What is Flying fish (Tobiuo) sushi?

a photo of Flying fish (Tobiuo)
Flying fish (Tobiuo) can be seen jumping out of warm ocean waters worldwide. It is thought to have evolved this remarkable gliding ability to escape predators, of which they have many. Their pursuers include mackerel, tuna, swordfish, marlin, and other larger fish.

What is Flying fish (Tobiuo)?

Flying fish (Tobiuo) is distributed in warm seas south of central Honshu and around Taiwan, living in the surface layer from the coast to offshore. Its body length is about 30 cm. Its body is long and slender, and its pectoral fins are large and wing-like, used for flying above the sea surface.

It migrates northward from southern Japan in the spring with rising water temperatures and southward in the autumn with falling water temperatures. Flying fish usually migrate near the surface of the ocean in schools, reaching speeds of 35 km/h on the surface and 55 km/h in the air, depending on the species and size of the flying fish. They also glide like gliders at a height of 4 to 5 meters and a distance of 100 to 500 meters in a single flight.

The name Tobiuo (Flying fish) is used as a generic name for the Exocoetidae, but the Narrowtongue flyingfish, which is typical of the waters around Japan, is distinguished by the name Hon-tobi. It is 30 to 35 cm in length and migrate northward in schools on the Kuroshio Current, approaching the coast from April to July to spawn. Another representative Tobiuo is the slightly smaller Dark-edged-winged flyingfish (Hoso-tobi), also known as Maru-tobi or Nyubai-tobi. The scientific name is Cypselurus agoo (Temminck and Schlegel, 1846).

What does Flying fish (Tobiuo) sushi taste like?

Flying fish (Tobiuo) is fresh if it has a shiny surface and shiny blue-black back, and if its eyes are clear. The freshness of the flying fish is also assured by the fact that its digestive tract is small and the food it eats is immediately expelled from the digestive tract. Fresh fish is the best choice for sashimi. The flesh is slightly soft, not too watery, light, and has no peculiar taste. However, sushi topping is not generally used for Edomae sushi.

a photo of Ago dashi
Ago-dashi has a refined taste and flavor. It is used in various dishes ranging from miso soup to simmered dishes. Especially it goes well with Ramen (noodles).

Flying fish is also called “Ago” in Japanese. “Ago” is the dialect around Nagasaki. Flying fish, which contains less fat than other fish, is dried and used as dashi (fish stock). Dashi of dried flying fish is called “Ago-dashi”. This is one of the highest-quality dashi.

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Revision date: April 28, 2023


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What is Whitebait (Shirasu) sushi?

a photo of Whitebait (Shirasu)
Whitebait (Shirasu) is a generic term used worldwide to describe small fish, often juveniles, which are collected in quantity and eaten whole.

What is Whitebait (Shirasu)?

Whitebait (Shirasu) is a generic name for juvenile fish without pigmentation, such as Pacific sand lance, Japanese eel, Japanese anchovy, Japanese sardine, round herring, Ayu, and Pacific herring. The most commonly seen Whitebait (Shirasu) in the market is the Japanese anchovy.

Japanese sardine spawns from winter to spring, round herring from April to June, and Japanese anchovy spawns all year round, but spawning peaks especially in spring and fall. Shirasu in spring are small but plump, and shirasu in fall are fatty, but each has its own unique flavor.

What does Whitebait (Shirasu) sushi taste like?

a photo of shirasu gunkan maki
Conveyor belt sushi restaurants made Whitebait (Shirasu) available for sushi.

Only raw Shirasu can usually be eaten only on the same day it is caught. Because of the rapid loss of freshness, it is not always possible to eat it even if you go to the area when the weather is slow or the catch is poor. Generally, this food has been preserved by boiling (釜揚げ) or sun-drying (天日干し).

Whitebait has a high water content, so it is good manners to eat it quickly once it is made into a Gunkan maki. Its rich flavor and bitterness go well with the refreshing vinegared rice, and the condiments used are green onions and ginger. It was a local sushi restaurant that popularized raw shirasu sushi, which is eaten when it is in season. These days, it is also available at conveyor-belt sushi restaurants, but this one is quick-frozen.

a photo of Shirasu sashimi
You can fully enjoy the elegant sweetness and sticky texture of fresh Shirasu.

On the other hand, Edomae sushi restaurants do not offer nigiri sushi, only serving it as Tsumami.

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Revision date: April 21, 2023


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What is Blue mackerel (Gomasaba) sushi?

a photo of Blue mackerel (Gomasaba)
The blue mackerel is native to the tropical and subtropical waters of the Pacific Ocean. Its range extends from Japan to New Zealand, in smaller quantities it can also be found off the coasts of the eastern Pacific and in the Indo-Pacific.

What is Blue mackerel (Gomasaba)?

Blue mackerel (Gomasaba) is distributed south of Wakasa Bay on the Sea of Japan side and south of the Boso Peninsula to the East China Sea on the Pacific side and in the northeast Pacific off Australia, New Zealand, Hawaii, and Mexico. And recently, they have been appearing in southern Hokkaido due to rising sea temperatures near Japan. They migrate northward along the coast of Japan in summer in pursuit of prey, and after spawning, migrate southward in autumn. The season is summer.

Compared to Chub mackerel (also called Pacific mackerel), the Blue mackerel has a fuzzy, irregular pattern on its back and scattered black-gray spots on its belly. These spots are goma (sesame seed)-like, hence the name Goma (Sesame) mackerel. Chub mackerel, which are tall and flat, are called Hira (Hira means flat)-saba, whereas Blue mackerel is called Maru (Maru means round)-saba because of their round body. The length of the fish is about 40 cm. Its scientific name is Scomber australasicus Cuvier, 1832.

What does Blue mackerel (Gomasaba) sushi taste like?

a photo of Gomasaba nigiri sushi
There are different ways of preparing saba sushi. The most common variant today is marinated mackerel (shime saba) as nigiri sushi.

In Japan, most mackerel used for nigiri sushi is chub mackerel, and blue mackerel is rare. This is because Chub mackerel contains 16.8g of fat per 100g of edible part, while Blue mackerel contains only 5.1g of fat, so it is generally said to be inferior to Chub mackerel. On the other hand, Chub mackerel loses its flavor in summer, while Blue mackerel remains the same all year round.

But with the recent increase in catches, the reputation of Blue mackerel is changing. This is spurred by the appearance of blue mackerel that can be eaten raw. These include “Shimizu-saba (清水サバ)” from Kochi and “Kubiore-saba (首折れサバ)” from Kagoshima. Kubiore means “broken neck” and refers to a processing step after catching.

Mackerel is now also commonly served raw, but traditionally it is made with Sujime. The Sujime method, a preparation involving salt and vinegar, is used to preserve freshness, suppress odors and reduce the dominant inherent flavor of mackerel. The meat treated in this way is called Shime saba.

Some chefs sear the Sujime blue mackerel on straw to give it a savory aroma and soften the skin. Some chefs place Shiraita Kombu (a translucent thin slice of Kombu) on top of the topping to soften the acidity of the Sujime. We have a feeling that blue mackerel will be used in nigiri sushi from now on.

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Revision date: April 17, 2023


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What is Sweetfish (Ayu) sushi?

a photo of Ayu (Sweetfish)
A small sweetfish is used for nigiri sushi.

What is Sweetfish (Ayu)?

Sweetfish (Ayu) is distributed throughout East Asia from southern Hokkaido to Kyushu, the Korean Peninsula, and northern Vietnam. The species found on Amami-Oshima Island and Okinawa Island is called Ryukyu-ayu and is a differentiated subspecies. Ayu is characterized by the oval yellow spots on the upper pectoral fins and a dozen rows of comb-like teeth aligned on the lip.

It is born near the estuary in the fall, goes down to the sea to overwinter, returns upstream the following spring to become an adult, and then migrates back downstream to spawn and live out their lives. In some lakes, such as Lake Biwa, a land-locked type is found that completes its life in the lake instead of the ocean. These groups are called Ko-ayu. Aquaculture is also popular, with Gifu, Hiroshima, Kochi, and Kyushu being well-known production areas. The scientific name is Plecoglossus altivelis altivelis (Temminck and Schlegel, 1846).

The traditional names used to describe the fish are “Kou-gyo (fragrant fish)“ (because of its unique scent), “Nen-gyo (annual fish)“ (because it usually lives only one year), “Ginko-gyo (silver-lipped fish)“ (because its mouth glows silver when it swims), Keiun (means sardine in a mountain stream) and “Sairin-gyo (scaled fish)“ (because of its small scales).

What does Sweetfish (Ayu) sushi taste like?

a photo of Ayu sushi
When making nigiri sushi, the head of the ayu fish is sometimes left on or the skin is removed.

Adult ayu feeds on algae on the surface of stones in the river, giving them a distinctive aroma like that of watermelon or cucumber, which can already be smelled even by young fish in the upstream season. The season is from July to August when ayu put on fat, but the aroma is stronger when young ayu are caught a little earlier.

When preparing nigiri sushi, small wild ayu is used, the head and entrails are removed, and the belly is cut open and the inside bone is removed. In traditional Ayu sugata sushi (whole fish sushi), the fish is thoroughly salted to drain off the water and make it strong sujime. Then let it rest in the refrigerator for half a day. If the fish is small ayu, the skin can be left on, but if the size is large or the sushi is to be made immediately after soaking in vinegar, the skin is often felt hard, so it is removed. Ayu belongs to Hikaramono in the sushi category, perhaps because of its shiny appearance. There are very few sushi chefs who make Ayu’s nigiri sushi, so Sushi Sanshi (鮨三心), Sushi Ikko (鮨一幸), Kanda Sasazushi (神田笹鮨), etc. have it on their signature menu. It was the most popular autumnal sushi item during the Edo period.

a photo of Ayu shioyaki
When eating salt-grilled ayu fish, it is good manners to taste the whole fish, but the head and tail can be left behind.

To enjoy the elegant appearance and aroma of ayu, grilled with salt is the best way to go. The fish is put on a skewer in such a way that their body forms a wave, making them look as if they are swimming (it is called uneri gushi). It is traditionally eaten with water pepper vinegar, which goes well with it.

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Revision date: July 4, 2023


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What is Aka-nishi-gai (Ko-naganishi) sushi?

a photo of Top shell (Aka-nishi)
This is Aka-nishi (Top shell) nigiri.

What is Aka (aka means red)-nishi-gai (gai means shell)?

There are three typical types of shellfish called Aka-nishi-gai: Naganishi, Ko-naganishi, and Aka-nishi. Yonaki-gai (夜泣貝), enthusiastically favored in Hiroshima and Yamaguchi prefectures, is the Naganishi (Fusinus perplexus (A.Adams,1864)) caught in the Seto Inland Sea. It is no longer caught in large quantities, and Ko-naganishi (Fusinus ferrugineus Kuroda & Habe,1961) from the Sea of Japan is used as a substitute. This shellfish is a smaller version of the Naganishi, and has a unique astringent taste in its entrails.

Aka-nishi (Top shell) is a carnivorous shell commonly found in tidal flats of inner bays in Japan, and in the Kanto region, it is a natural enemy of oysters and clams rather than a target for fishing. Its flesh is softer than that of the turban shell (Sazae), and some say it is tastier. In recent years, large quantities of frozen top shell has been imported cheaply from Turkey and Bulgaria, which face the Black Sea, so when you hear “Aka-nishi-gai” at conveyor belt sushi restaurants, you are probably talking about this. Aka-nishi-gai is considered an invasive alien species in the local market.

What does Aka-nishi-gai (Ko-naganishi) sushi taste like?

a photo of Ko-naganishi (Aka-nishi gunkan)

Ko-naganishi is a member of the family Fasciolariidae that inhabits the Sea of Japan from Mutsu Bay to Kyushu, where it grows to a shell length of about 8 cm. In Ishikawa Prefecture, it is caught in Nanao Bay (七尾湾) and is often used in sushi toppings. Its season is from September to November. The color of this shellfish is bright red, which is derived from its name. The texture is chewy and the aroma of the sea fills the mouth, and at Nigiri sushi, it is served in Gunkan maki, which some tourists come for. In Nanao, Ko-naganishi is called Aka-nishi-gai (赤西貝) instead of the standard Japanese name Aka-nishi (Rapana venosa (Valenciennes,1846)), which is a little confusing at times.

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Revision date: March 20, 2023


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What is Stone flounder (Ishigarei) sushi?

a photo of Stone flounder (Ishigarei)
Sushi aficionados will appreciate it as a truly extravagant sushi nigiri.

What is Stone flounder (Ishigarei)?

Stone flounder (Ishigarei) is distributed along the coasts of Japan, the Kuril Islands, Sakhalin, the Korean Peninsula, and Taiwan. It lives in sandy mud at depths of 30 to 100 meters, and its total length reaches 50 cm. The body surface is smooth with no scales, but there are large longitudinal bony plates on the dorsal surface of the body on the eye side and other small bony plates. In Japan, depending upon the region it will be called other names, such as Ishimochi, Ishimochigarei, or Shirogarei.

It was caught in large quantities by bottom trawling fishing and was synonymous with cheap flounder. However, since the Edo period (1603-1867), it has been treated as a luxury fish in Tokyo. This is because white fish are scarce in summer, and even now, as summer approaches, the price rises along with Japanese sea bass (Suzuki) in the market. However, there was a time when it became a phantom fish that could not be caught at all due to the reclamation and development of Tokyo Bay that began after World War II.

What does Stone flounder (Ishigarei) sushi taste like?

Stone flounder is made by quickly removing the bony plates during the preparation process to avoid the characteristic muddy smell of flounder. It has clear, elegant flesh with a moderate aroma of the sea and a rich flavor with just the right amount of crunchiness. It caught in Tokyo Bay is highly prized and is served as sashimi and sushi, but it is also delicious simmered, or grilled.

As a rule, only live fish can be used for nigiri sushi. Nojime and Ikejime are also not highly valued because the umami component of flounder rapidly decreases after death. Stone flounder, which can be found in abundance in supermarkets at reasonable prices, cannot be used for nigiri sushi or sashimi. It also has a distinctive odor when it is no longer fresh, so it is best to remove it quickly and remove the skin. Skinless fillets can be enjoyed even after maturing for a while.

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Revision date: March 17, 2023


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What is Pacific barrelfish (Medai) sushi?

a photo of Medai
The words medai is written in kanji characters as 目鯛, with “me” (目) meaning “eye” and “dai” (鯛) being the term in Japanese for snappers and porgies.

What is Pacific barrelfish (Medai)?

Pacific barrelfish is distributed throughout Japan south of Hokkaido, adult fish lives near the bottom at depths of 150 to 400 meters, and its Japanese name is Medai (Me means eye). It is a large fish, reaching 90 cm in length, with large eyes, hence its Japanese name. If the body color is red, it looks somewhat like Splendid alfonsino (Kinmedai). Its scientific name is Hyperoglyphe japonica (Döderlein, 1884).

The coloration of the body surface is generally blackish when young, but as adults, the overall coloration becomes lighter, with the back turning reddish grayish brown.

It is a member of the Japanese butterfish (Ebodai) family, which is different from the red seabream (Tai), and its body surface is slimy. The season is from fall to winter when the fish is fatty. Typical production areas are Shimane, Yamaguchi, Nagasaki, Kochi, and the inner bays of Tokyo.

What does Pacific barrelfish (Medai) sushi taste like?

a photo of Medai nigiri sushi
Pacific barrelfish (Medai) is delicious even when it is konbujime (marinated in kelp), which increases its umami.

There was a time when many market participants had a negative image of Pacific barrelfish, as many of the frozen products were not as fresh as they should have been, and the taste was not good enough. Around 2022, the impression of Pacific barrelfish changed due to its good fat content and texture, and it became a popular fish purchased by famous sushi restaurants.

The local producers have begun to improve the quality of Pacific barrelfish, and Shizuoka Prefecture’s suppliers have begun to treat it with the same care as their famous Splendid alfonsino. It may become a star like Splendid alfonsino (Kinmedai) and Blackthroat seaperch (Nodoguro) in the future.

a photo of meda ifillet
It is really a beautiful fillet.

Pacific barrelfish has a beautiful reddish-red color of chiai (dark-colored flesh) on its white flesh when cut into pieces, making it a good-looking sushi fish. It has a sweet taste and is cheaper than other shiromi such as Red seabream (Tai), Bastard halibut (Hirame), and Greater amberjack (Kanpachi). When making nigiri sushi, it should be made into shiojime and refrigerated overnight to increase the umami.

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Revision date: April 4, 2023


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What is Japanese spiny lobster (Ise ebi) sushi?

a photo of Spiny lobster
Ise ebi (Spiny lobster)

What is Japanese spiny lobster (Ise ebi)?

Japanese spiny lobster is found along the Pacific coast south of Ibaraki Prefecture and is distributed as far as Taiwan. Its length reaches up to 40 cm. Its well-known production areas include Chiba, Wakayama, Shizuoka, and Mie prefectures. Its Japanese name is Ise ebi.

It is very special to the Japanese. With its stately beard, armored appearance, and bright red color when boiled, it has long been regarded as a symbol of good luck, an indispensable part of celebratory occasions. It is also a symbol of longevity.

What does Japanese spiny lobster (Ise ebi) nigiri sushi taste like?

To be honest, it seems a waste for Nigiri sushi, as it is often used in cooking due to its good appearance. However, its flesh is resilient, and in particular, it contains glutamic acid, which is an umami component, as well as glycine and arginine, which give it a sweet taste, on a level with Kuruma prawn. It can be served raw or as Yushimo-zukuri, which brings out its sweetness and is delicious as nigiri. Some sushi chefs also use Kobujime, so adjusting the moisture content is a key point in preparation.

The name “Ise ebi” comes from the Ise Peninsula, which includes the Ise region, where it is often caught. The taste of fish caught in this region is good, and Chiba Prefecture currently boasts the largest catch of Ise ebi.

However, imported products such as Australian spiny lobster (Jasus novaebolandiae Holthuis) and Rock lobster (Jasus edwardsii (Hutton,1875)) from Australia and New Zealand are much more widely distributed. Rock lobster is distributed only in the southern hemisphere and looks different from Spiny lobster. The Rock lobster is different from the Spiny lobster in appearance, and the Spiny lobster has a transmitter that produces a sound, while the Rock lobster does not.

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Revision date: March 7, 2023


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What is Geso?

Geso is not the name of a fish or shellfish.

a photo of squid

Geso refers to the 10 arms/tentacles of a squid.

The reason squid arms came to be called “Geso” is that the shoes that are removed before entering the indoors in Japan are referred to as “Gesoku”. The name comes from a time when restaurants used to hold onto their customers shoes and the cloak would tie them with a string in 10-pair units.

a photo of geso nigiri

Geso can be lightly boiled or grilled. For large squid, a butcher knife is inserted at the tip of the arm to peel off the skin membrane, and then the tips of the arms are cut off so the sizes match. When Nitsume or other sauce is applied and it is made into Nigiri, it has an excellent springy texture and scent of the sea. It is also used as Tsumami when drinking alcohol. In my personal opinion, the Geso child of Sumiika is nice and soft and worlds above any others.

a photo of gesoThis is one of the sushi terms that even most of the general public in Japan knows well.

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Revision date: January 4, 2023


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Why are the teacups at sushi restaurants so big?!

An illustration of yunomi.
The sides of the Yunomi have the names of the fish written in Chinese characters.

This practice’s origins can be found in the street stands leftover from before WWII. It was a natural remedy for the outdoor sushi vendors who set up street booths and needed a way to maintain heat in their drinks in order to make it through the cold. In addition to lack of convenient access to water, these stands were one-man operations and the time that serving tea takes away from his time making sushi were also contributing factors. In other words, the reason the teacups are large is natural wisdom of sushi shops from long ago.

Also, hot tea has the effect of dissolving the fat that remains on the tongue after eating a fatty sushi topping, cleansing and preparing the palette for the next piece of sushi. This is a task that cannot be performed by beer or Japanese sake.

Then, large teacups became one of the special features at sushi restaurants and a favorite feature among customers, so it wouldn’t make sense to go back to small teacups now. However, times change. There are now sushi restaurants that use relatively small teacups that they change with each refill in an attempt at a sort of stage effect. There are even places that have the teacups imprinted with the restaurant name, phone number, etc. and hand them out to favorite customers. This has tremendous advertising effects.

There are various production sites, but most that are mass-producing are located around the Toki area of Gifu prefecture and the more expensive but also relatively more durable tend to be Arita ware from Saga prefecture. There are wide varieties in shape and pattern, but despite the preference for large teacups at sushi restaurants, there is such a thing as cups that are too big and they are also harder to drink from. Also, thicker cups may be more durable, but they are also harder to drink from. Even when made thick, the rim should be thinner. The cylinder shape is hard to clean and the bottom of the cup tends to be stained by the tea. My personal opinion is that it is hard to find what I would call a refined teacup with a nice color and shape. But the worst is when a thin teacup or tea bowl gets too hot to hold.

Related contents:
GREEN TEA THAT PAIRS WITH SUSHI

What is Matcha?

What are Konacha and Mecha?

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Revision date: October 1, 2022


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How to categorize various types of sushi

a photo of sushiThere are many things that fall under the term “sushi”.

Within Japan, every prefecture has at least one type of local sushi. In order to understand these different types more deeply, we have separated them into categories and will introduce the typical types.

First of all, there should be rules when categorizing things.

However, there are loads of things in this world that seem to have been categorized without any rhyme or reason. The same thing applies to the words used to express sushi categories and types of sushi. This stems from a complete lack of understanding of the history of sushi and how it is made. However, in the end, sushi is food, so there is no academic dissertation on it. Please consider this to be just one point of view when reading the following.

We will first categorize the sushi with clear rules and then introduce individual sushi.

There are various theories regarding the etymology of the word sushi, but the word stems from “su” which is the kanji for “acid” and means “sour”. Initially, “sushi” was used in Japan to refer to Narezushi*, which is eaten with the natural acidity from fermenting salted fish and white rice together. One of the theories is that it started as Sumeshi (‘su’ means vinegar and ‘meshi’ means rice in Japanese) and the “me” was omitted leaving just “Sushi”. Rice is clearly the main attraction in the word and it is thought this word was used to refer to “Namanarezushi**”, which appeared in a time after Narezushi. Although these are only theories, it can only be called Sushi if sour rice is involved. I don’t believe there is anyone who would dispute this fact.

*Narezushi: Mainly made from seafood, rice and salt, allowed to ferment for three months to one year until the rice no longer maintains its shape. Only the fermented seafood is consumed with this type of sushi. Funazushi from Shiga is a famous example of Narezushi.

**Namanarezushi: It is not allowed to completely ferment (fermentation period of two weeks to one month) so both the fish and rice maintain their shapes. This is when sushi evolved from Narezushi, a dish in which the rice was not eaten, to one where the fish and rice were consumed together. Akita’s Hatahatazushi and Ishikawa’s Kaburazushi are famous Namanarezushi dishes.

The historical turning point of sushi was the emergence of what is called Sumeshi (also called Hayazushi because it can be made quickly), in which the sour taste comes from sprinkling vinegar on the rice (acetic acid), rather than the sour flavor from fermenting (lactic acid) at the beginning of the Edo period. It was Sumeshi that really made variations of sushi catch on. At the time there were only Sugatazushi*** and Kokerazushi**** (the original forms of Hakozushi), but after the middle of the Edo period Makizushi, Inarizushi, Chirashizushi and other types started to appear.

***Sugatazushi: Sushi in which Sumeshi is wrapped into a fish that still has its head intact. Tokushima’s Bouze, Wakayama’s Sairazushi, Kumamoto’s Konoshirozushi and Oita’s Aji-no-maruzushi are examples of this.

****Kokerazushi: Kokera refers to thinly sliced seafood and this sushi is made by stacking Sumeshi and ingredients in a container. This can be found today in Osaka and Kyoto in the form of Hakozushi. Examples include Sabazushi and Hamozushi in Kyoto, Battera in Osaka, Oomurazushi in Nagasaki and Iwakunizushi in Yamaguchi.

Let’s dig a bit deeper and divide these into broad categories.

First of all, Sugatazushi and Kokerazushi are still made today as they were long ago. As one characteristic is that Sumeshi is pressed to fix it in place, it can be categorized as a type of Oshizushi.

Chirashizushi was invented in the late Edo period. When eating something like Kokerazushi in which Ingredients are cut and mixed in with Sumeshi, which is then pressed into a box and held down with a weight, it is cumbersome to scoop it out with a spatula. Chirashizushi is made in the same way but omitting the step of pressing with weights. There are various versions of Chirashizushi all throughout Japan.

There was a customer who complained that Sugatazushi always wrapped around the Sumeshi was dull and suggested wrapping the Sumeshi around the fish instead, which led to the idea of Makizushi. However, as the rice was on the outside, it would stick to fingers, so places located near the ocean started to use things like Nori, Kombu and Wakame to wrap it, while places near the mountains used things like pickled leaf mustard. The core also changed from only fish to include things like Tamagoyaki, Kampyo and carrots. These innovations all took place during the middle of the Edo period.

Inarizushi, in which Sumeshi is stuffed inside of sweet, stewed abura-age is a version of Sugatazushi. When rice crops were bad, Okara (soy pulp) was used for the filling instead. When enjoying plays, a favorite pastime of the Edo period, it became a normal occurrence for commoners to take it as a bento. It is said that it infiltrated the masses because Nigiri sushi was outlawed, but the truth is that no one really knows when it was first invented. It’s now spread throughout the world and has evolved into something that looks entirely different and has different fillings.

It is also important to mention that the method of pressing Sumeshi in Kokerazushi was improved to start with rice made into a bite-sized ball, then sticking the fish on top before placing in a box and pressing, which eventually led to the invention of Nigiri sushi.

Looking back on this information, we can see that most of the types of sushi that exist today were invented during the Edo period. Narezushi and similar dishes prior to that seem to be more like methods to make the meat of fish last a long time, rather than sushi in which rice was part of the meal. And Namanarezushi, where the rice was also consumed but ready-made vinegar wasn’t used, is categorized as “Others” when categorizing present-day sushi.

Another difficult one to categorize is the Uramaki version of Sushi rolls. Uramaki is differentiated from Hosomaki, which is a type of Makizushi. However, it has already far outperformed Hosomaki. The reason is that the ingredients used in Uramaki are mostly things that were never used in Hosomaki, and Uramaki allows for a lot of freedom in method. Now there are also versions that don’t use Sumeshi (although they can be left out of sushi categories altogether). In these versions of Uramaki, the ingredients are clearly the main attraction, rather than the Sumeshi. Therefore, they are considered to be evolved from Hosomaki and should be made into one category. Although Makizushi is generally translated as “Sushi roll”, we will consider them separate categories for our purposes.

There is a debate in Japan as to whether Gunkanmaki is categorized as Nigiri sushi or not. The reason is that Nigiri sushi is made by squeezing (nigiri) Sumeshi in the palm of the hand, while this same squeezing process is not as apparent in Gunkanmaki. Makizushi is made by wrapping Sumeshi around ingredients using a Makisu (Bamboo mat), but Gunkanmaki uses no such thing. Even whether or not the process of adding Nori around the Sumeshi for Gunkanmaki is actually wrapping or not is a bit ambiguous, so it’s not clear if it should be categorized as Makizushi or not. However, the issue is only which category it should be added to and it should not be made into its own category. We will consider it a type of Nigiri sushi as the process does include some light squeezing of the Sumeshi.

While we’re on the subject, it is incorrect to call Sashimi and Seafood bowls types of sushi. There is no Sumeshi involved in Sashimi. Seafood bowls also use normal white rice, not Sumeshi. Hopefully you have a better understanding now.

In conclusion, the biggest point in categorizing is whether it is Sushi that uses Sumeshi made with ready-made vinegar (Hayazushi), or Sushi where the sourness comes from fermentation (Narezushi, etc.). Next, in order to further categorize Hayazushi, it is important to distinguish whether similar methods are used to make it and if the Sushi evolved from another, earlier form of Sushi.

Our results are that seven categories are appropriate for understanding sushi better.

1.Nigiri zushi (Nigiri sushi)

2.Makizushi (Maki sushi)

3.Sushi roll

4.Chirashizushi (Chirashi sushi)

5.Inarizushi (Inari sushi)

6.Oshizushi

7.Others

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Revision date: April 15, 2022


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The answer to the question, “Can I eat sushi leftovers the next day?”

a photo of Takeaway sushi

Nigiri sushi is generally made with raw seafood. It can be said that the seafood starts to go bad as soon as it is put on warm rice. Of course, at the stage of preparation, there are procedures being taken to reduce the causative micro-organisms of food poisoning. Out of all food that is commonly eaten raw, sushi is considered to have the least micro-organisms that cause food poisoning.

For example, Vibrio parahaemolyticus, a typically known bacteria that causes food poisoning, attaches to seafood, and if the conditions, such as temperature, are just right, it proliferates at double the speed of other food poisoning bacteria. When you are eating at a sushi restaurant, bacteria growth is being suppressed. However, if you take sushi home to eat it, depending on conditions bacteria could proliferate.

This is why as a basic rule, you cannot take sushi home from a sushi restaurant.

So then, what is the difference between sushi sold at the grocery store and prepared at sushi restaurants?

There are obvious differences between sushi made by sushi chefs and take-out sushi, as explained below.

Take-out sushi is lined up at the store, selected by the customer, then eaten at home, which takes time. Therefore, a higher amount of salt seasoning is used compared to Nigiri sushi restaurants, in order to delay the degradation in quality. Sushi made by sushi chefs at restaurants has a salt content of about 1% in the sushi rice, while that of take-out sushi has about a 2% content.

Next, with a pH of around 4.5%, it is difficult for bacteria such as Salmonella, Staphylococcus aureus, E. coli bacterium bacteria and Vibrio parahaemolyticus to proliferate, and there are experimental results that show they die out. In an experiment that measured the pH of sushi rice in take-out sushi, it was usually measured at 6%. Nigiri sushi made at a restaurant is often around 6.2%, so this acidity is put to good use in the sushi rice and could be delaying degradation.

Furthermore, although it may not be a pleasant topic of discussion, preventing spoiling and deterioration in food caused by micro-organism is done by adding preservatives to improve the shelf life. For example, classic preservatives such as benzoic acid, Sorbic acid and PH adjusters are used all over the world. There is an obligation to list these on the product label when used.

Now let’s get into the main topic.

This all being said, sometimes when you buy take-out, there are leftovers. There is no question that it is better to promptly discard them. But you may think that you can just eat it the next day, right?

You can. And it will taste the same as when you bought it.

First of all, there is something important to remember; not all toppings are equal in take-out. Unfortunately, things that require freshness like shellfish, squid, mackerel and sardines, cannot be saved. These must be consumed on the day they are bought.

Next, let’s go over how to eat your day-after sushi so that it still tastes good.

The toppings this method works for are tuna, salmon, white fish and steamed shrimp. However, the only white fish it works for are benthic fish such as flounder. As long as the meat is still transparent the next day, it’s safe. For Hamachi, which always has more than 20% body fat, which oxidizes, so avoid keeping it to the next day. Raw shrimp is out too. Steamed shrimp becomes more delicious when quickly put into sushi vinegar for storage.

The method is simple!

First, remove the Nigiri sushi topping from the rice. Next, wash that topping with running water for a few seconds and then dry well with a paper towel. Make sure you are quick in all of these steps. Finally, wrap in plastic wrap and store in the refrigerator.

Next, use a wet paper towel to wrap the sushi rice. Wrap this set in plastic and put it in the vegetable drawer if possible. If you don’t have a vegetable drawer than the normal refrigerator compartment is fine.

The next day, when you are ready to eat, heat the sushi rice in the microwave at 1000W for 10 seconds. The point is just to warm it up a little. Next, just take the topping from the refrigerator and place it on the rice. You can add some wasabi if necessary.

Incidentally, if you use this method for take-out sushi, even when consuming it on the same day, it will taste even better than just eating it right away.

The practice of sushi chefs is to put somewhat cold sushi toppings (16~19℃) or room-temperature toppings (20~23℃) on top of sushi rice that is the same temperature of the human body (37℃). We are trying to imitate this method. If you are consuming on the same day, any topping can be removed from the rice and prepared like this.

But please do not wait any longer than the next day to eat any leftovers.

Do not bend this rule. Let me warn you that the symptoms of food poisoning from shellfish and silver-backed fish are horrible. It should also go without saying that if the sushi rice has already dried out, there is no bringing it back, even with this method. Once you’ve reached that point, you just have to throw it away. Naturally, you cannot eat smelly sushi toppings.

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Revision date: April 1, 2022


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A lesson on how the price of Nigiri sushi is determined

In order to prosper, a business wants to sell products at as high a price as possible. So how does a chef determine the price of nigiri sushi?

Naturally, the cost price is what it costs the restaurant for the ingredients while the price on the menu is the selling price. The ratio of these two prices is called the cost rate. In the case of a sushi restaurant, the ideal cost rate is 35% or less. A restaurant operating with only Omakase will have a cost rate of 40% with a focus on the quality of the toppings.

For sushi restaurants, handling of this ratio and the yield are very important. Yield refers to the part of the purchased fish and shellfish that can actually be used. For example, when purchasing a whole fish there are bones, skin, eyes, tail and internal organs that cannot be served as sushi or sashimi. No matter how good a chef is when preparing fish, the bones and skin will remain. In other words, the yield rate is the percentage of parts that can be used as sushi or sashimi. Typical fish yield rates are as follows:

Wild Maguro (Tuna): 65~75%

Buri (Japanese amberjack): 50%

Hirame (Bastard halibut): 40%

Tai (Red seabream): 35%

Akagai (Ark shell): 25%

Mirugai (Keen’s gaper): 20%

The weight of just the topping for a single piece of nigiri sushi is 12 to 18 grams, depending on the ingredients and the policy of the restaurant. The market price for rice is said to be about US$5 per kilogram, and assuming a weight of 15 grams per Nigiri, the rice for a piece of sushi is generally said to cost about US$0.05, including vinegar and salt. Even if you count the shari (sushi rice), soy sauce, wasabi, nori, etc., it’s fair to consider the cost to be about US$0.10.

Now, let’s figure out the price of Hirame, for which 3 kilograms were bought at $60 per kilogram. Assume that the weight of one topping is 15 grams.

The yield rate of Hirame is 40%, so the chef can make 1,200 grams of sushi toppings from 3,000 grams of Hirame. (formula: 3000 g × 0.4 = 1200 g). Since the weight of one topping is 15 grams, 80 pieces of sushi can be made from 3,000 grams of Hirame (1200 g ÷ 15 g = 80 pieces).

Next, we calculate the cost of one topping. Hirame is US$60 per kilogram, so US$180 (US$60×3 = US$180) for 3 kilogram. Since this volume can yield 80 pieces, the cost of one topping is US$2.25 (US$180÷ 80 pieces = US$2.25).

Add the shari price of US$0.10 to this: US$2.25+0.1=US$2.35. In other words, the cost of one Hirame nigiri sushi is US$2.35.

If the ideal cost ratio of 35% is applied here we get 2.35÷0.35 (35%) = US$6.71. For a restaurant serving mainly Omakase, 2.35÷0.4 = US$5.88.

In summary, one piece of Hirame sushi is sold between $5.88 and $6.71.

It may feel surprisingly cheap, but if you perform these calculations with Kuromaguro or Uni, it will be $60 to $90 per piece, and then you’ll feel that it is too expensive. Therefore, the total margin is secured by setting the cost rate for Kuromaguro and Uni to 80-90%, while the cost rate for Saba and Ika is set to 10-20%.

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Revision date: January 6, 2022


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Is the combination of Chablis wine and Japanese oysters match made in heaven?

White wine is generally thought to go well with fresh seafood.

For example, every Frenchman knows that Chablis wine and Belon oysters go together like peanut butter and jelly. The soil of Chablis is made of the stratum that dates back to the Kimmeridgian age and a unique characteristic is that the soil is rich in fossils of small oysters and shellfish. That is why oysters and Chablis wine are said to be the perfect pairing. However, surely there are Japanese people who sense the fishy odor when having Chablis wine and Japanese oysters (Magaki) together. Therefore, some people say that sake is definitely preferred over wine.

The reason for this is that the types of oysters in France and Japan differ.

Famous for its Belon brand name, the oyster native to Europe has a flat, rounded shell. It belongs to the genus Ostrea. To be honest, Belon oysters aren’t sweet and don’t have a distinguished flavor compared to Japanese oysters, and the salty fragrance of the sea is dulled, so it can seem less flavorful.

Meanwhile, the Japanese oyster is elongated and shaped like a raindrop. It is characterized by a smell like it swallowed the whole ocean. This is the main species farmed in Japan. It belongs to the genus Crassostrea. The taste is as if the umami components of the sea have all been concentrated together in one little shell.

Going back to pairing Chablis wine with oysters, it’s common sense in the world of flavors that items with basically similar components pair well together.

The issue lies in how wine is made. Chablis wine contains lactic acid because it is made through forced mal-lactic fermentation. Because it contains this lactic acid, it is partially fighting against the Belon oyster, which has a high glycogen content. In addition, lactic acid is called “warm organic acid”, and it has the property of becoming delicious at warm temperatures. Oysters are eaten cold, so they aren’t good for taking advantage of “warm organic acids”.

Therefore, it can be said that rather than Chablis wine, it goes well with cold organic acid white wine that is delicious when cooled to 7 or 8 degrees, for example, German Franken wine.

So then, what should be done when pairing oysters with Chablis wine?!

If you insist on pairing oysters with Chablis wine, go all out and add squeezed lemon so the citric acid will work to mask the lactic acid and succinic acid, in turn making the wine taste good even when cold. Citric acid is a “cold organic acid” that becomes delicious when cooled, and oysters rich in glycogen go well with “cold organic acid”. Cold acid-based white wine is abundant in the refreshing “cold organic acids” known as malic acid and tartaric acid. Oysters lack this cold organic acid (malic acid and tartaric acid), so adding the citric acid of lemon creates an exquisite harmony.

However, in France there was a time when a disease spread that caused the death of the Belon oyster, nearly rendering it extinct. Therefore, since the Japanese oyster has been transplanted so many times, it is said that nowadays, at least 90% are Japanese oysters hybrids of Japanese oysters.

That means the question remains among Japanese as to whether the combination of Chablis wine and oysters really is a match made in heaven or not. Personally, we’ve never heard of oysters served without lemon, so the fishy smell really isn’t an issue at all in the end.

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Revision date: January 6, 2022


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What is used as a substitute for Madako (Octopus)?

Among the many sushi toppings, Pacific bluefin tuna, and actually the Madai (Red sea bream) as well, are toppings that are difficult for an amateur to tell whether it is farmed or wild. However, there is no need to worry about that when it comes to Tako (Octopus). There are no octopus farms to be found in the world, so it is a 100% wild topping.

In Japan, domestic production isn’t enough to satisfy the appetite of Japanese who like Tako, so the majority relies on imports. Imports from Africa account for 80% and the remainder is imported from China, Southeast Asia, Mexico, Spain and other places in the world.

Most of the African imports are produced by nations on the northwestern coast, with the highest number coming from Mauritania. Until 2003 the highest volume came from Morocco for many years. However, due to continued mass catches to sell to Japan, Tako numbers dropped drastically, leading to the Moroccan government panicking and outlawing fishing. For some reason, Japanese people have grown to love Tako and now consume nearly half of the Tako caught throughout the world.

There are over 200 types of Tako in the world with approximately 60 types inhabiting the seas near Japan. Among these, the Japanese mainly only eat Madako, Mizudako and Iidako. Even among these, Madako makes up at least 80% of consumption.

Most of the Tako found at conveyor belt sushi is African Madako (Madako from Africa). African produced Tako is boiled on-site before being imported frozen. The cost is 20 cents or less per topping.

Amateurs can’t tell the difference between domestic Tako or African imports. However, there is one aspect that even an amateur can use to distinguish between the two. There is one condition for this to work, and that is that at least one of the suckers is in-tact. The suckers are scraped off for most toppings, but in cases where they are sliced by the restaurant, there are often suckers remaining. If the sucker is pure white, it is almost definitely from Africa. Meanwhile, domestic Tako suckers maintain a faint red color in the suckers, even when boiled. The reason the suckers turn white seems to be an effect of the food preservatives added during processing, but this has not been confirmed.

There happens to be a substitute for Madako as well.

One of these is the Iwadako from Vietnam, which grows as large as the height of an adult human. It is imported in frozen slices that can be used as raw Tako as soon as it thaws. The cost of this topping is 20 cents or less per piece. This ends up disguised as Hokkaido Tako.

There are also domestic substitutes. Yanagidako (Chestnut octopus) is mainly caught in the Pacific Ocean, from Chiba prefecture northward. The flavor is lighter than Madako, but it is also softer than Madako, so some people actually consider it to be better than Madako. If it is boiled and made into sushi, an amateur can’t distinguish between it and Madako. The legs are thin so they just need to be cut at an extreme angle in order to make the topping appear bigger. The cost of this topping is 15 cents or less per piece. It is also used as Mizudako because it is watery when eaten raw.

As you can see, there are also many substitute toppings for Madako.

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Revision date: December 21, 2021


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