Sushibog is wrtten by researchers of SushiUniversity

Do you know the dangers of eating raw tuna?!

Cutting Tuna — Sushi chefs make sushi toppings from tuna.

We would like to examine this challenging title that appears regularly in the media.

This story has not recently come to a boil; in fact, it is already widely known. However, the reason it is a recurring topic is due to the fact that the assumptions between the writer and the reader do not match. The reason for this is that the writer tends to exaggerate a bit in order to get people to read the article. The readers, on the other hand, are overwhelmingly uninformed and are led to feel uneasy about what they hear. Here’s what we guess.

So, in order to explain this issue properly, we will squash any ambiguities.

There are three major risks.

The first is food poisoning due to bacterial growth. The second is food poisoning by parasites. The third is the medium- to long-term effects on the human body of mercury, dioxin, microplastics, and other substances that accumulate in tunas.

a photo of Food poisoning prevention — The best way to prevent food poisoning is to keep hands clean.

We can say that food poisoning caused by bacterial growth is a very rare and serious matter that can affect the survival of a business, if only in sushi restaurants. Here are some data to support this. According to data from the Tokyo Metropolitan Government, the percentage of food poisoning cases occurring at sushi restaurants is less than 0.8% of the total number of food poisoning cases. The data shows that food poisoning rarely occurs at sushi restaurants.

The reasons for this are largely related to soy sauce, salt, and vinegar. First, soy sauce has bacteriostatic properties, and by marinating tunas and other fish in soy sauce, the growth of bacteria is inhibited. Second, salt has a bactericidal effect, killing bacteria on the surface of the fish. Besides, it uses osmosis to expel the rotting components of fish meat, etc. And vinegar also has a sterilizing effect. Since the ㏗ is 2~4, the bacteria are almost killed when they come in contact with vinegar. Sushi chefs put vinegar on their hands or wipe their knives with a cloth dipped in vinegar to sterilize them. Shari is made with vinegar and salt, so it is also sterilized. In other words, more steps are taken to prevent the growth of bacteria than in any other dish.

Next, we will examine food poisoning caused by parasites; Anisakis accounts for 50% of all cases of food poisoning. It can be said that raw seafood always contains parasites, but removing these parasites is the foundation of a sushi restaurant, and Anisakis, which can be visually identified, cannot be overlooked. On July 2, 2021, a method to kill Anisakis with a high current was also announced and will soon be put to practical use.

Also, it totally depends on where you eat. Do you buy it at the supermarket or fish market and eat it at home or a sushi restaurant? Even at the same sushi restaurant, there is a difference. Is it a conveyor-belt sushi restaurant with a chain or an individual restaurant run by a master and his apprentice? In our opinion, however, food poisoning caused by Anisakis has not occurred in private restaurants.

We will examine the medium- and long-term effects of toxic chemicals. First, let’s look at the effects of mercury. For example, the level of effect is naturally different for those who consume tuna every day and those who eat tuna once a week. Although the Japanese eat a lot more tuna than other countries, the effects of mercury accumulated in tuna have not yet been widely discussed. The effects of mercury on the mother’s body are well known, and the following warning is given by the doctor in charge.

In Japan, if you eat more than 160 grams of tuna per week, you need to be careful. Pregnant women do not bother to eat 160 grams of tuna in the first place. In addition, although Kuromaguro (Bluefin tuna), Mebachi (Bigeye tuna), and Minamimaguro (Southern Bluefin tuna) have safe amounts, Kihada (Yellowfin tuna), Binnaga (Albacore), and Mejimaguro (Young bluefin tuna) do not require any restrictions on the amount eaten. Also, there is no need to worry about canned tuna. This is also a well-known story.

And, this may come as a shock to tuna lovers, but it is the toro part of the belly that tends to accumulate the most dioxin, which is considered the best part of the fish. The toro is mostly fat, and dioxin taken in from feed and seawater accumulates there. In nature, the toro portion of tuna is normally about 20% of the tuna meat. However, in fattened tunas, 70~80% of the body is toro. The meat of fattened tuna is a habitat for dioxin. According to some research data, the amount of dioxin accumulated in fattened Kuromaguro was about 2 to 3 times higher than that in wild tuna, and in fattened Minamimaguro, it was about 2 to 10 times higher.

The final section examines microplastics’ medium- and long-term effects on the human body.

In the North Pacific Ocean gyre, famous for the Pacific Garbage Belt, plastic fragments have been found in the digestive tracts of 10%-35% of the fish examined. Many researchers have noted that microplastics are vectors that bridge harmful pollutants to fish and marine life. U.S. health officials estimate that less than 0.3% of microplastics taken into the human body reach the body’s lymphatic and circulatory systems from the gut. And only a very small fraction of these microplastics affect the body’s organs. Still, the effects of microplastics taken into the body on human health are not fully understood.

In 2014, the Ministry of the Environment’s survey on the actual state of marine debris reported that the amount of microplastics in the waters surrounding Japan was 16 times more than in the North Pacific Ocean and 27 times more than in the world’s oceans. And yet, around 2020, major media outlets are only now beginning to report on the issue. Unfortunately, this is one of the topical issues that Japan is still turning a blind eye to. In fact, this is a more serious problem in the world, and we imagine it will be sensationalized soon. We should put some restrictions on countries and companies dumping plastics into the oceans. Japan must be proactive in this regard in order to achieve the SDGs.

In conclusion, we think this title comes from the media’s self-righteousness.

We are not a researcher and cannot say that it is absolutely safe. It is a medium- to long-term issue that should not be neglected with careful monitoring. But in general, Tuna is an expensive food, so it should be economically difficult to consume it in large quantities. Instead, the media should focus on rice, wheat, corn, and other foods that are consumed daily. For your information.

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Revision date: September 8, 2023

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What is traditional Ikejime?

a photo of Ikejime Madai — In order to fully drain the blood from the red seabream, the spinal cord at the base of the tail is also cut off.

Articles related to Sushi are now filled with jargon such as Shinkeijime, Chinuki, Noujime, Ikekoshi, and Korijime. That much confirms the fact that opportunities to eat fish are increasing all over the world. And it has also become a common occurrence to find articles written by people who have heard Ikejime in bits and pieces. According to what we have heard, Ikejime processing is one of the reasons why red seabream from Akashi, which is said to be the best in Japan, is so tasty, and the technology has been around since the Edo period (1603-1868).

The Ikejime procedure consists of four parts or some of them, and the point of Ikejime is to kill the fish in a relaxed state.

The first step is a brain-dead the fish by stabbing it in the head with a sharp object. This process is called Noujime (Nou means brain and jime means kill).

After the fish is out of the water and before it gets out of control, it is stabbed in the head with a hook called a Tegaki (手鉤). If the brain is not destroyed by one blow, the fish will struggle. When this happens, a large amount of ATP, which is the source of umami, is consumed. As a point of caution, the right side of the head is stabbed so that the puncture wound is not on the upper side, as the fish will be handled later in the distribution process with the belly facing forward and the head facing to the left.

Next, use a knife to quickly kill the live fish.

Place the fish with its head facing left, open the gill cover, and cut a spinal cord below the lateral line that is visible on the fish’s body. Since bones have hard parts, move the cutting edge slightly to the left and right if it is difficult to cut. If you don’t cut it completely, you have not killed the fish, and the blood will not drain well. To drain the blood sufficiently, the spinal cord at the base of the tail is also cut off. Place the fish’s head to the right and cut the front part of the tail so that the spinal cord is visible. At this point, the knife should be placed at a right angle to the spinal cord so that the cut surface is not at an angle.

The next step is to remove the nerves and delay rigor mortis. This process is called Shinkeijime (Shinkei means nerve).

Shinkeijime is a technique to delay rigor mortis in fish. A wire is inserted into a small hole in the upper part of the spinal cord. When the wire hits the nerve, the fish will act violently, so hold it down. The nerve hole tapers from the head side to the tail, so when stabbing in from the tail side, make sure to insert the wire securely first, so that the wire does not pierce through the nerve hole and pierce the body. Once you have securely inserted the wire, repeatedly pull out and insert the wire to completely destroy the nerve in the hole. When the nerve is destroyed, the body color quickly changes to white. The destroyed nerve appears as a white, sludgy fluid.

Any wire can be used for this purpose as long as it is straight, but a piano wire that does not bend easily can be used many times. The diameter of the nerve hole differs depending on the fish. Use a thick wire for Tai and Suzuki, which have large nerve holes, and a thin wire for Aji and Anago, which have small nerve holes. Several types between 0.8mm and 1.5mm should be enough. As you get used to it, you will be able to stick the wire in without visually seeing the nerve hole. If you remove a few scales from the upper part in front of the tail, insert the wire along the spinal cord, probe the nerve hole, pierce it, and destroy it, you can remove the nerve without making any cuts on the fish’s body. The same applies to the head side. The nerve hole is probed and pierced from the head side, but the key is to keep the head and body straight so that the nerve hole is not misaligned by the spinal cord severed behind the gills. In any case, it takes experience and familiarity to pierce the nerve hole without seeing it.

The final step is to perfectly remove the blood from the fish’s body. In Japanese, it is called Chinuki (Chi means blood and nuki means remove).

The blood is removed by cutting the spinal cord and immersing the fish’s body in seawater. At this time, running water is more reliable to remove blood. In the case of stored water, leave it for a while and then replace it with other stored water. If the water does not turn red with blood, the fish has already been drained. Blood has a tendency to clot, so it is important to wash off any blood that has clotted on the gills or other parts of the body. The body temperature of the fish is raised by the Ikejime process and by human hands. Since the fish were originally in the sea, which has a lower temperature range than that of the ground, the higher temperature increases the speed of deterioration, so the fish is soaked in ice water to lower the temperature of the fish’s body. If the fish is soaked too long, its body surface will turn white, so remove it from the water when it cools down.

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Revision date: August 18, 2023

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Authentic sushi toppings only eaten in Tokyo!

a photo of making nigiri sushi — A sushi chef adds wasabi to sushi topping.

Sushi continues to spread throughout the world. Nowadays, not only sushi rolls but also Nigiri sushi can be eaten all over the world. But if you have the opportunity to come to Tokyo, we want you to go home with sushi toppings that you can only eat in Tokyo. Not seafood exported from your country, but sushi made from natural seafood caught in the seas around Japan.

First of all, what kind of sushi do you think of when you hear the word “Nigiri sushi”? Most people think of sushi with Hamachi or Salmon on top of vinegared rice.

This is correct if you only look at the appearance. However, from the essence of Nigiri sushi, it is clearly wrong. In order to make your understanding perfect, we dare to confuse you, but we would like to understand the term “Edomae sushi” as well.

What is Edomae sushi?

Nigiri sushi and Nigiri are words you may have heard before. However, “Edomae sushi” is a word you may not be familiar with, so it is important to understand exactly what it is.

It is quite simple.

Edomae sushi consists of Nigiri sushi and Nori maki. Nigiri sushi originated in Edo (now Tokyo) about 200 years ago, while Nori maki is said to have originated 50 years earlier. And Edomae sushi has remained almost in its original form to the present day. We will skip the explanation of Nori maki here, so you can just assume that “Edomae sushi” and “Nigiri sushi” refer to the same thing.

Now let’s dig deeper into the story of Nigiri sushi. You have probably seen Nigiri sushi and Nori maki before. If you do not like fish and nori, you have probably eaten them.

However, many people, including the Japanese, misunderstand Nigiri sushi.

They think that Nigiri sushi is sushi with sashimi such as salmon on top of vinegared rice. Many cookbooks and other books say this as well, so it is no wonder they understand it incorrectly.

To correct here, nigiri sushi consists of prepared fillets on a bed of vinegared rice. Preparation means sprinkling salt on the seafood, soaking it in vinegar or soy sauce, boiling it, simmering it, etc. This preparation is called Edomae shigoto (Edo-style preparation) in Edomae sushi restaurants. To confirm, sashimi is unheated seafood or other ingredients cut into small pieces.

Why do they dare to prepare super-fresh seafood?

The reason is said to be that in the Edo period, there was no such thing as a refrigerator, and people had to devise ways to keep seafood from spoiling even a little.　Then it seems that it is not necessary now. However, this preparation process helps to make seafood more delicious (to give an example, inosinic acid is produced, which, combined with the glutamic acid and other substances that seafood originally contains, produces a synergistic effect of umami). This is why they still use prepared seafood today.

On the other hand, salmon nigiri sushi found overseas uses sashimi. Even in Japan, in regions where fresh seafood is available, sashimi is used. This is because the priority is not the synergy of umami, but rather the texture and security of freshness. And there is no way to know that this is clearly different from Edomae sushi (Nigiri sushi) on the main road.

If you make nigiri sushi with sashimi, you don’t have to be a sushi chef to do it. In fact, to put it bluntly, anyone can do it. There is an experience to make Nigiri sushi for tourists, but you understood that this is only to make Nigiri sushi in appearance, right? And to learn Edomae shigoto (Edo-style preparation), the sushi chefs need a long period of training.

Let’s get to the point here.

Here are 8 sushi toppings you should try in Tokyo. We divided it into 4 so that you can see the opportunity to eat.

The first is the typical sushi toppings at Edomae sushi. It is a sushi topping that can be eaten regardless of the season (of course, there is a season), but it shows the characteristics of the sushi restaurant. The boiled Kuruma ebi, with its beautiful red color, aroma of the sea, and complex umami, is a must-try. Next is not eel but Anago (Japanese conger). The soft- simmered anago instantly falls apart in your mouth, spreading the ummai of the fish, and the restaurant’s unique sauce, called Nitsume, is not to be missed.

Second, sushi toppings are only available at certain times of the year. The season is short, so even if you want to eat it, you will have to wait until the next year when the season is over. For example, don’t you think you can eat Bluefin tuna all the time? The season for fresh bluefin is from around September to early January. This is the time when all parts of the fish are at their best. Shinko, the juvenile kohada, can cost as much as $2,000 per kilogram at the beginning of the season, and sushi chefs are forced to pay a premium for this fish because sushi lovers compete to be the first to eat it. The taste is not as good as kohada, but the aroma may be a cut above.

Chum salmon is not eaten raw in Japan. This is because of problems such as anisakis. Even so, you should definitely try Keiji (young Chum salmon) nigiri, which has a completely different quality of fat. It is very rare and costs more than US$1000 per fish. Then there is Hoshigarei, the king of flounder. The moderate fat and fresh aroma will fascinate you. Next, the Red sea urchin is caught in Kyushu and other parts of Japan. Sea urchin has a rather complex flavor. However, red sea urchin has a refreshing aftertaste. It is a mysterious sushi material.

The fourth is the sushi items that you should eat without grumbling. You should be happy to eat these items in season. Ezobafununi, caught in Hokkaido during the summer, is exceptional. Many people say they can’t eat sea urchin, but if you eat this, you’ll become a sea urchin lover. And then there is Akagai (Ark shell). Many shellfish enjoy the delicate balance of sweetness and bitterness, but Ark shell is a great ingredient to enjoy the scent of the sea.

If you want to eat Hamachi or Salmon, which you often eat as Nigiri sushi, you have to go to a conveyor belt sushi restaurant. Buri, which is farmed, is called Hamachi. Salmon is also mostly farmed, with Norway and Chile being the world’s leading producers. There is no point in going all the way to Tokyo to eat them.

Finally, sushi chefs tend to avoid farmed fish. And the same goes for frozen fish. Some fish can only be used for Nigiri sushi if they are live. The chef cooks fish deliciously, but sushi chef is only trying to bring out the true flavor of the fish. In other words, there is no compromise in the selection of seafood. If the fish is too expensive, sushi chefs may not buy it. And sometimes they have to buy it even if it is too expensive. For your information.

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Revision date: August 12, 2023

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What is K value, a formula to evaluate the freshness of fish?

a photo of Fish market — A fish market is a marketplace used for marketing fish products. It can be dedicated to wholesale trade between fishermen and fish merchants, selling seafood to individual consumers, or both.

As fish and meat age, their components change, losing their deliciousness while at the same time producing dangerous components that can be harmful to the body. Freshness is determined by the amount of time that has passed since the fish was caught. By knowing the freshness, we can tell how fresh the food is, and at the same time, we can tell if it tastes good and is safe.

To swim, fish consume adenosine triphosphate (hereafter referred to as ATP) in their muscles to generate kinetic energy. While the fish is alive, ATP is resynthesized through respiration and the breakdown of glycogen in the body, even if the muscles are fatigued.

However, if they die and are no longer supplied with new ATP, the binding of actin and myosin, the proteins that make muscles stretch and contract, proceeds unilaterally. In combination with the acidification caused by the breakdown of ATP and the formation of lactic acid, the muscles remain contracted. This is the onset of rigor mortis. Finally, ATP is lost and rigor mortis is completed. If a fish dies while its body is exhausted from strenuous exercise, rigor begins earlier than normal. This means that ATP is consumed when fish resist violently to avoid being caught.

K value is a scientific and objective standard for judging the freshness of fish and other products.

To begin with, the postmortem flesh of fish is said to be alkaline. It becomes more acidic over time. In the process of this change, ATP is broken down into several acids as shown below, and the K value is a mathematical formula that captures some of these acids and calculates them.

ATP→Adenosine diphosphate（ADP）→Adenosine monophosphate（AMP）→inosinic acid（IMP）→hypoxanthine riboside（HxR）→Hypoxanthine（Hx）

The formula is as follows:

K value (%) = (HxR+Hx)/(ATP+ADP+AMP+IMP+HxR+Hx)×100

The rate of degradation varies among fish species, but the pathway to HxR is constant. Fish that die quickly after catching have more ATP, ADP, and AMP. Then, as time passes, IMP increases and finally HxR and Hx increase. These HxR and Hx present a tasteless or bitter taste, which causes a decrease in deliciousness. In other words, a high amount of HxR and Hx is evidence of reduced freshness.

In general, fish with a K value of up to 20% can be eaten raw, i.e., as sashimi. In the case of fish, the K value is about 5% immediately after ikejime. 20-40% is considered to be good freshness. Sushi toppings are around 40%, which is not low by any means, but it is at this value that the flavor of the ingredients is most likely to be extracted. In other words, it is a state of maturing and increased IMP. And if it is 40-60%, it is edible if cooked. In other words, it is better to eat simmered or grilled fish. If it is over 60%, it is in a state of decomposition. Naturally, it is not suitable for eating. It is also known that the rate of increase in K value is large for cod and red-fleshed fish, while the rate of increase in K value is small for white-fleshed fish such as red sea bream and flatfish.

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Revision date: July 25, 2023

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The rating of fish in the Edo period was totally different from that of today!

a photo of Rating — In the Edo period, people rated various things. It seems that there was such a rating chart.

Tuna, which is now a representative of high-class fish, was one of the lower ranks of Gezakana (ge means ‘cheap’, and zakana means ‘fish’) in the Edo period. According to an encyclopedia of the Edo period, “maguro is a very vulgar fish, and even common people who live in houses facing the main street would be ashamed to eat it. Maguro was so low-ranked fish that was said to be the food of poor people living in houses on back streets. However, due to the effects of global warming and overfishing, the number of fish called Gezakana has been decreasing. Therefore, meat is definitely cheaper than fish in supermarkets.

Next, please take a look at the ratings of fish in the Edo period as listed in Chiba University‘s study of classical cuisine.

The following fish are listed as Jyozakana (Top-grade fish)

Tai、Ankou、Amadai、Sayori、Shirauo、Suzuki、Sawara、Ishigarei、Ayu、Tara、Akagai、Kaki、Karei、Kisu、Kurumaebi

The following fish are listed as Chuzakana (Middle Fish)

Tako、Kochi、Hirame、Aji、Ara、Ika、Katsuo、Houbuo、Ishimochi、Ungai、Ainame、Asari、Hamaguri、Bora

The following fish are listed as Gezakana (Lower fish)

Buri、Kurodai、Saba、Iwashi、Fugu、Kohada、Mutsu、Okoze、Shimaaji、Maguro、Nishin、Same

Again, maguro is classified as Gezakana, along with today’s high-end fish such as Kurodai and Fugu, and it seems that most Jyozakana are white fish, and the oily fish, so much appreciated today, was not favored by the people of Edo. In addition, maguro was also called shibi (pronounced “shi,” which is a reference to death), and some believe that it was not popular because it was associated with death.

When large schools of maguro appeared in the seas around Edo (Tokyo) between 1340 and 1844 and were caught in large numbers, they were sold for free because they were not popular.

As a side note, a sushi restaurant made a fortune by purchasing maguro red meat at a low price, marinating it in soy sauce, and selling. This was the beginning of what is now called Zuke.

n this way, red meat was still sometimes preferred, but Toro, which tends to spoil easily, was not looked upon and was often thrown away. Even if it was eaten, it was only in Negima nabe (hot pot) and was rarely eaten raw.

It was not only in the Edo period that toro was not favored.

It was not until the development of refrigeration and freezing technology in the 1945s that otoro and chutoro became as much appreciated as they are today. It is only recently that Otoro and Chutoro have become the kings of fish. Fish grading, in fact, has a great deal to do with safety. Saba, which suddenly loses its freshness, and Iwashi, which is tender and easily loses its freshness, are both Gezakana. In other words, fish that lose their freshness easily were likely to be classified as gezakana.

Another reason was the taste of the Edo people, who preferred light fish such as Amadai, Sayori, and Suzuki to oily fish such as Saba and Buri. It is understandable that Maguro Toro, which is both fatty and perishable, is frowned upon.

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Revision date: July 24, 2023

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Here’s a Michelin sushi restaurant where photography is not allowed!

a photo of Kuromutsu nigiri sushi — Kuromutsu were disturbers a long time ago when we were fishing Splendid alfonsino (Kinmedai). And they were not really liked by Edo people who don’t really like oily taste.

In this age of social networking, there is a certain discomfort in not being able to take pictures of your food. But sushi restaurants don’t want people to write bad things about them, and most of all, other customers may feel uncomfortable about the sound of the shutter. Especially for regular customers, this behavior is not funny. On the other hand, it is human nature to want to show off on social media or record your visit to a restaurant where reservations are hard to come by. It is the policy of the restaurant, so if you cannot follow it, just don’t go there.

Therefore, we investigated Michelin sushi restaurants where photography is not allowed.

Of the 30 sushi restaurants that received stars in the Michelin Guide Tokyo 2023, the following five are among those where photography is prohibited. Of these, Sawada in Ginza is the only one that has not been photographed, probably because it has been prohibited ever since it moved from Nakano to Ginza. The other four have been banned at one point or another. This means that at the remaining 25 establishments, Oyakata (Sushi master) is still allowed to take pictures, albeit reluctantly. However, the sound of the shutter is not very pleasant, so care must be taken when taking pictures.

Sushi Yoshitake

Sawada

Sushi Kanesaka

Takagaki-no-sushi

Sushi kuwano

Next up is a sushi restaurant previously awarded a star in the Schlumberger Guide Tokyo where photography is not allowed. Sushi Arai will open a new restaurant on the second floor of the same building in spring 2021, in addition to its previous location on the basement floor. Photography is not permitted at the new restaurant. Sukiyabashi Jiro will be replaced by the eldest son, and in my opinion, it will become OK (it is still NG). The reason is that the customers will be replaced by new ones.

Sukiyabashi jiro

Sushi Arai

In summary, if the restaurant offers the Omakase course, which is strongly recommended, we would like to be allowed to take pictures. The reason is that we are eating at the convenience of the restaurant, so “we are cooperating, right? Let me at least take a picture”. As one example, Sushi Saito, which has been awarded three Michelin stars for 10 consecutive years, has a section that considers photography as part of its service. On the other hand, if you eat at Okonomi, the sushi chef and the restaurant are both forced to work hard, and you are told to “Eat quickly” before taking any pictures. For your information.

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Revision date: July 22, 2023

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What are Komono-ya and Oomono-ya?

a photo of seafood wholesalers in Tsukiji — As of April 2020, the Toyosu market will have 481 seafood wholesalers.

As of April 2020, the Toyosu market will have 481 seafood wholesalers, a decrease of 55 from two years ago, when the old Tsukiji market was still in operation. More specifically, it is down about 30% from 664 in 2014. As of June 2021, the demand for seafood from restaurants and other businesses has decreased significantly due to the new coronavirus, and the business conditions are worrisome. In case you are wondering, there were about 1,600 middle wholesalers in the Tsukiji market at its peak.

Nevertheless, the reason there are so many of them and they are all doing business in their own way is because they are all specialty stores. There are many types of seafood, such as tuna, fresh fish, shrimp, shellfish, and dried fish, which require specialization. Recently, seafood wholesalers have begun to offer other specialties in order to expand the scale of their business. In the old days, however, there were “Akamono-ya” (aka means “red” and mono means “fish”) that dealt only with tai, “Jomonoshi” (jo means “good quality”) for ryotei, “Kajiki-ya” for Kajiki (Marlin), and so on, all of which were divided into many different categories. Incidentally, “ya” is added after a product to indicate the store or occupation that handles that product.

“Komono-ya” refers to restaurants that specialize in sushi items and tempura ingredients. Sushi items are often small, such as Kohada, Kisu, Anago, Akagai, and Tako. That is why it is called Komono-ya. If there are small items, there are also big ones. Oomono-ya (Oo means Big) deals in tunas. Tuna is a big fish, and Oomono-ya is the name of the seafood wholesalers because they deal in tunas. There are about 200 tuna wholesalers in Toyosu, but only a few wholesalers sell only fresh bluefin tuna caught in the waters around Japan throughout the year. Fujita-suisan (藤田水産), which deals with Sukiyabashi Jiro, Hicho (樋長), which deals with Nishiazabu-Taku, Yamayuki (やま幸), which deals with Harutake, and Ishiji (石司), which deals with Takaichi-no-sushi are the most famous. Almost all Michelin and Gault & Millau-rated sushi restaurants purchase their raw tuna from these four wholesalers.

In summary, these words should be understood only by those who are related to the Toyosu market, and there is no need for pretentious names. In fact, these words are very clear.

Related contents:
Toyosu market Information

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Revision date: July 21, 2023

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What are Fish paste products?

Essentially, no fish cannot be processed into fish paste products using current food processing technology. However, it is important to have a stable supply of high-catch fish species, which are inexpensive, and whose meat is suitable for fish paste products. High-catch species such as sardine and Alaska pollack are the main raw material for mass-produced fish paste products. However, many of the fish paste products that are considered local specialties in Japan are originally produced using locally caught fish. Among fish paste products, fish species other than the most prolific are used when the flavor of the product varies depending on the fish used.

Now that you understand more, let’s continue with the explanation using Kamaboko (蒲鉾), the most widely used fish paste product, as an example. The preferred fish to be used as the raw materials for Kamaboko have strong Ashi, good Suwari and doesn’t Modori easily.

Ashi refers to the moderate resilience that Kamaboko has, with a crisp and crunchy texture, proving that it is a good product. In other words, strong Ashi means that the fish has adequate firmness. Types of fish with strong Ashi include Flyingfish, Japanese aulopus, Brushtooth lizardfish, Bartail flathead, Red seabream, Golden threadfin-bream, Silver croaker, Honnibe croaker, Grub fish, Spiny goby, Indo-Pacific blue marlin, Globefish and others. Generally, Shiromi fish are considered to be strong and Akami fish are considered to be weak, while freshwater fish and shrimp are considered to be weak for the most part.

Suwari refers to the ease of surimi hardening and depends not only on the difference in type of fish, but differences also occur due to temperature and pH of the surimi, freshness of the raw fish material and how the fish was killed. In other words, poor Suwari means that the fish doesn’t firm up easily. Fish well-known for having good Suwari start with Indo-Pacific blue marlin and also include Honnibe croaker, Flying fish, Brushtooth lizardfish, Grub fish, Red seabream, etc. Fish known to have poor Suwari included crucian carp, bonito monkfish, sardines, etc. Generally, fish that live in coldwater regions have better Suwari while fish that live in warm waters and freshwater fish have poor Suwari.

Modori or Hi-modori refers to the phenomenon of weakened elasticity when fish that were hardened through the Suwari process has been further heated. Modori depends on the type, freshness and season the raw material fish was caught. Fish that don’t succumb to Modori easily include Grub fish, Needlefish, Indo-Pacific blue marlin, Starspotted smooth-hound, Flathead gray mullet, Horse mackerel, etc. Fish known to succumb to Modori easily include sardine, leatherjacket, Honnibe croaker, Chub mackerel, Crucian carps, Japanese Spanish mackerel, etc. Surimi color is reflected in the finished product, so Shiromi fish with a white finish is generally preferred over Akami fish, which results in a darker finish. However, it is possible to create a white finish, even using Akami fish, with some extra work.

Because the unique flavor of the raw fish is lost during the Surimi production process, it is common to season the fish afterward, but some specialty products are produced in such a way that the flavor of the raw fish is not lost.

Until World War II, the production of fish paste products was not organized for mass production, and many factories had only a few craftsmen at most. Only locally caught fish were used as ingredients. Since there were no refrigeration facilities, the factories had to be closed during the summer months, when it was difficult to maintain quality.

After the war, when the bottom trawling fishery in the East China Sea started, raw fish such as Silver croaker, Yellow croaker, Large yellow croaker, Eellowback sea-bream, Nemipteridae, and Largehead hairtail came to be supplied cheaply and stably. Advances in cold storage technology and distribution networks have also made it possible to mechanize the production process and mass produce products.

As a result, the production of fish paste products continued to increase in both quality and quantity, and the demand could no longer be met by inshore raw fish alone. At this time, frozen surimi from Alaska pollack appeared on the market.

Frozen surimi is a raw material made by adding sugars such as sucrose and sorbitol, which prevent protein denaturation, and polyphosphate to surimi and then freezing and storing it. The basic technology for frozen surimi was developed at the Hokkaido Fisheries Experiment Station in 1960.

Frozen surimi can be classified into three categories: unsalted surimi, which has little protein denaturation during freezing; salted surimi, which can be commercialized with high ash content; and ground surimi, which is processed at a factory from raw fish.

The quality standards for the commercialized surimi are set by the National Frozen Fish Meat Association, and there are several grades of surimi in the Alaska pollack. Most of the frozen surimi produced are made from Alaska pollack, but due to a decrease in Alaska pollack production, Red seabream and Nemipteridae caught off the coast of Hong Kong have also been used as surimi raw materials.

Types of Fish paste products

Chikuwa

Chikuwa is Surimi wrapped around a bamboo stick and heated. The baked chikuwa is called yaki-chikuwa, and the steamed chikuwa is called shiro-tikuwa. Toyohashi-Chikuwa from Toyohashi City, Aichi Prefecture, is especially famous. It is characterized by the fact that both ends are white and only the middle area is browned.

Date-maki

Date-maki is made by adding eggs and sugar to Surimi, rubbing to a foamy consistency, and then baking. Good quality is considered to be made with sharks as the raw material fish. Date-maki is known throughout Japan as a New Year’s product.

Yaki-kamaboko

Among the many types of kamaboko, yaki-kamaboko is the most common type of kamaboko in Japan. Historically, this method is the oldest.

Yaki-ita in the Kansai region is made from Daggertooth pike conger, Synodontidae, and Sciaenidae. In order to preserve the flavor of the ingredients, the process of soaking in water is shortened, and the surimi is steamed and hardened once before the surface is seared and browned.

Hanpen

Hanpen is made by adding yams to Surimi, making it foamy, and steaming it. It is characterized by the lack of ashi and a fluffy marshmallow-like texture. It is a fish paste product unique to the Kanto region, and the best fish paste products are those that use sharks as ingredients. It is one of the oldest fish paste products.

Kanikama

Kanikama is a fish paste product that has the texture, shape, color, and flavor of crab, just like crab meat. The raw material is not crab but fish surimi. The main ingredient is Alaska pollack, a white fish that has no peculiarities or odor. Other surimi such as golden threadfin-bream and largscaled saury are also used.

Mushi-kamaboko

Mushi-kamaboko was already being produced around the end of the Edo period. It is most commonly found in the Kanto area, with Odawara-kamaboko in Odawara City, Kanagawa Prefecture, being the most famous.

Odawara-kamaboko is mainly made from Sciaenidae and soaked in mineral-rich groundwater to produce a white, ashi-rich product. Odawara-kamaboko is also characterized by the abundance of Itatsuki-kamaboko.

Naruto-maki

Naruto-maki is made by coating the inside of white surimi with red-colored surimi, rolling it up in a bamboo screen, and steaming it. It is called this because the spiral pattern on the cross section is associated with the whirlpools of Naruto. It is used as a garnish for noodles and chirashi-sushi.

Sasa-kamaboko

Sasa-kamaboko is a type of yaki-kamabo. Sasa-kamaboko from Sendai City, Miyagi Prefecture, uses a mixture of Bastard halibut, Broadbanded thornyhead, and Nemipteridae as ingredients, shaped into a leaf shape, and grilled over charcoal.

Satsumaage

Satsumaage is a generic name for deep-fried surimi. The best products are made from Sciaenidae and Synodontidae. Some products from Kagoshima and Okinawa are made with brown sugar, which gives them a very sweet taste.

Hamo-ita

Hamo-ita is made from only daggertooth pike conger, steamed once, and then carefully baked. It is a specialty of Osaka.

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Revision date: June 29, 2023

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What is John dory (Matoudai) sushi?

a photo of John dory (Matoudai) — John Dory (Matoudai) is benthopelagic coastal fish, found on the coasts of New Zealand, Australia, the coasts of Japan, and on the coasts of Europe.

What is John dory (Matoudai)?

John dory (Matoudai) is distributed south of Honshu, in the East China Sea, Indian Ocean, western Pacific, and western Atlantic. It is found in sandy mud at depths of about 100 m, either alone or in small groups. The body is oval, with a marked lateral flattening. It has a large blackish-brown circular crest with a white border in the center of its body. John dory is called “Saint Peter‘s fish” in Western countries and seems to be revered by Catholics. Its scientific name is Zeus faber Linnaeus,1758.

What does John dory (Matoudai) sushi taste like?

The flesh of John dory (Matoudai) is light and mild, but lacking in flavor, so it is eaten with a variety of flavors. It is very tasty as a poire or meuniere, as it goes well with butter. In France, it is very popular as a standard meuniere along with sole.

It is characterized by its strong umami taste, and its liver is known to be very tasty. Sashimi is served with liver soy sauce, and Nigiri may be served with Kobujime.

Since its season is from fall to winter, it covers the same period as filefish. In Tokyo, there is also farmed filefish, and the sushi chef will use the filefish that is distributed in a considerable amount. Sushi restaurants that deal directly with fishing ports on the Sea of Japan side seem to get it by chance, but you almost never see it at sushi restaurants in Tokyo.

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Revision date: June 15, 2023

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What is Largescale blackfish (Mejina) sushi?

a photo of Largescale blackfish (Mejina) — Largescale blackfish (Mejina) lives in rocks close to the shore and look for seaweed to eat. It creates an unique, delicious flavor come with a strong sea smell and it taste out a little bit firm with slightly sweet.

What is Largescale blackfish (Mejina)?

Largescale blackfish (Mejina) is distributed throughout Japan south of southern Hokkaido, Taiwan, and the East China Sea. Its bodies are oval and flattened, and its body color is blackish purple. It is diurnal and forms schools, moving to deeper waters offshore as it grows.

It can grow up to 60 cm in length, but most of those on the market are about 40 cm in length. In summer, it feeds on animal food such as small shrimps, and in winter, it prefers vegetable food such as seaweed and nori, which means that the season is winter, as the fish’s smell of the sea disappears and it becomes fatty during the winter.

The name of this species in the Kansai region is “Gure,” and it is a popular rock-fishing target. Its scientific name is Girella punctata Gray, 1835.

What does Largescale blackfish (Mejina) sushi taste like?

a photo of Mejina nigiri sushi — Largescale blackfish (Mejina) is mildly oily and a delicious white meat fish. There is a layer of umami under the skin so we’d advise to serve seared or yubiki with the skin-on.

Largescale blackfish (Mejina) looks like red seabream (Tai), but are related to Japanese sea bass (Suzuki). The Kuromejina (Girella leonina (Richardson,1846)) and Okinamejina (Girella mezina Jordan & Starks, 1907) are members of the Mejina family, but the Mejina has the best taste.

It can be served as sashimi, grilled, simmered, or even cooked in a pot. It is relatively easy to cook because it is well suited to cooking methods that use oil. If the gall bladder is accidentally broken, a strong odor can be passed around in the air, which can make it smell even worse. Therefore, it is important to avoid damaging the internal organs when cooking it.

It is inexpensive, but because it is not caught in large numbers, it is not always available at sushi restaurants. Its flesh is a beautiful pale pink color, which is hard to imagine from the black body surface.

In winter, it has a stronger taste than red seabream, with the fat coming in closer to the mouth and a stronger umami. In the summer, it can have a slightly peculiar aroma, so it is best to yubiki (parboil) or broil the fish before serving it as nigiri sushi.

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Revision date: June 12, 2023

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What is Slender sprat (Kibinago) sushi?

a photo of Slender sprat (Kibinago) — The slender sprat is valued as food in Japan, where it is known as kibinago. These can be eaten raw, as sashimi, or cooked, as whitebait.

What is Slender sprat (Kibinago)?

Slender sprat (Kibinago) is distributed south of central Honshu, the Indian Ocean, and the western Pacific Ocean. They are found in large schools on the surface from the coast facing the open sea to offshore. Its body length is 8~10 cm. It has an elongated body shape like Japanese anchovy at first glance, and is yellowish-white overall, with a bluish back and one bright silvery-white longitudinal stripe on the body. The season is summer. In the Satsuma region of Kyushu, it is highly prized as a local dish, and sashimi, arranged in the shape of chrysanthemum flowers, is famous. In Kagoshima, it is often served with vinegared miso. The scientific name is Spratelloides gracilis (Temminck & Schlegel, 1846).

What does Slender sprat (Kibinago) sushi taste like?

a photo of Kibinago nigiri sushi — Several fillets of kibinago are placed on top of the shari, and a shiso leaf is placed between the shari and the fish. A dab of grated ginger and some nikiri shoyu is then applied.

Slender sprat (Kibinago) cannot adapt to environmental changes. They need clean underwater to survive. Even in well-equipped aquariums, there are no examples of successful long-term breeding. In addition, their freshness deteriorates very quickly after death, so in the past, only people at fishing ports were able to eat them as sashimi.

When made into nigiri sushi, the fish is eaten with several pieces of hand-opened neta (topping). It is rich in flavor and uses scallions and ginger as condiments. This nigiri sushi should be paired with Satsuma shochu, a local specialty.

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Revision date: June 8, 2023

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What is Sailfin poacher (Hakkaku) sushi?

a photo of Sailfin poacher (Tokubire) — The appearance of Sailfin poacher (Tokubire)

What is Sailfin poacher (Hakkaku)?

Sailfin poacher (Hakkaku) is distributed north of Toyama Prefecture on the Sea of Japan side, north of Miyagi Prefecture on the Pacific side, east coast of the Korean Peninsula, and Peter the Great Gulf. It inhabits shallow muddy areas at depths of about 150 meters. Body color is light blackish brown, and length reaches 40 cm.

The head is triangular in shape, and the body surface is angular, covered with spiny bony plates, and nearly octagonal in cross-section. It has a beard like a catfish. The male’s fins are exceptionally large, hence the name Tokubire (Toku means special and bire means fin), while sushi chefs call it Hakkaku (Hakkaku means octagonal) because of the shape of its cross-section. The season is around from December to February. The scientific name is Podothecus sachi (Jordan & Snyder, 1901).

What does Sailfin poacher (Hakkaku) sushi taste like?

a photo of Sailfin poacher (Tokubire) sushi — Sailfin poacher (Hakkaku) is a chewy white fish with the perfect amount of sweet fat and rich flavor.

Sailfin poacher (Hakkaku) is not well-known south of the Tohoku region, but it is popular as sushi material at sushi restaurants in Hokkaido. Contrary to its appearance, it is a fatty white fish with a crunchy texture and a rich flavor and sweetness of fat that spreads in the mouth. Usually the white meat is clear, but its flesh is murky white due to the presence of lots of fat. Also, males are larger and have more fat.

However, because of this shape, the yield rate is quite low. Because there are so few of them in Hokkaido, even many Hokkaido residents know of them but have never eaten them, so they are almost never available at sushi restaurants in Tokyo.

You can find Hakkaku at Izakaya because it can be prepared any way you like: “salt-grilled,” “dried overnight,” or “deep-fried.”

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Revision date: June 7, 2023

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What is Black scraper (Umazurahagi) sushi?

a photo of Black scraper Umazurahagi) — Black scraper is a filefish with high market value but the standing stock has been decreased in the past years due to the overexploiting and environmental fluctuations.

What is Black scraper (Umazurahagi)?

Black scraper (Umazurahagi) is distributed in the Sea of Japan from Hokkaido to Kyushu, the Pacific Ocean, the Yellow Sea, and the East China Sea from the Korean Peninsula to the coast of China. It is a familiar fish caught throughout Japan. Umazurahagi are called nagahagi (naga means long) because they are longer than Filefish (Kawahagi).

They are abundant at depths of around 10m, slightly offshore from Filefish. When young, around 10 cm in length, they migrate in schools, but as adults, they are often found alone. Adults gather in coastal areas to spawn from around May to July and dive to deeper water around November.

They are omnivores, feeding on benthic organisms such as seaweeds, crustaceans, polychaetes, and even jellyfish. Its scientific name is Thamnaconus modestus (Gunther,1877).

What does Black scraper (Umazurahagi) sushi taste like?

a photo of Umazurahagi nigiri sushi — Black scraper (Umazurahagi)’s white flesh has an elegant sweetness and a crunchy, pufferfish-like texture.

Black scraper (Umazurahagi) has a blurry appearance and does not look tasty, but once peeled, it reveals a clear white flesh similar to that of pufferfish.

The price of Umazurahagi is completely different between those caught in large quantities by bottom trawling fishing and those caught by pole and line fishing. Therefore, Ikejime or live fish are used for sushi toppings.

The liver, with its rich flavor, can be raw or seared and used in nigiri sushi to make an exceptional dish. Although it is looked down upon compared to Filefish and pufferfish, it is relatively affordable and highly regarded as a topping, and is not a substitute for Filefish at all.

However, the quantity of fish received at the Toyosu market and other markets is not stable. From that point of view, few restaurants offer nigiri sushi.

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Revision date: June 6, 2023

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What is Japanese scaled sardine (Mamakari) sushi?

a photo of Japanese scaled sardine (Sappa) — Sappa (Japanese scaled sardine) and kohada (Gizzard shad) are similar, but the dorsal fins of the sappa are not thread-like and there is no black dotted line on the body side.

What is Japanese scaled sardine (Mamakari)?

Japanese scaled sardine (Mamakari) is distributed south of Hokkaido, the Yellow Sea, and Taiwan. It inhabits shallow sandy muddy areas near the mouths of estuaries in inner bays. Its standard Japanese name is Sappa, and its length reaches 15 cm. Juvenile fish can be caught in large numbers in small fixed nets, but It has little market value and are treated as small fish.

The morphology and ecology of this species are similar to that of the Gizzard shad (Konoshiro) throughout the egg, juvenile, and young stages, but the adult fish clearly differ in body color and dorsal fin shape. In Japanese scaled sardine, the blue on the dorsal side and the white on the ventral side are clearly separated and vivid. Its scientific name is Sardinella zunasi (Bleeker, 1854).

What does Japanese scaled sardine (Mamakari) sushi taste like?

a photo of Mamakari nigiri sushi — Mamakari nigiri sushi is an indispensable dish for festivals and family celebrations, and is a representative dish of the special days in Okayama.

In Okayama, Japanese scaled sardine, a close relative of gizzard shad, is called Mamakari and is highly prized. It is in season from fall to winter and is the finest Mamakari with fine texture and fat.

Fresh Mamakari nigiri sushi, lightly vinegared, has a unique Okayama flavor that is different from that of Gizzard shad (Kohada). One thing to note is that, as with other herring species, there are many small bones, so it is easier to eat them if they are pickled in vinegar. It can be said that it is a dish that refreshes the palate and whets the appetite.

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Revision date: June 5, 2023

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What is Marbled rockfish (Kasago) sushi?

a photo of Marbled rockfish (Kasago) — Small marbled rockfish (Kasago) are best deep-fried or simmered, while good-sized ones are also tasty as sashimi.

What is Marbled rockfish (Kasago)?

Marbled rockfish (Kasago) can be found anywhere along the coast from southern Hokkaido to the East China Sea. It lives in the shadows of reefs and blocks from the coast to depths of about 60m to 200m. A voracious carnivorous fish, it preys on crustaceans such as small shrimps, polychaetes such as ragworm, and small fish such as gobies.

Body color varies from dark brown, reddish, to blackish, and there is a great deal of variation depending on the environment in which they live. Those that inhabit deeper water are said to be redder, while those that inhabit shallower water are said to be darker. Another characteristic of this species is the irregular white patches on its back side.

Along with Mebaru and Ainame, it is a representative of rockfish (It is a fish that does not migrate far and has a small habitat). It is about 30 cm long. Its scientific name is Sebastiscus marmoratus (Cuvier, 1829).

Some species of marbled rockfish have poison lines on their pectoral fins and dorsal fins, so care should be taken when cooking them. Also, since they have many spines all over their body, when grabbing a live fish, put your thumb in their mouth and grasp their lower jaw.

It is generally considered a winter fish, but the season is spring. It is most fatty from January to April, and the black ones that inhabit the seashore are said to be tastier than the reddish marbled rockfish that inhabit offshore waters. It can be caught in all regions of the Japanese archipelago, which stretches from north to south, a light white fish that is easy to remove from the bone, so it is delicious regardless of the season. The larger ones are often made into sashimi or sushi, while the smaller ones are often eaten as boiled fish.

What is Marbled rockfish (Kasago) sushi taste like?

Marbled rockfish (Kasago) is treated as a high-end fish in the Toyosu market, but the supply is not consistent. In addition, its large head and low yield make it rare for restaurants to serve nigiri sushi and sashimi.

The elegant flavor of nigiri sushi and sashimi is, to put it mildly, unsatisfying. The best way to eat nigiri is to broil the skin and let the aroma come out. This will dissolve the gelatinous material under the skin, and the sweetness and umami of the fat can be felt gradually. It is also good to eat it with citrus fruits such as sudachi and salt.

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Revision date: May 27, 2023

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