March, 2023 | Sushiblog－Sushiuniversity

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 Baigai sushi?

a photo of Baigai — Baigai is often used for Tsumami and sushi topping in sushi restaurants.

What is Baigai?

There are several species of shells called Baigai. Among them, the whitish Baigai such as Kagabai (Buccinum bayani Jousseaume,1883), Echubai (Buccinum striatissimum Sowerby,1899), Ooechubai (Buccinum tenuissimum Kuroda in Teramachi,1933), and other whitish Baigai, collectively called Shirobai.

Kagabai lives in depths of 200 to 500 m from the Noto Peninsula to Hokkaido, with shells reaching 15 cm in height, while Echubai (Finely-striated buccinum) is caught in the Sea of Japan west of the Noto Peninsula, at depths of 200 to 500 m, with shells reaching 15 cm in height. Ooechubai (Finely-striated buccinum) is endemic to the Sea of Japan north of Shimane, living at depths of 400 to 1,000 meters, and reaching a shell height of 25 cm. Ooechubai is considered the most delicious of the Shirobai, and the larger the size, the more expensive.

What does Baigai nigiri sushi taste like?

a photo of Baigai nigiri sushi — It is not familiar as sushi topping in the Kanto region, but is often found at sushi restaurants in Kanazawa.

As the name “Shirobai” (Shiro means white) shows, the meat is pure white and shiny like white porcelain. After the characteristic crunchy texture of the shellfish, sweetness and bitterness spread softly in the mouth.

If you are worried about the hardness of the meat in Nigiri sushi, it might be better to taste it as sakamushi (sake steamed). It becomes moderately tender and easy to make nigiri. To enhance the light flavor, you can also boil it quickly in kombu dashi (kelp stock) during preparation.

It is not familiar as sushi topping in the Kanto region, but is often found at sushi restaurants in Kanazawa and other areas. As a side note, from the sound “bai (bai means double)” in Baigai, it is considered a fortunate food, as it doubles the amount of good fortune.

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Revision date: March 22, 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?

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 Dogtooth tuna (Iso maguro)?

a photo of Dogtooth tuna (Iso maguro) — Dogtooth tuna (Iso maguro) is a different type of fish, although it is named tuna.

Dogtooth tuna (Iso maguro) is distributed throughout the tropical and subtropical waters of the Middle and Western Atlantic and Indian Oceans. In Japan, it is distributed mainly in southern Japan and is abundant in the Ogasawara and Nansei Islands. They migrate to rocky reefs and coral reefs, either alone or in groups of several dozen. The total length is around 1.5 meters. Its scientific name is Gymnosarda unicolor (Rüppell, 1838). It belongs to a different group from bluefin, yellowfin, and relatives are not hard to imagine.

It resembles tuna and bonito but is easily distinguished by its wavy lateral line behind the body. It is characterized by the presence of scales only on the pectoral fins and the pectoral carapace around the corselet, and by its large mouth with harp piranha-like teeth.

Its light flesh is slightly softer and less fatty than that of tuna and has almost no acidity. It is easily damaged, has a slight odor, is not very tasty, and is not marketable. It is known more as a fishing target than as a food source. It is known more for its speed and pulling power than the Caranx family. Large Dogtooth Tuna can cause ciguatera poisoning, so be careful. This fish is often sold canned or frozen.

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Revision date: March 16, 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 Sakhalin taimen (Itou) sushi?

a photo of Sakhalin taimen (Itou) — Sakhalin taimen (Itou) is known as the fish that anglers dream of encountering only once in their lives.

What is Sakhalin taimen (Itou)?

Sakhalin taimen is distributed only in the southern Kuril Islands, Sakhalin, Primorsky Territory, and Hokkaido. It used to be distributed in Lake Ogawara, Aomori Prefecture, but has already become extinct. In Hokkaido, it inhabits gently meandering rivers in the Konsen Plain, Sarufutsu Plain, and Sarobetsu Plain.

Reaching a maximum height of 2 m, it is the largest freshwater fish distributed in Japan. Its Japanese name is Itou and its scientific name is Parahucho perryi (Brevoort, 1856).

The body color is light purple or light green on the back side and silvery white on the belly side. Unlike other salmonids, Sakhalin taimen lay their eggs in the spring and do not die, but instead lay them over and over again for many years. Females are usually larger than males, sometimes twice as large as males. The “魚鬼” Chinese character combines “魚” (fish) and “鬼” (devil). As the Chinese characters suggest, it is known for its ferocious nature.

It is also farmed in Aomori and Niigata, but because it takes 5~6 years to grow to 50 cm in length, it is not commercially available and is used at hotels and other places as a regional specialty.

What does Sakhalin taimen (Itou) sushi taste like?

a photo of Itou nigiri — If you find Itou nigiri sushi, you should definitely eat it because you may never get a second chance.

Its flesh is not peculiar and is a slightly pale orange color. The texture is tender but strangely does not feel tender and melting. It is rarely served at sushi restaurants in Tokyo, but it is probably farm-raised Sakhalin taimen. Whether or not it is a natural product, it is a very rare topping, so if you find it, you should definitely try it.

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Revision date: April 3, 2023

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What is Noresore sushi?

a photo of Noresore — It is called different names depending on regions: “Berada” in Okayama Pref., “Tachikurage” in Misaki, “

What is Noresore?

Noresore is believed to be a juvenile of the Anago, but the species’ name is not really known. The larvae of Unagi (Japanese eel), Anago (Japanese conger), and Hamo (Daggertooth pike conger) are called Leptocephalus and are elongated and flattened, leaf-like in shape. They are transparent to the muscles and spine and are 5~6 cm in size. This is called Noresore in Kochi Prefecture. It arrives at the market from February to May, but the quantity is small and the freshness fades quickly, so the price is always high.

Many people look forward to it as a delicacy in early spring. Indeed, the smooth slurping and subtle sweetness are something special that cannot be tasted anywhere else. When eaten raw, it goes well with ginger soy sauce, wasabi soy sauce, or ponzu (Japanese citrus juice).

a photo of Noresore sushi — Noresore is served in a Gunkan maki. However, it is rare for it to be served as sushi.

What does Noresore sushi taste like?

When made into sushi, it is served with green onions and ginger as condiments, and in a Gunkan maki. The atmosphere is similar to that of Shirauo (Japanese icefish), but it is much more slippery to the palate, much like the high-end Gelidium jelly. In Tokyo sushi restaurants, it is sometimes served as Tsumami, but almost never as Nigiri sushi.

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Revision date: March 11, 2023

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What is Sea squirt (Hoya) sushi?

a photo of Sea squirt (Hoya) — Sea squirt (Hoya) is said to be unique in that it has all five tastes humans are able to detect – sweet, sour, salty, bitter, and umami.

What is Sea squirt (Hoya)?

Sea squirt (Its Japanese name is Hoya) is thought to be a specialty of the Tohoku region, but it is distributed from Hokkaido to Honshu, Shikoku, and Kyushu, as well as from the Korean Peninsula to the Shandong Peninsula of mainland China.

It has red, hard skin and protruding warts, the tops of which have entry and exit holes, and lives attached to rocks and other objects on the seafloor.

The sea squirt is nicknamed the pineapple of the sea because of its resemblance to a pineapple, which is not clear whether it is an animal or a plant. It is a close relative of vertebrates, although it is not at all imaginable. Its size is about 20 cm.

The two main species of Hoya (海鞘、老海鼠) consumed in Japan are Ma-hoya (Halocynthia roretzi (Drasche, 1884)) and Aka-hoya (Halocynthia aurantium aurantium (Pallas, 1787)). Miyagi Prefecture accounts for about 80% of the nation’s production, while Aka-hoya is mostly produced in Hokkaido.

What does Sea squirt (Hoya) nigiri sushi taste like?

a photo of Hoya nigiri sushi — Sea squirt (Hoya) has a complex taste with a mixture of bitterness and sweetness.

Its edible parts are the muscles and internal organs, which are removed by peeling the skin. Hoya’s gonads get fatter in the fall and its muscles become leaner. Then, after May, the meat gets fatter and has eight times more glycogen than in winter, making it tastier and sweeter. If the body color of Ma-hoya is pineapple color, Aka-hoya is the color of a persimmon seed that has fully ripened to bright red.

Sea squirt takes in a lot of seawater, so it has a strong smell of the sea anyway. It also has a unique umami and bitter taste because it is rich in amino acids such as glycine, alanine, Taurine, proline, and glutamic acid.

Ma-hoya is generally considered to have a stronger flavor, while Aka-hoya is relatively mild. After a few hours of fishing, a kind of gasoline smell is produced, giving the sea squirt its distinctive aroma. For this reason, it tends to be avoided by first-timers, but many people become addicted to it once they have tasted it. It is also a dish that makes sake go down a treat.

The fresh sea squirt meat is so elastic that it bounces back. The fish is then cut into small pieces with a decorative knife so that it is soft but still crisp. For condiments, we recommend using asatsuki chives, grated daikon and chili, and ponzu (Japanese citrus juice) soy sauce. Ma-hoya is not for everyone, but it can be enjoyed as an unusual sushi topping.

To enjoy the aroma of the sea, eat it raw with wasabi soy sauce or vinegared food. It goes well with cucumber as an accompaniment. Besides, it can be simmered, grilled with miso, deep-fried, or salted.

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Revision date: August 10, 2024

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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 real Omakase at a sushi restaurant?

Omakase sushi experience — She is very interested in eating sushi toppings for the first time.

We’ll start by breaking down the meaning of this word in Japanese.

The “O” of “Omakase” is a prefix generally used as an honorific expression. The meaning of “makase” refers to a judgment of things and means to entrust a task you were meant to do to someone else, allowing them to perform the task at their own discretion. In terms of sushi, while a customer normally chooses which toppings they want to eat on their own, a customer with limited sushi topping knowledge may ask the chef to prepare his own recommendations.

There are various other ways to order sushi toppings as well. First, sushi restaurants generally have a set menu called “Okimari.” For example, let’s consider an Okimari set that contains 8 pieces of nigiri sushi. This set of 8 pieces will contain the same toppings and maintain the same price throughout the year. In contrast, a customer may choose the number of toppings they like in whatever order they prefer, such as ordering two pieces each of four types of toppings, which is called “Okonomi.” They can even order eight of the same topping. The price for “Okonomi” depends on what is ordered, the more expensive the toppings are, the higher the price will be. For “Omakase,” the chef would select 8 toppings and serve them in his recommended order. However, the customer conveys their budget to the chef in advance so the sushi course can be provided within that budget. The customer can also specify toppings they prefer to avoid. In other words, you need to let the chef know in advance about your budget according to the market, and any requests (For example, I would like to eat the Splendid alfonsino (Kinmedai) in season) that you can’t budge on. You don’t need to leave those two things up to the chef’s discretion.

Now, in actuality, there are many sushi restaurants that stray from the original definition of “Omakase.”

For instance, he/she may include Tsumami as part of the course, rather than only sushi. This would be Sushi Kappo (sitting at the counter to enjoy Japanese food and served directly by the chef). A sushi restaurant was once a place where only Nigiri sushi was served. To explain in more detail, if only Nigiri sushi is served, then even if you were to eat 20 pieces of Nigiri sushi, your time in the restaurant would only be around 30 minutes (this is true the case of the establishment of the famous Jiro). Nowadays sushi restaurants are used for entertaining business clients or going on dates, so the customer may stay for around two hours. In situations like this conversation is the priority, so the actual ordering of the sushi takes the backseat. Incidentally, the practice of drinking Japanese sake at sushi restaurants is said to have begun around 1910.

Next, we’ll let you in on a common misconception that you probably don’t want to hear.

Apparently, people believe that ordering Omakase means that you will be served rare pieces that are not disclosed on the menu. Some are even convinced that they can get more expensive toppings than they would if they ordered with the Okonomi method. However, the restaurant just sets the price for the Omakase course and just adjusts the menu items accordingly (to suit the budget) based on current stock. The benefit to the restaurant is that it only stocks the amount of seafood necessary and will waste less. Unfortunately, rare finds are reserved for customers who know what they like. Go ahead and toss any such expectations out of your mind right now. Instead, acquiring sushi knowledge will allow you to avoid being recommended toppings that are approaching expiration.

Finally, if you just get an expensive Omakase course without understanding where the toppings came from or when they are in season, then it won’t contribute to your deeper understanding of the magnificence of Nigiri sushi.

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Revision date: April 18, 2023

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