Sushi Ingredients | Sushiblog－Sushiuniversity

Why are two pieces of nigiri sushi made at once?

Have you ordered Nigiri sushi and been served two pieces on one plate?

A photo of Conveyor belt sushi — One plate has two pieces of nigiri sushi.

This isn’t something that happens at a conveyor belt sushi restaurant. It can happen at a sushi restaurant with a counter.

There are multiple theories as to the reason for this, but the most likely one is as follows.

The reason sushi is served in sets of two pieces is that this practice is left over from long ago (the Edo period), when pieces of sushi were made large, like onigiri, and difficult to eat. At some point (it’s unclear when), these were just cut in half, making two pieces that led to what we see today (there are multiple theories about when this happened).

However nowadays, if you were to eat two pieces of each topping, you won’t be able to enjoy as many different kinds, so customers sitting at the counter are served only one piece at a time. So then why do other restaurants continue to prepare two pieces at once? This may be in order to improve the efficiency of the sushi chef’s work. Also, regular customers may see toppings others are ordering and ask for the same one. This helps reduce the workload of the sushi chef.

But there are also some toppings that are better to eat in pairs.

For example, conger eel tastes completely different when one piece is eaten with salt and the other seasoned with sweet sauce. Serving the part of the eel closer to the head skin-up and the part closer to the tail belly-up also offers different textures; skin-up offers a smooth texture while belly-up offers a fluffy texture. In addition, the head and tail simply taste differently. Since the back and belly of fish like bonito and mackerel have different fat content, it can be better to order two pieces at a time in order to fully experience each of the individual qualities of the fish.

The sushi chefs at your favorite restaurant know your preferences well. Depending on the type of fish, they may serve you two pieces of the back side, which has a more fishy flavor, without saying anything.

We hope this information will be helpful.

Revision date: May 29, 2025

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Why don’t I notice the fishy smell in sushi restaurants?

Many overseas visitors who are not accustomed to eating fish often find the fishy smell off-putting. This odor is mainly caused by a compound called trimethylamine, which forms when bacteria break down trimethylamine oxide, a substance abundant in fish that contributes to umami flavor. As time passes, ammonia is also generated, further intensifying the odor.

Trimethylamine begins to form after the fish dies. Therefore, the key to minimizing this smell is to process the fish as soon as possible after it is caught. Removing the slimy coating on the skin, as well as any decaying internal organs or blood, also helps reduce odor. It is essential to rinse the fish with water.

After cleaning, the fish is typically lightly salted and refrigerated. After some time, the salt is rinsed off using saltwater with a salinity of about 3%, similar to that of seawater. This step is crucial because rinsing with fresh water would cause the fish to reabsorb moisture through osmosis, making the previous dehydration process ineffective and leaving the fish with a watery texture.

Bacterial growth is further suppressed by refrigeration, which is why sushi toppings are kept cold. Additionally, since trimethylamine is alkaline, it can be neutralized by vinegar, which is acidic. Soaking fish in vinegar not only helps eliminate odor but also reduces surface bacteria.

In short, sushi restaurants take meticulous steps to prevent bacterial growth and eliminate fishy smells, ensuring that customers enjoy fresh, clean-tasting sushi.

We hope this information will be helpful.

Revision date: June 10, 2025

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Why is sushi with tuna topping so expensive?

A purchase of raw tuna costs at least JPY 30,000 per kilogram. Furthermore, good tuna is judged not only by taste, but appearance is also highly regarded.

The surface is gradually oxidized by letting it sleep (mature) and the sushi chef makes sure that parts are cut of as they change color, when the timing is perfect for both the taste and appearance. In other words, skin is taken from the freshly purchased tuna, the meat of the fish darkened by blood (the blackened area that can’t be used as sushi toppings) is removed, the parts that have changed color are shaved off and then only the remaining, best parts used as toppings are left.

This is why the price is high.

Tuna was not a premium fish during the Edo period!?

A painting depicting the large tuna catch during the Edo period

After the Kamakura period, it was said that “the sound of the voice calling “shibi” sounds like the day of death, which is ominous,” and when power was passed to the samurai, the word “shibi” became associated with “day of death,” and if a tuna lost its life in battle, it was avoided by the samurai as a good luck charm.

Tuna was mainly caught off the coast of Choshi, and was transported to Edo by boat, then placed on a cart and transported through the city of Edo, hidden by straw mats and covered with water. Tuna is large, and the fact that they looked exactly like Dozaemon, who had been drowned, was one of the reasons they were disliked. The fat in particular spoiled quickly, falling apart, and had a strong odor.

At this time there was no ice, so tuna had to be salted. It was cut into blocks, salt was spread all over and in it, and that was it. At Uogashi (the market before Tsukiji), it was treated at shops that specialized in salting fish. The dark, discolored, salty chunks of flesh really were nothing but “Gezakana”.

Gezakana －Relatively low-cost sushi ingredients, such as gizzard shad and horse mackerel. Bluefin tuna used to be also called gezakana in the Edo period, for losing its freshness easily.

This is why they were treated as a lower-class fish, but something changed around 1804-1818. At that time, soy sauce was widely used in the Kanto region, especially in Choshi, so a preservation technique was devised in which fillets of tuna were marinated in salty soy sauce and delivered safely while still raw. Needless to say, this is what we call today’s Zuke. This encounter with soy sauce helped to popularize tuna in the Edo period.

Tuna is originally caught in the open sea. However, due to some tidal current or abnormal weather, an incident occurred where large numbers of tuna were caught in nearby waters. This happened in 1832. It is said that as many as 10,000 were caught in one day. Because so many were caught, it spread, and Edo city was overflowing with tuna. Fresher tuna began arriving in Edo than before.

Around 1810, a new type of sushi was invented in Edo by Hanaya Yohei, in which fish fillets were sold on vinegared rice. Unlike traditional sushi that is fermented (such as narezushi), Kohei’s sushi is made by placing fish meat marinated in soy sauce on top of vinegared rice.

This fast-serving style marked the birth of modern edomae sushi and helped elevate tuna from gezakana to a prized topping in Japanese cuisine.

What makes a good sushi chef?

The balance between Shari (vinegar rice) and the topping is important in sushi. No matter how good the topping, the sushi won’t be good if the Shari isn’t right for it. More restaurants have been using red vinegar lately, but even if you use a Shari with a strong taste like red vinegar, the balance will be destroyed if the topping has a weaker flavor. Seasoning that goes well with various toppings that doesn’t stand out too much is ideal.

It works the other way, too. If the Shari is too weak, the sushi won’t be delicious no matter how good the topping. Even if the topping is not premium quality, if the Shari is matched perfectly, the sushi will be perfect. In other words, a good sushi chef is someone who can make sushi with perfectly matching toppings and Shari.

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Revision date: December 18, 2017

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Why do some sushi toppings contain ginger as well as wasabi?

Ginger is used for toppings with a strong, distinct taste and strong fishy smell such as bonito, horse mackerel and sardines. Ginger has the effect of eliminating odors, but be careful not to use too much, as the flavor of the seasoning may overpower the natural taste of the fish. It should be used solely to enhance the umami of the fish.

Additionally, ginger contains components such as “gingerol” and “shogaol,” which have strong antibacterial properties. These components are known to be effective against foodborne pathogens like O-157 and parasites such as anisakis.

Wasabi has a spicy taste and stimulates the senses of taste and smell and works to dull the senses so the fishy smell is not felt, but ginger is effective in actually extinguishing the fishy smell.

Because the effect of wasabi is transient and difficult to sustain, it is not a good match for fish with a peculiar odor in some respects. For this reason, it is often used with white fish that have a lighter flavor.

We hope this information will be helpful.

Revision date: April 21, 2025

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You know toro tuna and akami, but have you heard of the more rare parts of the tuna?

A single bite of the same bluefin tuna differs greatly depending on the part of the fish it came from.

The body of the fish is broadly categorized into the dorsal (back) and the ventral (belly) sides, which taste completely different. Of course the meat near the head tastes completely different from the meat near the tail. If you dig even deeper, there are parts that aren’t as well-known as the Otoro (fatty), Chutoro (medium fatty) and Akami (lean) tuna meats. We’d like to explain those now.

1. Hachinomi or Tsunotoro Nouten

“Hachinomi (ハチの身) or Tsunotoro Nouten” is the meat from the crown of the head. It is fatty and rich and also called “Head Toro”. Only about 1kg of this precious meat can be taken from even a very large fish, and it is only shared with regular, loyal customers.

2. Kamatoro

“Kamatoro (カマトロ)” is taken from behind the jaw. It is known as “shimofuri (霜降り)” or marbled meat. There are no veins in this part so the meat is soft and the marbling is more detailed than Otoro, so it is sticky and melts in your mouth. The balance of fat and sweetness in this part is unparalleled. It can be said that otoro (such as shimofuri and jabara) of tuna is the representative part of toro tuna. This is an image of the shimofuri on the right, and the jabara (蛇腹) on the left.

3. Chiai

“Chiai (血合い)” is the part with the most veins, so it is a dark red color. It has a strong odor of blood and has multiple times the acidity of the lean meat, so it is not used as a sushi topping. Chiai is rich in iron and protein and is considered to be highly nutritious. Recently, it has been discovered that selenonine, an antioxidant found in high concentrations in tuna and mackerel, is effective in preventing lifestyle-related diseases, reducing stress, and promoting anti-aging.

4. Chiai Gishi

“Chiai Gishi (血合いぎし)” －Located right next to chiai, this is the meat you can taste the umami of the rich red meat and the sweetness of toro fat at the same time.

5. Wakaremi

“Wakaremi (分かれ身)” is a precious part with very little meat found next to the dorsal fin. The part especially close to the dorsal fin is popular and called “Setoro (背トロ)”. Setoro has both the umami of akami and the umami of fat. The fat isn’t overbearing so you can eat a ton. However, this part is hard to get, even in high-quality tuna and is not available except to regular customers in almost all sushi restaurants.

6. Tossaki

A sushi chef, Hiroyuki Sato, serves a tossaki hand roll as the first sushi piece of the course. “Tossaki (突先)” is an exclusive cut of tuna that goes well with sushi rice using red vinegar, which is less sour but has more umami and flavor compared with white vinegar. Because tossaki is the base of the tuna’s head and it moves a lot, there are a lot of muscular striations. Therefore it needs to be prepared using the back of a knife carefully as if peeling it off (Hagashi). It is said that tossaki is a high-tuna-flavor cut. A couple of Sato’s apprentices also offer a hand roll to open up the meal in the same way.

7. Tenpa

The meat of tuna gets leaner and muscular striations are fewer towards the inner center of the body. “Tenpa (天端)”, surrounding the spine, is deeper in color and tastes stronger. It features the tender texture coming from the finest meat quality. This is also called Tenmi (天身).

8. Hohoniku

A photo of Hohoniku maguro — The appearance of Hohoniku maguro nigiri

“Hohoniku (ホホ肉)” is cheek meat. The cheek meat of tuna is a rare part of the fish, with only a few hundred grams being taken from a 100kg fish. It is crescent-shaped, with one on either side. It can be taken from not only bluefin tuna, but also bigeye tuna, etc., but if you want to eat it as sashimi or nigiri sushi, you need to be careful about its freshness. Once frozen, it can only be used in dishes where the smell is masked by cooking with garlic, pepper, olive oil, etc.

Its cheek meat is juicy, stringy, and low in fat. When making nigiri sushi, it is often Aburi to soften the stringiness. Aburi enhances the flavor of this part of the fish. And there are almost no sushi restaurants that buy tuna heads or whole fish. Therefore, the only places that can offer this part of the fish are conveyor belt sushi restaurants and izakaya.

9. Hireshita

“Hireshita (ヒレ下)”－Below the “Wakaremi” is a section with white veins intertwined. This is typically used for Tekkamaki. This is because the white veins are tough and take a long time to remove. However, between the veins lies the fatty richness of Otoro and the red meat-like flavor of Chutoro, and carefully removing the veins reveals a delicious part. This truly is the valuable part of whether there will be even enough for 10 pieces of sushi from an over 200 kg tuna. This is written in a sushi manga named by Hiroshi Akiyama of Sushi Kin.

If you are fortunate enough to get an opportunity to taste these, you can take it as proof that you have been accepted as a regular and loyal customer. It is difficult to distinguish these parts by appearance alone, so make sure you try them at a sushi restaurant you can trust. Just for your reference.

Today you will learn how to easily identify artificial salmon roe!

The natural salmon roe season is the autumn. Does this mean that most of the roe eaten during the off-season is artificial Salmon roe. Not necessarily. As stated in his biography, even at the famous sushi restaurant Sukiyabashi Jiro, frozen roe is thawed as necessary.

Long ago this was an extremely expensive topping that ordinary people couldn’t afford, so artificial roe was used. There was a time when this was the case. But nowadays salmon roe is regularly imported from overseas and can be obtained cheaper, eliminating the need to use artificial roe instead.

However, we cannot overlook the commercial law for passing off artificial roe as natural roe. In Japan, the non-perishable properties of artificial salmon roe made from chemical substances (mainly sodium alginate) is utilized and used mainly in hospitals, but not sold to the general public. I’ll also tell you that it is very rare to find a sushi restaurant that serves artificial roe. Cheap roe is generally made from eggs of trout, other related species, or imported from Canada and other countries.

Unfortunately I’m not familiar with the state of things outside of Japan, but I can tell you how to tell the difference. All it takes is hot water and a moment of observation. Artificial salmon roe will show no changes in hot water, but natural roe will start to turn white on the surface. This is due to the protein reacting and changing with the heat. That said, this is not an experience you can just set up at the sushi restaurant.

The following describes the artificial salmon roe composition. The nucleus of artificial salmon roe is made of red-colored vegetable oil, the thin outer film is made of sodium alginate or carrageenan, and the sol-like contents are made of polysaccharides derived from seaweed, Gum arabic, and Xanthan gum. While real salmon roe is high in polyunsaturated fatty acids, artificial salmon roe is high in saturated fatty acids derived from vegetable oils, oleic acid and linoleic acid.

As an aside…

What are the fish eggs on sushi called in Japan?

There are eight types of fish eggs served at Japanese sushi restaurants. However, not all of them are used for Nigiri sushi. Some are served as side dishes. Uni is sometimes translated as sea urchin’s roe, but it is actually the sea urchin’s genitals (testes and ovaries). Most people also don’t know that Tobiko and Tarako are not served at 99% of Edo-style restaurants. In other words, these toppings are only served at kaiten-sushi (conveyor belt) restaurants. The one type of roe topping that can probably be found at all sushi restaurants is Ikura. Even more types of fish eggs, such as Masago, Paddlefish roe and Hackleback roe are used in sushi overseas, but Japan remains more conservative. Of course, it’s only natural that fish substitutes are not well-received in the place where sushi was born.

Types of fish roe

Fish roe usually cannot be preserved as is, so it is salted or smoked to make it last longer. Today, thanks to advances in freezing technology, frozen fresh fish roe is also available, but as a raw material for processing, fish roe is often salted to reduce its water content and then frozen for preservation. Nutritional value is generally high in fat and protein and low in carbohydrates, with higher calories and cholesterol than the meat of the parent fish.

What is Ikura? － It is Salmon roe.

What is Kazunoko? － It is Herring roe.

What is Sujiko? － It is Salmon roe that is still within its egg membrane.

A photo of Sujiko — Sujiko’s nigiri sushi is quite unique.

What is Tobiko? － It is Flying fish roe.

What is Tarako? －Tarako is the salted ovary of Alaska pollack. It is often colored red with food coloring. Karashi-mentaiko is Tarako marinated in a seasoning solution of salt and chili peppers, and is a well-known Hakata specialty. The name Karashi-mentaiko comes from the Korean word for Alaska pollack, Mentai.

a photo of Tarako nigiri sushi — Tarako nigiri sushi is very rare, even in conveyor-belt sushi.

What is Caviar? － It is Sturgeon roe.

A photo of caviar — Caviar is not used in Edomae sushi.

What is Karasumi? －It is made by salting, aging, and drying the ovaries of Flathead gray mullet (Bolla).

A photo of Dried mullet roe (Karasumi) — The appearance of Dried mullet roe (Karasumi)

The product resembles Chinese ink karasumi, hence the name. Good ones are candy-colored, cut into thin slices, lightly roasted, and served as nibbles for drinks. Imports have been increasing recently, but the most famous domestic product is karasumi from Nomo, Nagasaki Prefecture.

What is komochi konbu? － It is Herring spawn on kelp.

A photo of Herring spawn on kelp (Komochi konbu) — The appearance of Herring spawn on kelp (Komochi konbu)

What is komaiko? － It is Saffron cod roe.

A photo of Saffron cod roe (Komaiko) gunkan — The appearance of affron cod roe (Komaiko) gunkan

What is Capellinko? － It is Capellin roe.

a photo of Capellinko gunkamaki — Capellinko (Capellin roe) is a substitute for Tobiko (Flyingfish roe).

What is Madarako? － It is Pacific cod roe.

What is Masuko?－ It is Humpback salmon roe.

a photo of Masuko gunkanmaki — In Japan, Humpback salmon roe is called Masuko and Chum salmon roe is called Ikura.

What is Masago? －What’s the difference between Tobiko and Masago?

Just for your own information.

Related contents：

What is Artificial caviar?

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Revision date: December 16, 2024

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Why is sushi eaten with soy sauce (shoyu)?

A photo of soy sauce — A surprising number of tasks in the Edomae style utilize the scientific effects of soy sauce.

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.

A Guide to Avoiding Food Fraud!

It is true that in an age when aquatic resources are being depleted, there is a worldwide demand for a substitute for luxurious fish. However, since it is impossible to distinguish between them when they are cut into pieces, we cannot allow them to do whatever they want.

Global food fraud involving seafood can be classified into the following four patterns. Examples of each are provided below.

1. Fish species mislabeling:
According to an article on DNA testing conducted within the EU in May 2024, samples from approximately 300 restaurants, including those in Brussels, were tested. Despite being labeled as tuna, the survey reported widespread contamination and mislabeling of 15 species, with the species of 15% remaining unidentified.

2. Origin mislabeling:
According to a report published by SeaD Consulting in December 2024, it was revealed that 4 out of 5 shrimp labeled as “Gulf Shrimp” served at the National Shrimp Festival, a national event in Alabama, were actually imported (primarily farmed shrimp from China and Argentina).

3. Farm-raised vs. wild mislabeling:
DNA analysis was conducted on approximately 120 salmon products sold at supermarkets and sushi restaurants around Seattle (2022–2023). The results showed that 18% were mislabeled. Specifically, 32.3% of salmon sold at sushi restaurants were farm-raised but labeled as “wild-caught.”

4. Concealment of chemicals and preservation methods:
In December 2024, the RASFF (Rapid Alert System for Food and Feed) reported that carbon monoxide was detected in multiple tuna products originating from Belgium. In the United States, the FDA has approved CO treatment as a “GRAS” (Generally Recognized as Safe) substance.However, it is banned in many countries, including the EU, Japan, and Canada. In the U.S., “vitamin tuna” (tuna treated for color improvement) is reported to account for up to 60% of the market.

Below are some examples of practices that have been carried out in Japan for many years.

First of all, Opah belly meat with some fat is used for the tuna in Negi-toro (tuna minced with Welsh onion leaves). Opah is widely distributed in warm seas and it’s known to be inexpensive with a smooth taste. The price is less than 1/100 of the Pacific bluefin tuna and if possible Negi-toro made from Opah should be avoided.

Next let’s discuss Japanese conger, an essential Edo-style sushi topping. A substitute for Japanese conger is the Common snake eel, which is a type of sea snake from Peru. The taste is pretty good, but the skin is rubbery and it doesn’t stick to the Shari (vinegar rice) so it’s instantly apparent that it’s a substitute fish. If you find Japanese conger at kaiten-zushi for JPY 100 per plate, you might want to question the source.

A premium sushi topping is the Mirugai clam (also called Hon-miru). This shellfish is characterized by its unique texture and taste. Instead the Japanese geoduck (Shiro-miru) is used, which sells for half the market price. However, the taste of the two is so similar that even Sushi Tsu has mistaken them, which is great news for dishonest dealers.

In April 2015 the Food Labeling Act was revised in Japan, leading to progressive reduction of fraudulent labels, but it is not a solution that eradicates dishonest dealers so consumers need to be educated and aware.

To effectively combat food fraud, regulatory bodies must enforce strict labeling laws and conduct scientific inspections, businesses must maintain transparent traceability and obtain trusted certifications, and consumers must remain vigilant by carefully checking product information, prices, and origins while choosing reliable vendors and asking questions whenever doubts arise.

What is Shiromiru?

https://www.mashed.com/30278/things-never-order-sushi-restaurant/

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Revision date: July 4, 2025

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Is Nigiri sushi made by a Master Really Transparent?!

A photo of shari — There is a moderate amount of space between the grains of rice.

“Sorry to keep you waiting,” says the sushi chef as he places a nigiri sushi in front of you, pieces of rice falling out. You may be served this kind of nigiri sushi at restaurants that have lines out the door. Of course, nigiri sushi that falls apart before it reaches your lips is a no-go.

Good nigiri sushi looks solid, but the rice naturally falls apart when you put it in your mouth. Secondly, the loosened rice absorbs the saliva that has the flavor of the topping, and does not make your mouth sticky.

On the other hand, if the rice is pressed tightly, it does not absorb the saliva. The taste of the toppings continues to linger in your mouth and gradually becomes a nuisance. In short, when they press the sushi, the surface is firmly pressed, but the inside is fluffy. This is the perfect way to press sushi.

At first, they will be too focused on the shape, their fingers will be too tense, and they will be pressing too hard. Once they relax their fingers and get a sense of the subtle pressure, they will be a full-fledged sushi chef. It is said that they should press the shari as if they were wrapping it in air.

For example, shari pressed for gunkanmaki should be hard enough to crumble after being placed on their index finger for five seconds. For nigiri sushi, it should be hard enough to sink a few millimeters when placed on a plate under the weight of the topping.

A master sushi chef is at the next level, and it is said that “nigiri sushi made by a master can be seen through when held up to the light.” He holds the sushi very gently. And it doesn’t lose its shape.

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Revision date: June 13, 2025

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Once you try Kuruma ebi sushi, you’ll never want any other shrimp.

Sushi Shrimp Overview

Shrimp used in sushi is typically evaluated based on six criteria: color, sweetness, umami, aroma, texture, and cost. This evaluation excludes sweet shrimp and botan shrimp, which are eaten raw.

Among shrimp that are cooked—usually by boiling—and served in sushi restaurants, including conveyor belt sushi, the most commonly used are banamei shrimp (farmed), black tiger shrimp (farmed), and kuruma shrimp (wild or farmed).

In Japan, annual shrimp consumption is estimated at around 250,000 tons. Of this, banana shrimp and black tiger shrimp make up approximately 80%, while kuruma shrimp accounts for less than one-tenth of banamei shrimp’s volume.

Banamei Shrimp (Litopenaeus vannamei)

Banamei shrimp is the world’s most widely farmed white shrimp and is commonly used in Japan, especially in conveyor belt sushi and supermarkets.

When cooked, its color shifts from pale pink to a soft orange, creating a clean, uniform appearance ideal for commercial use. Its sweetness is mild and understated, offering a balanced flavor that blends well with vinegared rice.

The umami is gentle and neutral, without any strong distinctive notes, making it a good companion to other ingredients. However, its aroma is weak, especially when cooked without the shell, which is why it’s rarely used in high-end sushi establishments where fragrance is prized.

The texture is soft and slightly moist, particularly after freezing and thawing, making it easy to eat for all ages.

Where banamei shrimp excels is in cost-effectiveness. Its high yield, low price, and ease of processing make it a go-to option for volume-based food service. Though not remarkable in any single aspect, its consistency and affordability make it indispensable for everyday sushi.

Black Tiger Shrimp (Penaeus monodon)

Black tiger shrimp, named for its dark striped shell, is a large species that once dominated global shrimp farming. It remains popular in Japan as a sushi and tempura ingredient, even as banamei shrimp has become more prevalent.

When cooked, it shows a vivid red-orange border contrasting with its white flesh—a striking visual that enhances the presentation of nigiri sushi. This eye-catching appearance makes it popular in local and mid-range sushi restaurants.

It has a slightly richer sweetness than banamei shrimp, paired with moderate umami and a clean, balanced flavor. While its raw aroma is faint, cooking brings out a subtle shrimp-like fragrance that complements the delicate scents of sushi.

Its texture is firm and springy, retaining its structure even after freezing, which makes it suitable for processing. This satisfying chew is one of the reasons it’s favored in sushi preparation.

Although farming costs have risen in recent years, black tiger shrimp still provides solid value as a mid-tier option. It’s more expensive than banamei shrimp but cheaper than kuruma shrimp, making it a practical choice for many sushi restaurants.

Overall, black tiger shrimp strikes a good balance between appearance, taste, and cost—neither luxurious nor cheap, but reliably satisfying.

Kuruma Shrimp (Marsupenaeus japonicus)

Kuruma shrimp is a premium species native to Japan and prized in both sushi and traditional kaiseki cuisine. Its excellence lies not only in its high status but in its culinary balance—color, sweetness, umami, aroma, and texture are all outstanding.

When cooked, it takes on a brilliant orange-red hue with a glossy finish that signals freshness and quality. In its raw state, it has a translucent reddish-brown shell that transforms into a visually stunning centerpiece after boiling—ideal for high-end sushi presentation.

Its sweetness is refined and natural, gradually unfolding with each bite and harmonizing beautifully with sushi rice. Unlike straightforward sugary sweetness, it carries a richness tied to the shrimp’s inherent umami.

That umami deepens when heated, resulting in a pure, well-defined flavor with a clean aftertaste. Expert sushi chefs often grill or steam kuruma shrimp lightly to draw out its full potential.

Its aroma is delicate and marine-like, intensifying when cooked and adding elegance to the dish. The texture is supple yet resilient, with fine muscle fibers that feel smooth on the tongue. Unlike the springy bite of banamei or black tiger shrimp, kuruma shrimp has a calm, refined elasticity—a “quiet luxury” that signals quality from the first bite.

Due to limited domestic production and a focus on wild-caught varieties, it comes at a premium price. Even farmed kuruma shrimp remains significantly more expensive than banamei or black tiger shrimp. As a result, it’s rarely used in conveyor belt sushi and is mostly reserved for upscale restaurants.

In traditional Edomae sushi, kuruma shrimp may be aged in kimizu oboro (sweetened egg vinegar oboro) for several days to enhance its umami and introduce a gentle acidity. Its preparation also requires care—shrimp naturally curl during boiling, so chefs make precise incisions or use skewers to keep them straight, a technique that showcases culinary skill.

In short, kuruma shrimp combines taste, aroma, beauty, and elegance into a single, premium ingredient. Though costly, it brings depth and refinement that elevates sushi to an art form—a true “star” of the sushi counter.

Why is Zuke used for lean meat?

Zuke is one of the traditional Edo-style sushi methods. It is said that it was started in the Edo period to stop tuna from rotting when there were large amounts of the fish in the market. Now that there has been advances in refrigeration technology, it’s no longer necessary, but maturing the fish gives it a completely different taste and brings out its umami. Zuke is divided into two broad methods. Here we describe the characteristics of each.

Recently, most sushi restaurants incorporate the “Single Zuke”.

Each slice of tuna is soaked separately, so it can mature quickly. The immersion time is only a few minutes. The idea is to marinate just enough so that the tuna’s aroma remains and the soy sauce doesn’t overtake it.

On the other hand, the old Edo-style method is to perform Zuke after parboiling.

Parboiling means to wrap the fish in a wet cloth, and poor boiling water on the wrapping until the color of the tuna changes color, then turn the fish over and repeat the process. The fish is then put in ice water so the heat doesn’t go too deep in the meat. It is immediately removed once it cools so that it doesn’t get too watery. The tuna is then put in Zuke soy sauce and left to marinate for about half a day. In this method, the soy sauce only soaks into the surface part where the color changed from the parboiling, so the flavor of the tuna remains.

Both methods keep the maximum tuna flavor possible. Tuna is an essential part of Edo-style sushi. There is great diversity between sushi restaurants in the parts, marinating time and flavor of Zuke, which creates a new, original flavor when the lean meat of the tuna soaks up the soy sauce. The fattiest cuts of tuna are most popular. The lean meat has only become more popular due to a rekindled interest in zuke, but in fact during the peak of the bubble economy, there was a time when high-end restaurants in Ginza didn’t know what to do with all their leftover lean tuna meat. It’s almost unbelievable to think of it now.

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Revision date: August 1, 2017

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What are “Ikejime” and “Nojime”?

How the fish is butchered also changes the taste. If the fish suffers and struggles, the body wears and may be damaged, circulating oxidized blood throughout the body, which makes it lose flavor. For fish of high value such as sea bream, flounder, yellowtail, rudderfish and tuna, a method called “ikejime” is used.

The taste of tuna is said to be determined based on the preparations after being caught. The tuna is caught with as little suffering as possible and the nerves are killed immediately for an instant death. Generally, blood is then drained perfectly, entrails and gills are removed, the tail cut off and then the fish is placed in ice-water to lower the body temperature.

The medulla oblongata and main artery of the fish are cut and a kitchen knife is inserted into the base of the tail to drain the blood. A thin metal rod is inserted into the backbone to paralyze the nerves and at the same time controls the putrefied materials that come out of the spinal cord.

This extends the time until rigor mortis sets in, making it easier to maintain freshness and simultaneously preventing blood from circulating in the body, which also prevents the fishy smell.

Freezing the fish to death in ice water is called “nojime”. This method is generally used for small fish such as sardines, horse mackerel and mackerel that are fished in large volume. Although the freshness of the fish deteriorates more quickly than in the case of “ikejime,” it can be done in large quantities without a lot of labor and maintains a certain level of freshness afterwards.

At fish markets, the term “kill” is not used for living fish, instead the word “shimeru” meaning to close or tighten. The term “dead fish” is also not used. Instead the term “nojime” is used for fish that died naturally en route to the market. This stems from the awe of precious life and turning that life into food.

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Revision date: January 13, 2023

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Best supporting role for wasabi that magnifies the umami in sushi many times over

Back before there were refrigerators, wasabi was indispensable for Nigirizushi, eliminating the fishy smell and also providing bactericidal effects to prevent the fish from spoiling. Wasabi is originally from Japan and it has been used in Edomae sushi from the very beginning. Even with all the advancements in technology for storing sushi toppings, wasabi is still used today to remove the fishy smell and prevent spoiling. However, nowadays the flavor and aroma of wasabi and the way it brings out the flavor of the sushi topping is the main focus.

When wasabi is grated and exposed to the air, its unique heat is made enhanced by enzymes. Using a coarse grater gives the wasabi a rough, fibrous texture that spreads the spicy flavor through to the back of the throat. On the other hand, if Sharkskin wasabi is grated finely, it foams up with tiny bubbles and makes a creamy taste. The type of wasabi depends on the personality of the shop.

However, the powdered wasabi and wasabi paste you find at kaiten-zushi (conveyor belt sushi) is primarily made from horseradish and is colored and scented with additives. It isn’t dried wasabi and it is significantly cheaper.

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Revision date: June 6, 2017

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