri.
In Japanese culinary terms, “nitsumeru” (verb) refers to the process of reducing the liquid content of a sauce containing seasonings by boiling off the moisture, thereby concentrating the flavor and increasing its thickness. Both “eel sauce” and “conger eel nitsume” are sauces made by reducing the liquid content through boiling.
First, you need to understand the difference between eel and conger eel.
In Japanese, the word “unagi” generally refers to a freshwater eel. The scientific name is Anguilla japonica Temminck & Schlegel, 1846. On the other hand, the word “anago” generally refers to the conger eel. Its scientific name is Conger myriaster (Brevoort, 1856).
While both eel sauce and conger eel nitsume are made by reducing liquid through boiling (the process known as nitsumeru), only the latter is traditionally referred to as “nitsume” in sushi restaurants.
So, what is the fundamental difference between them?
Eel sauce (known as unagi sauce or unagi no tare) is a rich, sweet soy sauce-based sauce that is ideal as a dip or drizzling sauce. It does not actually contain any eel ingredients, but it is a sweet, sticky sauce that is perfect as a topping for sushi rolls and other dishes.
“Eel sauce” can refer broadly to both mass-produced sauces and artisan sauces made by eel restaurants. The basic method for making eel sauce is to mix mirin and soy sauce and heat it. Various ingredients such as sake, sugar, tamari soy sauce, water amber, honey, dashi, and potato starch (commercial products often contain thickening agents) are added to create a unique flavor.
Incidentally, most traditional eel restaurants make their eel sauce using only high-quality mirin and soy sauce. This gives the eel a beautiful glaze and subtle sweetness when grilled, as well as a clean aftertaste, which is why it is considered a craftsmanship.
When making kabayaki, the process of applying eel sauce is repeated multiple times. The components of the eel sauce combine with the umami of the eel to create a deeper, more complex flavor. In addition, applying the sauce and grilling it causes chemical reactions such as the Maillard reaction and caramelization, which further enhance the appetizing flavor.
While you can easily buy eel sauce at the market, it’s incredibly easy and tasty to make at home. Eel sauce can be used as a seasoning for other dishes if there is any left over, but it is primarily a sauce specifically made for making kabayaki. By the way, kabayaki is a fish dish where the long-bodied fish is filleted, the central bone removed, skewered, grilled, and then coated with a thick sauce before being grilled again. In Japan, when people say “kabayaki,” they are usually referring to “unagi kabayaki.” Other ingredients used include hamo and anago.
Nitsume is brushed onto nigiri sushi made with anago, shako, shellfish, and other toppings. In sushi restaurants, it is often abbreviated as “tsume.” There are several methods for making nitsume, including reducing the cooking liquid from simmered conger eel, or simmering the head and bones of conger eel to extract the broth, then adding seasonings and reducing it further. In other words, nitsume contains components of conger eel.
Compared to anago, unagi is more flavorful, fatter, and meatier. Moreover, unagi is considered a higher-quality delicacy in Japan and is therefore more expensive. In terms of taste, unagi has a richer, more intense umami flavor. The common opinion is that anago, because of its lighter taste, harmonises better with soured sushi rice and is therefore the preferred choice for making nigiri sushi.
As a side note, while nigiri sushi with eel is common in the Kansai region, eel is not used as a sushi topping in Edomae sushi. Therefore, Edomae sushi restaurants do not serve unagi nitsume.
In summary, unagi (eel) sauce is made by eel restaurants, while anago (conger eel) nitsume is made by sushi restaurants. Eel sauce does not contain eel components, while conger eel nitsume contains conger eel components.
Cod has long been an important source of nutrition for mankind. The European culture of cod has a particularly long history, and it is no exaggeration to say that Atlantic Cod has supported European civilization for more than 1,000 years. Salted and dried cod have been used as a high-quality preserved food in every country since ancient times and has supported human history.
Bacalao is dried, salted cod, and is a national dish of Spain, Portugal, and other countries.
One reason for the development of dried fish is that there were good fishing grounds in Iceland, the Arctic Ocean, and the continental shelf of North America, far from the major consumption areas of Europe. Another reason is that cod is difficult to distribute in its raw form, so it is difficult to control freshness. Because it loses its freshness so quickly, cod has historically been distributed either as a very salty salted product or as dried fish that has been dried like sticks. Humans have used the wisdom of preservation and endured hunger for various foods. Cod is just one example of the history of dry food.
First, we would like to begin by identifying what we mean by dry food or dried fish.
Dried foods are not simply raw seafood, vegetables, wild vegetables, or other foods that have had the water removed from them, but are better described as foods that have been exposed to the sun’s energy, which changes the ingredients in the food and adds further value to it. he effects of the sun’s energy are significant, generating the power to sterilize, bleach, preserve, and amplify umami, aroma, vitamins, and many other nutrients.
Food deteriorates and spoils over time. This is due to the action of enzymes and microorganisms contained in the food, oxidation, and other factors. Enzymes and microorganisms generally become less active when the moisture content of the food is below 40%, and almost dormant at 15% or less. Furthermore, when the moisture content falls below 10%, most changes induced by enzymes and microorganisms cease. In other words, by drying food to remove moisture, enzymes, and microorganisms stop working, and food deterioration and spoilage are less likely to occur, thus increasing shelf life. So, dried food is the best preservative food that has a shelf life while keeping the umami of the food locked in.
In Japan, dried food is used as a generic term for foods that have been dried. On the other hand, dried fish refers to dried seafood. This is not a mistake, as dried food also includes dried fish and shellfish, but the line between dried food and dried fish is difficult to draw.
Some classify dried food as that which has been completely drained of water and can be stored at room temperature and dried seafood as that which has only been moderately drained of water to bring out the flavor of the ingredients and needs to be kept refrigerated.
There is also a classification of dried food as that in which the salt content in the ingredients is low, and dried fish as that in which the salt content in the ingredients is high.
Dried foods include foods other than seafood, such as dried meat, dried vegetables, and dried fruits, but this section will mainly discuss dried foods only.
Dried fish was originally processed to preserve large numbers of fish caught at one time when freezing technology had not yet been developed. Dried fish has a long history in Japan, and some books indicate that there were several dried fish stores in Kyoto during the Heian period (794-1185). The history of dried fish is said to be more than 10,000 years old.
Now, let us try to classify dried fish according to the different ways of drying.
Shioboshi (塩干し)
The appearance of Maruboshi
Shioboshi is a fish soaked in salt water and then dried in the sun or by machine. There are two types of Shioboshi: Maruboshi, which is dried as it is, and Hirakiboshi, which is dried after removing the entrails.
Suboshi (素干し)
Suboshi is a dried fish or shellfish that has been dried without seasoning.
Niboshi (煮干し)
Niboshi is a dried fish made by boiling the raw fish in salted water and then drying it. Typical examples are anchovies and other sardines, which are used for cooking broth or made into chirimenjako (dried sardines). It is low in fat and has few peculiarities, so it can be used to make dashi that has an elegant and sweet taste.
Yakiboshi (焼き干し)
Yakiboshi is a dried fish that has had its entrails removed, roasted over a charcoal fire, and dried. Unlike Niboshi, which are dried after boiling, yakiboshi does not lose any of its flavor and is said to produce a pure and rich broth. The most famous type of Yakiboshi is Ago (Flying fish yakiboshi).
Chomiboshi (調味干し)
The appearance of Milinboshi
Chomiboshi is a dried fish that is seasoned by soaking the raw fish in a seasoning solution during the manufacturing process. Mirinboshi is the most common type of Chomiboshi, which is soaked in a mixture of soy sauce, sugar, mirin, and other seasonings before being dried.
Bunkaboshi (文化干し)
Bunkaboshi is a dried fish made by wrapping the raw fish in cellophane, which allows humidity to pass through, and drying it with moisture absorbent material. The name Bunkaboshi was given to this new drying method as an alternative to sun-drying.
Haiboshi (灰干し)
Haiboshi is made by covering the raw fish with a special film that allows humidity to pass through and then covering it with volcanic ash to absorb moisture. Haiboshi does not expose the fish to air in the volcanic ash, and takes a long time to remove water and excess fat, so the fish is not oxidized, resulting in dried fish with little odor.
Kooriboshi (凍干し)
Kooriboshi is a dried fish made by repeatedly freezing and thawing the raw seafood to remove its water content. This process was born in northern Japan, where winters are severely cold.
Kunsei (燻製)
Kunsei is a dried fish made by heating finely ground wood and using heat and smoke to seafood. The result is a dried fish with a unique flavor. Smoked salmon is famous worldwide.
Fushi (節)
Fushi is a fish that is smoked with heat and smoke from burning wood and dried until hard. It is used mainly to make soup stock for cooking, such as dried bonito flakes.
Types of fish used for dried fish
The following fish are raw materials for dried fish.
If the purpose is only to preserve fish, it is better to remove a lot of water. The fish is not only preserved, but the water content is adjusted for texture and flavor, and in addition, proteolytic enzymes in the fish tissue work to produce new free amino acids, increasing the taste. This, we feel, is the very preparation of sushi toppings. The preparation of Edomae sushi has evolved from a sort of the certain struggle of preserving fish as much as possible. We can’t help but think that the know-how of making dried fish is utilized in this process.
First of all, the most common argument goes something like this.
Some say that farm-raised fish are fatty, but the image of natural fish being superior has simply taken hold. Others say that farm-raised fish are raised in small fish ponds, so they are less active and less chewy, or that feeding them formula feed harms the taste and aroma of their meat. Well, all opinions can be said to be right or wrong.
It could be for the following reasons. It does not touch on the quality as well as the quantity of fat. Not all fish farms are small, and there are far more people who prefer soft flesh to chewy flesh. And we know that feed has a big impact, so formula feed has been greatly improved. It is all about the so-called superficial argument.
And as you probably know, there are fish of the same season, same species, and same freshness that are natural but separately not so tasty. It can be said that the natural one is the one that is more hit or miss.
And, as a wild guess, I would say that most people only know what farm-raised fish tastes like. In Japan, about 60% of Japanese amberjack (Buri), 80% of Red seabream (Tai), and 99% of Japanese eel (Unagi) are farm-raised. In other words, most Japanese likely eat farmed fish for these three species. The situation is similar around the world. Farmed salmon surpassed the catch of wild salmon in 1996, and currently accounts for more than 70% of total production.
This is the prerequisite for the answer so far. We then look impartially at the facts alone to come up with an answer.
It is not difficult for a person with common sense to compare farmed hamachi and wild buri and recognize them. However, for those who have only eaten Hamachi and usually find it tasty, it may take some time to come to feel that Buri is tasty because their brain has a sense that such food is tasty. Modern people who find foods with amino acids and artificial sweeteners tasty command their brains to tell them that they are not tasty without them. When we become accustomed to foods that mask the original taste, we lose sight of the original taste. This is the true nature of convenient food. Therefore, when a fair comparison of natural Buri and cultured Hamachi Sashimi is conducted, more than 80% of people say that cultured Hamachi tastes better.
Fish have different flavors and aromas depending on where they are caught, and once you understand this, you can narrow it down considerably to the place of origin. The factors are the marine environment in which they live and the type of food they have been raised on. Natural fish can choose the food they eat, and those raised on such food have their original flavor. Fish raised in aquaculture are fed a diet that suits their needs because the emphasis is on economics. Because farm-raised fish cannot eat the food they prefer, they can’t develop their original flavors.
Nowadays, farm-raised eels dominate the eel market, and there is not a mere shadow of the natural product to be seen. Whenever we eat wild-caught eel, we always feel that farm-raised eel does not have the smell of earth and mud from the fat condensed in the skin and meat like wild-caught eel. Whether you like this smell or not, it is the original flavor of the eel. As for the quality of fat, farm-raised eel is not so bad when it is hot, but when it cools down, it feels heavy. Compared with farm-raised eel, natural eel is fatty but gives the impression of being light and smooth, which is why it has been called a specialty.
The iodine value is a number that indicates the degree of saturation or unsaturation of fat and oil. The higher this number is, the higher the content of unsaturated fatty acids and the worse the aftertaste tends to be. For example, farm-raised eel has an iodine value of 150, while wild eel has an iodine value of about 80, and contains almost no unsaturated fatty acids. Unsaturated fatty acids are abundant in Pacific saury (Sanma), Japanese sardine (Iwashi), Mackerel (Saba), etc. In short, these fish and farm-raised fish that eat food made from highly unsaturated acids will all have highly unsaturated acidic constitutions and will have a bad aftertaste. Moreover, if the fat is too strong, the fish will not even develop the aroma of the individual fish. This is one aspect of farmed fish.
Red seabream (Tai) is also available in both wild and cultured forms, but the amino acid composition and flavor compounds in both types do not vary much. Why, then, is there such a difference in taste? The only reason is the difference in flavor. The trace amount of aromatic substances in the fat of sea bream determines the original flavor of the fish. As mentioned above, farm-raised Red seabream does not have the same flavor. The question is whether the aroma is good for us or not. Of course, everyone has his or her taste in aroma. But that is where the value of the food is born. The top chefs are very particular about aroma, and they all use natural ones.
Finally, can you imagine what the results would be if you ate farmed Atlantic salmon and wild Atlantic salmon as sashimi? Probably, the farmed salmon would be superior because of its tender meat, appetizing color, and fat content (we could not find such experimental data, so this is speculation). However, what would be the result of making Nigiri sushi? The noble aroma that nature possesses is irreplaceable. In sushi, where the main focus is on enjoying the aroma, the difference is obvious.
The difference between natural and farmed fish is obvious, as the best sushi chefs never use farmed fish. The exception to this is when the fish is raised in an almost natural environment, without artificial food, so that it simply cannot escape.
All in all, the conclusion is that wild fish tastes better.
