What are the important points when using ice to kill small fish?

a photo of Korijime
the general practice for small fish is to kill them all together with cold seawater using Korijime.

When it comes to large volumes of small fish like Aji and Iwashi, it’s impossible to use Ikejime for each individual fish. Therefore, the general practice for small fish is to kill them all together with cold seawater using Korijime (“kori” is the Japanese word for “ice”).

Here we will explain the important points of Korijime.

The ice is important to maintain freshness. However, this does not mean that more ice is better. The amount of ice used must be adjusted depending on the state of the fish. When Ikejime is performed on live fish and then the fish is put directly on ice, it is killed too early. Also, if ice is only applied to certain parts, only that part will cool, changing the color of the meat. So, rather than directly cooling fish that haven’t yet reached rigor mortis after death, the environment around the fish is cooled.

On the other hand, the fish that have been killed lose their freshness quickly so plenty of ice is applied then in order to prevent changes in the temperature of the fish’s body. Although plenty of ice is necessary, ice is heavy so using so much that it would leave indentations on the fish’s body would be inexcusable. You can tell whether the fisherman is used to handling the fish depending on how much ice is used.

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Revision date: February 4, 2023

What is sashimi?

a photo of sashimi
A plate of assorted sashimi

Sashimi is made by removing the inedible head, bones, skin, fins, and tail from raw fish, etc., and cutting them into small, easy-to-eat pieces.

It is considered the ultimate washoku dish, but why is such a simple and uncooked dish regarded so highly? In Japan, ingredients that are fresh enough to eat raw are considered more valuable, and sashimi preparation in particular requires substantial labor and technique.

Its preparation begins when the fish is first taken out of the sea. The fishermen perform Ikejime, a technique that shuts off the fish’s neurotransmission in order to preserve freshness and texture while the fish matures.

Each fish has its peak, which is referred to as shun (season), and chefs train for years to develop their ability to determine whether a fish is fresh and its peak. The carefully selected fish is cut into smaller pieces in one stroke with a sashimi boucho (knife), which creates a smooth surface. If the meat is cut with an unsharp knife, it will be crushed and the result will be watery and tasteless.

The chefs pursue pleasing texture, ease of eating, and delicious flavors by varying the thickness of cuts and cutting techniques, depending on the type of seafood they work with.

It is popularly served with soy sauce and condiments such as wasabi, and such garnishes as shiso and shredded daikon radish.

As an aside, sushi restaurants offer a variety of sashimi cuisine. You can order them as assortments, not to mention as single dishes of tuna, sea bream, squid, horse mackerel, or shellfish among others. If the shop has seasonal fish in stock, it might be a good idea to leave your order to the chef.

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Revision date: February 3, 2023

What is Longtail tuna?

An illustration of longtail tuna
An illustration of longtail tuna (© 2023 – Fishing Spots)

Longtail tuna inhabits continental shell and ocean waters in warm temperate and tropical regions of the Ind-west pacific. The dark blue-backed fish is recognized by their short pectoral fins and slender body. Its tail is long compared to other tuna. It is also distinguished by the presence of elongated, colorless spots on the underside and belly, between the pectoral and anal fins. As the name suggests, it is characterized by a rather long tail from the tail fins to the tail.

It reaches a maximum length of 1.5 m and up to 32 kg in weight. It is caught by longline fishing in Southeast Asia and Australia.

The Japanese name is Koshinaga maguro (腰長鮪). It is caught in small numbers in Kagoshima, Nagasaki, and Okinawa prefectures, but its numbers are small and it is the least caught species of the tuna genus, so it is traded only in its place of origin and rarely appears on the market. In addition, juvenile tuna look similar to bluefin tuna, yellowfin tuna, and albacore. Therefore, they are sometimes confused in the market.

In northern Kyushu and Sanin regions where bonito are not caught, however, it is an autumn treat. Most of its flesh is red meat, and its taste is refreshing so it is eaten as sashimi. However its fat is not sweet and has little acidity, so it is not suitable for nigiri sushi. In Australia and Southeast Asia, it is eaten as steak or sauteed.

Its scientific name is Thunnus tonggol (Bleeker, 1851).

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Revision date: February 2, 2023

What is Blackfin tuna?

An illustration of Blackfin tuna
An illustration of Blackfin tuna (Image credit: Duane Raver Jr.)

Blackfin tuna is one of the smallest members of the species of Tuna belonging to the genus called Thunnus and family of Scombridae. The English name blackfin tuna comes from its black pectoral fins and other fins. It is known by various interesting names like Blackfinned Albacore, Bermuda and football due to its typical football like appearance.

The Japanese name is Taiseiyou maguro (大西洋鮪). There is also a species called Taiseiyou Kuro-maguro (Atlantic bluefin tuna,) which is very confusing. It is not distributed in the Japanese market.

The range of distribution of these tuna is restricted as they can only be spotted in the West Atlantic Ocean, encompassing the Gulf of Mexico, southern Brazil and the Caribbean Sea. This is unique for a species of Tuna to have a limited range but it probably has something to do with the Blackfin Tuna’s preference to migrate to temperate waters above 20℃. It is especially common in the Gulf of Mexico, where it is a favorite target of sports fishermen.

It can be identified by a dark-blue to black stripe across its back usually with a golden hue under it and a silver belly. It is the smallest in the Tuna family reaching lengths of about 1 m and weight of 20 kg. It is at its peak during autumn, winter, and spring in Florida Keys. Only 0.4 tons per year of blackfin tuna is caught in the world.

Though it doesn’t quite measure up to world-class bluefin, yellowfin or bigeye tuna in food value, it is very good in its own right. The top preparation method with fresh blackfin is undoubtedly sushi or sashimi, as it yields an incredible flavor and texture when raw, but it also excels on the grill or is seared over high heat. It also makes a delectable tuna salad.

Its scientific name is Thunnus atlanticus (Lesson, 1831).

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Revision date: February 2, 2023

What is Gastoro?


a photo of Gastoro
Image credit: © Copyright National Research Institute of Far Seas Fisheries, Japan Fisheries Research and Education Agency

Gastoro is widely distributed throughout the temperate and subarctic regions of the Southern Hemisphere, but is not known to be found in the Northern Hemisphere. It is found in the open ocean around Australia and New Zealand, at depths of about 200 meters. It has the English name “Butterfly Tuna (Gasterochisma melampus Richardson, 1845)” because of its large, butterfly-like abdominal fins.

It is mostly caught as bycatch in longline fisheries that catch southern bluefin tuna. This is due to the overlap in habitat with southern bluefin tuna.

It is often thought to taste similar to tuna, a popular sashimi fish, perhaps due to the inclusion of maguro and tuna names in its name, such as “Uroko maguro” and “Butterfly tuna,” but it actually does not resemble tuna very much.

It has a refreshing flavor more like swordfish tuna. The best way to eat it raw is marinated with soy sauce, which takes about 15 minutes for the whole saku (fillet).

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Revision date: January 28, 2023

What is Himokyu-maki?

a photo of Himokyu maki
Himokyumaki (Hosomaki) using the mantle of ark shell and cucumber as fillings.

Edomae sushi rolls are made with grilled nori. In Tokyo, this is called nori-maki. Himokyu-maki is norimaki filled with Akagai mantle wrapped in. The mantle has a stronger sea smell and slight bitterness than the Akagai body itself, and some people actually prefer the mantle. The crunchy texture and umami bring out maximum harmony with the refreshing fragrance and texture of the cucumber. This is a true nori-maki masterpiece. Make sure to give it a try when Akagai is in season.

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Revision date: January 27, 2023


What is Tazunamaki?

a photo of Tazunamaki
Tazunamaki made by long-established Kizushi (㐂寿司)

In general, Tazunamaki (手綱巻き) refers to thinly sliced sayori, shrimp, kohada, and omelets, arranged diagonally and rolled with sushi rice. It is called Tazunamaki because the surface of the diagonally arranged finished product looks like the pattern of a horse’s reins.

The ingredients used for Tazunamaki are almost always fixed, and the four main colors are: red from the shrimp, silvery white from the sayori or kohada, green from the cucumber, and yellow from the omelet. As a precaution in preparation, the sayori should be used after a quick wash in salted water, or furthermore, it should be kobujime (salted or vinegared fish marinated between sheets of kelp). Cucumbers should also be slightly wilted in salted water to help them adhere to the sushi rice.

On the other hand, Tazunamaki made by sushi chefs, consists of kohada and kuruma prawns rolled alternately on a bed of sushi rice. This seems like Kansai’s oshizushi, but it is another old Edo-style work (Edomae shigoto).

The balance between the sweetness of the shiba shrimp oboro and the sourness of the kohada is wonderfully balanced, and the taste is so delicious that one can never get tired of it no matter how many times one eats it.

Related contents: Kizushi Tazunamaki

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Revision date: January 25, 2023

What is Chawan-mushi at sushi restaurant?

a photo of chawan-mushi
It is typically topped with Kamaboko, Shiitake mushrooms, Ginkgo nuts, and shrimp.

Chawan-mushi (Savory steamed egg custard) is made from eggs and dashi (soup stock) and garnished with shrimp and ginkgo nuts. It is steamed in a cup and often served as a cold or hot appetizer. It is a standard item at the sushi restaurant.

Unlike other egg custard, it is not sweet but it has a savory flavor packed with umami from dashi and topping ingredients. It is velvety feeling on the palate is irresistible.

Then why do sushi restaurants serve chawan-mushi?

That is because sushi is a cold dish, so they basically serve something warm as a garnish.

Another reason is that the ingredients used for chawan-mushi, such as shrimp, shiitake mushrooms, eggs, and kamaboko, are either used daily at sushi restaurants or are readily available at market stores that sell sushi items.

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Revision date: January 20, 2023

How to eat soups

a photo of eating soup
How to eat shirumono which is soup in a bowl.

A sushi meal is often completed with clear soup or miso soup. Interestingly, the ingredients in the soup differ depending on the sushi restaurant or the day.

Put all four fingers of your left hand under the bottom of the bowl and place your thumb, gently on the rim. The key is to smell the aroma first. Next hold the rim of the bowl right up to your mouth, and do not make any slurping noises. Then eat between the soup and the ingredients alternately.

When asked “could we serve you a soup bowl now?” at a high-class sushi restaurant, it sometimes is a sign that Omakase course is about to end. If there are any additional sushi toppings you would like to eat, this is the right time to order. And occasions like having a client dinner imply that your meal has reached the budget you informed in advance.

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Revision date: January 19, 2023


What is Futomaki?

A photo of Futomaki
Futomaki contain multiple ingredients.

Sushi made by spreading vinegared rice on a sheet of dried laver and rolling it up with ingredients is called “Makizushi” in Kansai and “Norimaki” in Kanto, and the two are basically the same.

In Kanto, sushi rolls are distinguished by their thickness as “Hosomaki (thin rolls),” “Nakamaki (medium rolls),” or “Futomaki (thick rolls),” but in Kansai, the term “Makizushi” often refers to “thick rolls.

Hosomaki, such as Kanpyomaki (Dried Gourd Shavings Sushi Roll), Tekkomaki (Tuna roll), and Kappamaki (Cucumber roll), generally contain only one type of ingredient, while Futomaki (太巻き) contains multiple ingredients such as kanpyo, tamagoyaki, shiitake mushrooms, and cucumbers.

The size of the nori used differs depending on the thickness of the roll. Hosomaki uses a sheet of nori cut in half, Nakamaki uses one half to one sheet of nori, and Futomaki uses one or more sheets of nori. The basic size of nori is 21 cm in length and 19 cm in width per sheet, and each sheet weighs about 3 g. This size is called “Zenkei”.

The filling and hearty Futomaki satisfies your appetite. It has a slight sweetness, intricate flavors, and pleasant textures. Everything appealing about sushi is packed into a roll of Futomaki.

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Revision date: January 16, 2023

Do you know what kind of Tuna you’re eating at a sushi restaurant?

a photo of bluefin tuna
Bluefin tuna in the fish market

There are eight types of tuna fished in the world: Pacific bluefin tuna (T. orientalis), Atlantic bluefin tuna (T. thynnus), Southern bluefin tuna (T. thynnus maccoyii), Bigeye tuna (T. obesus), Yellowfin tuna (T. albacares), Albacore (T. alalunga), Blackfin tuna (T. atlanticus) and Longtail tuna (T. tonggol).

According to 2019 statistics, approximately 2,280,000 tons of 8 types of tuna were caught that year. Of those, only 1.6 tons per year are Pacific bluefin tuna. Atlantic bluefin tuna only reaches 3.1 tons per year. Southern bluefin tuna is 1.7 tons per year. Yellowfin tuna is 1,579,000 tons per year. Bigeye tuna accounts for 392,000 tons per year. Albacore is 245,000 tons per year. There is some fluctuation from year to year, but the data has remained pretty stable over the past 20 years, except for the Yellowfin tuna. Blackfin tuna catch is extremely how and is not found at sushi restaurants as a topping except Florida. Longtail tuna is no more than a by-catch of other tuna and is the least caught species in the tuna genus.

Of these eight types, the six types used as Nigiri sushi toppings include Pacific bluefin tuna, Atlantic bluefin tuna, Southern bluefin tuna, Bigeye tuna, Yellowfin tuna and Albacore.

We have attempted to lay them out here in order of price. Incidentally, the unit price for Bluefin tuna is more than ten times that of Albacore.

an illustration of Distribution map of Pacific bluefin tuna
Distribution map of Pacific bluefin tuna

The statistics categorize Pacific bluefin tuna and Atlantic bluefin tuna separately, but Japanese sushi restaurants do not distinguish the two. In other words, the menu does not read “Pacific bluefin tuna”. Not only that, the menu actually only lists “Tuna,” so in that case you can assume it is either Bluefin tuna, Southern bluefin tuna or Bigeye tuna.

an illustration of Distribution map of Atlantic bluefin tuna
Distribution map of Atlantic bluefin tuna

Those in the industry at the Toyosu Market refer to Atlantic bluefin tuna as “Jumbo”. This is the nickname for Tuna imported from Boston and Ireland into Japan. This also makes it clear that it is not the Pacific bluefin tuna fished in Japan’s local sea waters. Southern bluefin tuna is mainly caught in the Indian Ocean and flash-frozen to negative 60℃ before being distributed all over the world. The majority of Bigeye tuna, Yellowfin tuna and Albacore are also frozen and distributed.

When the Tuna a sushi restaurant is serving is Bluefin tuna, the chef wants to emphasize that, so he or she may drum up conversation with, “We got some good Bluefin tuna in today.” Incidentally, Bluefin tuna is also called “Hon-maguro”. In Japanese “Hon” is short for “Honto,” which means “Real.” In other words, this implies that other Tuna is not the real thing.

a photo of Yellowfin tuna
Yellowfin tuna in the fish market

Yellowfin tuna is generally served at Kansai sushi restaurants, but not at Tokyo sushi restaurants. This is due to differences in Kansai and Kanto food cultures. The Ahi often consumed in Hawaii is Yellowfin tuna. Tuna caught in the inshore waters of Micronesia is either Yellowfin tuna or Bigeye tuna.

a photo of bigeye tuna
Bigeye tuna in the fish market

Yellowfin tuna and Bigeye tuna are often used for take-out sushi. If Bluefin tuna is used, this will be indicated with a label on the package making it clear that it, “Includes Bluefin tuna.” That is how expensive and delicious Bluefin tuna is. However, in this case you can be sure that the Bluefin tuna came frozen and was farmed. Also, depending on when it was fished, the akami (red meat) of the Bigeye tuna caught in the inshore of Japan are nearly on-par with the akami Bluefin tuna. Bigeye tuna is the most-consumed Tuna as Sashimi in Japan.

a photo of Albacore
Albacore in the fish market

Albacore is often served at conveyor belt sushi. Bintoro is especially popular. Bintoro is the name for the Toro part of Albacore. The meat is whiter than that of Bluefin tuna and the fat is known for being lighter.

In conclusion, you may have never been aware of the types of Tuna consumed at sushi restaurants. The types of Tuna that go better with spicy sauces are generally Yellowfin tuna and Albacore. For the same reason, Yellowfin tuna and Albacore are often used in Sushi rolls. But when made into Nigiri sushi, you can’t help but to be conscious of the type of tuna because the flavor and aroma are apparent. Also, when Bluefin tuna is served raw, you can expect top-level fragrance.

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Revision date: January 11, 2023

What is Moshio?

a photo of moshio
Natural salt with a pleasant taste

The “Mo” of “Moshio (藻塩)” means “seaweed (海藻)” and “shio” means “salt (塩).” The only ingredient in Moshio is Hondawara, a type of seawater and seaweed. It is also called Mojio.

The way it is made is extremely primitive. First, Hondawara (Gulfweed), etc. is soaked in seawater then wrung out and dried multiple times over 2 to 3 days. This creates a brown-colored seawater infused with the umami and color of Hondawara. In the end, Hondawara is dried and grilled, then the charcoal ash is mixed with the seawater infused with the umami and color. This is left for a day, where the ash naturally sinks to the bottom, completing the dark-brown seawater. Moshio is made by boiling down this seawater. This is said to be the origin of salt-making far longer ago than the manufacturing method of using salt farms.

According to a sushi chef at a Michelin Star restaurant, there are two types of Shari and each will either bring out the best of either Akami or the Shiromi. When pursuing ideal Shari to go well with a variety of toppings, this chef happened to come across Moshio. This led to a lot of trial and error, and eventually he came up with a fully universal type of Shari. Perhaps switching to Moshio is a good idea.

It is characteristic in that there is no sharp spiciness and it has a very mellow flavor, so it brings out the taste of the elements of seafood, etc. The color is a light beige and the salt can be called a concentration of umami made from nothing but seawater and seaweed.

Related contents: Nikkei Style

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Revision date: January 7, 2023

What is Venerupin?

a photo of oyster As this is an extremely lethal toxin, there are reports of cases of poisoning in some types of oysters and Asari (short-necked clams). The source of the Venerupin is said to be the intake of toxic dinoflagellate. This only occurs in early Spring in Nagai, Kanagawa prefecture and Lake Hamana in Shizuoka prefecture and in one instance over 100 people died. However, as there have been no incidents of poisoning since 1950, it’s still not clear if the shellfish actually become toxic or not.

In most cases, the toxic symptoms appear within one to two days and start with abdominal pain, vomiting, constipation, etc., followed by blood spots on the skin and bleeding from the mouth and nose. Liver function also significantly decreases and the patient suffers from mental derangement. They then fall into a coma and die within a few days.

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Revision date: January 5, 2023

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

What is another Kaiseki Ryori?

a photo of Kaiseki RyoriThere are two types of Kaiseki Ryori (懐石料理・会席料理). Both are course meals and have the same reading, but they are expressed in different Chinese characters and the contents are quite different.

In this case, Kiseki (懐石) means a poor meal enough to survive hunger from the anecdote that a Zen priest held a warm stone in his robe to forget the cold and hunger during his training. It consists of soup, rice and three dishes to prepare your stomach before enjoying the strong tea served at the tea ceremony.

As explained earlier, the basis of Kaiseki Ryori at a tea ceremony is one soup and three dishes, but Japanese restaurants, where you are likely to go to eat in person, often have their own arrangements, such as increasing the number of items or changing the order. In a typical menu, oshiki (折敷), wanmono (椀盛), grilled dishes (焼き物), simmered dishes or vinegared dishes (強肴), suimono (吸い物), hasun (八寸), yuto・kouomono(湯桶・香の物), and omokashi・koicha (主菓子・濃茶) are served.

Originally, Kaiseki Ryori was not a sumptuous meal to be eaten with sake, but rather a dish to fill a small stomach before enjoying a more delicious cup of tea.

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Revision date: December 30, 2022