Hirame isn’t thought of as a high-end fish in the US!?

Hirame is a high-quality fish that goes for at least US $50 per kilogram. It can even exceed US $80 per kilogram, depending on the timing and the fish’s body. Hirame is a typical white meat fish when winter is approaching and a great sushi topping to start off a meal. Also, the taste is so delicate that the original flavor can be cancelled out just by adding too much soy sauce. How the chef expresses this delicate taste is a tribute to his skill and something that foodies look forward to.

In the US, Hirame is often written as “halibut” on the menu of sushi restaurants. Technically the English name of Hirame is Bastard halibut. Hailbut (referring to Pacific halibut) is called “Ohyo” in Japanese. In Japan, the engawa of massive Ohyo is often used as a substitute for Hirame engawa at conveyor belt sushi, but the two are not confused for each other. There is no mistake that Hirame is related to halibut, but they are completely different species. Incidentally, the price of Ohyo is US $3 to $20 per kilogram. It is incomparably cheaper than Hirame.

Also, depending on the restaurant it may be represented in a variety of other ways such as fluke, flatfish and flounder. These terms refer to relatives of Hirame (鮃) or Karei (鰈), but do not indicate any certain species of fish. In other words, there is generally no distinction between Hirame and Karei in the US and to go even further, all white fish are thought to be the same species.

The delicious taste of fish is dependent on the distribution of fat and the amount of inosinic acid. Therefore, fish taste better in the seasons when they have fattened up. On the other hand, people have a hard time distinguishing between types of fish when comparing the tastes of the parts with less fat. The free amino acids in fish meat differ only slightly between different types of fish. In other words, the flavor of all fish is mostly the same. It is only the amount of fat and the amount of the umami component, inosinic acid, that differ between fish, so apparently even sushi chefs cannot distinguish between fish just by eating the back part, which has a low fat content.

This is part of the reason why in the US all white fish is all lumped into the same category and to top it off, the common consensus there is that white fish has no flavor.

At sushi restaurants in Japan, generally there are at least two types of white fish on offer. It is practically guaranteed that Hirame will be in stock in winter. The light flavor unique to this white meat that spreads with each bite maximizes the aroma and sweetness of the vinegared rice. Recently, white fish with high levels of fat such as Kinmedai and Nodoguro, have become standard, high-quality white fish.

The difference between how even these sorts of white fish are handled in the US and Japan is astonishing. That said, flavorless Hirame is not consumed as sashimi or sushi even in Japan. It is served in dishes with strong flavors, like carpaccio. It’s possible that delicious Hirame is just not available in the US.


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Revision date: October 7, 2021

What is Ishigakigai sushi?

Ishigakigai is a shellfish found from Kashimanada northward, Hokkaido, from the Kuril Islands to the Aleutian Islands and even on the west coast of North America. It lives off of plankton in the shallow sandy mud bottoms of the sea at depths of about 50 meters.

Aquaculture in Hirota Bay, Iwate Prefecture, has been successful and it started to appear at the Tsukiji Fish Market starting in about 2008, distributed as Ishigakigai. According to brokers, someone in the business at Tsukiji Fish Market misheard “Ishikage” as “Ishigaki” and the name stuck in the market. While Torigai meat looks black, Ishigakigai looks whiter, so it is also called “Shirotorigai”. The official name is “Ezoishikagegai”.

It starts to become common at the market when the Japanese rainy season ends, at the beginning of summer every year, which is around the end of the Torigai season. It then disappears from the market at the end of summer. A number of sushi restaurants start using it as a substitute for Torigai all at the same time, so Ishigakigai nigiri sushi suddenly started appearing on menus. Frankly, it is somewhat conservative as a nigiri topping but is known for the crunchy texture when biting into it. It also has strong sweetness and umami, which goes exquisitely with Shari. The sushi chef slaps the meat in his hand directly before serving to stiffen it–a way to increase the crunchy texture characteristic of shellfish. Naturally this texture is evidence of its freshness.

As the season of availability is short and the production sites are limited, Ishigakigai often fetches a high price. Those up for sale at the Toyosu Market go for $2 to $4 each. Wild-caught Ishigakigai is rarely found on the market, but when they are, the price is double that of the farmed version.

A relative of the Torigai, the Ishigakigai is rich in amino acids such as taurine, glycine and arginine. It is also resilient and can live for days, even outside its shell.


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Revision date: October 5, 2021

There are strangely two types of Ama ebi

It goes without saying, that each type of fish has its very own scientific name. However, in places like the Toyosu Fish Market, there are seafoods that end up sharing a name.

The official Japanese name of ama ebi (sweet shrimp) is “Hokkoku Akaebi” (scientific name: Pandaluseous Makarov). In Japan, ama ebi lives naturally along the Sea of Japan coast and the coasts of Hokkaido, and the ama ebi sold at Toyosu market is caught from Toyama prefecture and northward to Hokkaido and southward. When made into nigiri sushi, it is harmonious with the acidity of the vinegared rice and the thick sweetness is irresistible. It really lives up to its “sweet” name.

However, what dominates the Toyosu Market is frozen shrimp of the same pandalidae family, called “Honhokkoku Akaebi” (scientific name: pandalus borealis kroyer) from Iceland and Greenland. This is distributed as “Ama ebi” at the market, but strictly speaking it is a different type of shrimp. As far as appearance goes, it is impossible to tell the difference and they say that even the flavor is the same.

The majority of ama ebi used at conveyor belt sushi is produced in Greenland and imported to Japan through China. The reason for this import circumvention is that the processing to turn the shrimp into ready-made sushi toppings is done using inexpensive labor in China. The frozen ama ebi is thawed in China, processed (head, shell, etc., are removed) and then frozen again. Of course, this process diminishes the freshness of the fish. Preservatives are used to help prevent this. For example, pigment fixing agents are used in order to reduce discoloration from fading. Furthermore, acidity regulators and antioxidants are used to prevent changes in the quality and color of the meat. Ama ebi is stored in packs of 50, imported en masse to Japan, and can be used for sushi or sashimi immediately upon thawing.

As this ama ebi caught in the North Atlantic Ocean is considerably cheaper than domestic ama ebi, the reality is that conveyor belt sushi wouldn’t survive in Japan without these imports.


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Revision date: September 1, 2021

Where does the name “battera” come from?

While not often seen in Tokyo, “Whole mackerel sushi” is popular in Kyoto and Osaka. This is pressed sushi made by placing vinegared saba (mackerel) on top of sushi rice and shiroita-kombu (kelp that has been lightly shaved down) on top of that, and is normally called “battera” in Kansai.

It would make sense to call it saba pressed sushi, but a customer actually came up with this weird name, “battera”.

Around 1890, there was an exceptionally large number of konoshiro (gizzard shad) fish for the year. A sushi restaurant took notice of the cheap konoshiro, butterflied it, made it into fukin-jime, then sold it in this shape that resembled a boat. Apparently it used to look more like a boat than the present-day battera.

As the Portuguese word for “boat” is “batela”, someone started ordering by saying things like, “Give me a couple of battera.” Eventually battera became the official name.

Before long, konoshiro hauls dropped and so it was replaced with saba. Also, in order to preserve moisture, sushi chefs started to wrap it in kelp sent by ship from Hokkaido. The shape now is a long, skinny rectangle and it no longer resembles a boat, but the name remains.


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Revision date: August 12, 2021

What is Masuzushi?

The origin of Masuzushi dates back about 300 years. Apparently, in 1717 it was first presented as Ayu narezushi (narezushi is a traditional food, said to be the original form of sushi and made from lactic fermentation of fish) to the third-generation feudal lord, Toshioki Maeda, by Shinpachi Yoshimura, a feudal retainer of Toyama who excelled in cooking skills. Toshioki liked the dish very much and assigned the role of vinegaring Ayu to Shinpachi. After that, it is said that the same narezushi was presented to the eighth shogun of the Tokugawa shogunate, Yoshimune Tokugawa, and that Yoshimune was extremely pleased with it.

Shinpachi’s ayuzushi was made through the painstaking process of washing salt-preserved ayu with sake, then pickling it for around 12 days, removing the rice the day before it was to be served, then adding new rice that had been flavored with sake and salt.

This transformed to the present-day Masuzushi in the late Edo period, when the amount of vinegar was increased. Hayazushi, in which vinegar is added to rice for a quick meal, became popular, and Sakuramasu started to be used instead of Ayu, These factors seem to have contributed to how it transformed into the Masuzushi we see today.

It is made by first filleting fresh Sakuramasu into three pieces and removing the skin and bones, then cutting into 3 mm thick strips. These strips are sprinkled with salt and left for 3 to 5 hours before being washed with a vinegar mixture made of salt, sugar and other seasonings (water is never used for this). The type and amount of seasonings mixed with the vinegar at this time is a secret and determines the house flavor of the restaurant or family. Sakuramasu that has marinated for 1 to 2 hours in the vinegar mixture is placed on sushi rice in the container, then held down with weights to press for several hours to complete the Masuzushi.

Long ago, it was only made with Sakuramasu caught in Jinzu River, so it was made between April and July. However, due to reasons such as a dam being built upstream and water pollution, Sakuramasu produced outside the prefecture and imported Masu (trout) is used now, and it is made year-round.


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Revision date: August 3, 2021

What is Funazushi?

Narezushi (mainly a preserved food in which fish undergoes lactic fermentation with salt and rice), in which Sushi finds its roots, can still be found even today throughout Japan. The most famous is Funazushi in Shiga prefecture.

Although it has “sushi” in the name, according to common knowledge of the day, it would be called crucian carp. The sweet and sour smell tickles your nose and it’s almost like pickled crucian carp. When you actually put it in your mouth it fills with an intense sourness and it can only be described as a really sour pickled food. However, the more you eat it, the more you somehow get used to it and in the end it becomes a favorite food that you will even crave. This effect is so mysterious that people even wonder, “Could this have been synchronized at some point with the tastes of our Japanese ancestors?”

Making Funazushi sushi is surprisingly simple. The only ingredients are crucian carp caught in Lake Biwa, rice and salt. First the internal organs are removed from the crucian carp, next it is salted and then it is shade-dried. This crucian carp is packed tightly into freshly steamed rice in a large cask. “Sushizume” refers to this precise situation, and the ingredients are packed in so there is no air inside. If air is let in, the oxygen will cause microbiota to grow. In other words, it will rot. This is the most important thing in making funazushi.

While this cask is left for eight months to two years, special microorganisms will cultivate even without oxygen. These are lactic bacteria and acetic bacteria, which work to change the entire contents into a sour flavor.

After that, the mushy rice is removed from the finished Funazushi, and only the crucian carp is consumed. However, let me reiterate, this sour flavor is intense and complicated. Comparing it to bleu cheese or camembert cheese might make it easier to understand. The taste is so intense that it makes some people sick.

Incidentally, there are records from when Hideyoshi Toyotomi advanced his army to the Korean peninsula (around 1592), that Funazushi from Oumi was presented to soldiers on the front line as a comfort food. This episode illustrates the fact that Funazushi was a dish of pride for the people of the town of Nagahama (where Toyotomi’s castle was located, now part of Shiga prefecture).


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Revision date: July 26, 2021

What is Black tiger shrimp?

Black Tiger is in the category of the largest shrimp that is part of the Kuruma Ebi family and grows to be up to 30 cm. Black Tiger gets its name from the fact that it looks black before it is heated and has stripes like a tiger. The official name in Japan is “Ushi Ebi” but the reason is unknown. The Black Tiger is cultivated heavily in places like China, Vietnam, Indonesia, Thailand and India. It started to be imported from Taiwan in the 1980s to compensate when Japan’s shrimp consumption could no longer be covered by Kuruma Ebi. At the peak, it accounted for 40% of Japan’s shrimp imports. There is a strong impression of shrimp being imported, but small Black Tiger can actually be caught in Japan from Tokyo Bay southward.

Black Tiger has a strong sweetness and firm meat but maintains its plumpness even when cooked with heat. It is known for the red color that appears when heated. The appearance and texture when eating Black Tiger is said to be similar to Kuruma Ebi, which is known to be a shrimp of luxury, so it is a very popular shrimp in Japan. It is used not only as a sushi topping, but in a wide variety of dishes, such as for deep-fried shrimp or Tempura.

For sushi restaurants, shrimp that has been boiled and had the head and shell removed is imported in vacuum-sealed bags. Once defrosted, it can be used as a sushi topping without any further preparations. At conveyor belt sushi restaurants it was even once presented as Kuruma Ebi.

One problem with Black Tiger, which is the mainstream farmed shrimp, is that it has little resistance to illness, and cannot be farmed in the same place continuously. Therefore, Black Tiger farming volume has dropped and currently Vannamei Ebi (Whiteleg shrimp) is becoming a major force in shrimp farming.


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Revision date: July 9, 2021

What is Shiromiru?

The official name of Mirugai is “Mirukui”. The part of the Mirugai that is used as a sushi topping is the siphon that bulges out from the shell. The siphon is separated from the shell and then this is cut through longways, from top to bottom. One Mirugai can only produce four pieces of sushi. It is also nearly extinct from overfishing. While it can still be caught in the Seto Inland Sea and Mikawa Bay, there are fishing limits, which means it is an ultra-high-priced sushi topping.

However, most conveyor belt sushi restaurants offer Mirugai at reasonable prices. The topping on these is quite white. In conclusion, this shellfish is actually Shiromiru (also known as Namigai or Japanese geoduck) and is mainly found in Aichi and Chiba. As the name suggests, the siphon is larger than Mirugai and whiter (“shiro” means “white” in Japanese). There is a certain flavor that is peculiar to shellfish that live in sandy terrain, which some people like and some people hate. However, at less than half the price of Mirugai, it makes a decent substitute.

Unfortunately, the number of Shiromiru is also declining. Now, in order to fulfill demand, Pacific geoduck is being imported from places like Canada and the U.S. and is also called Shiromiru at the Toyosu Market.


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Revision date: July 8, 2021

Sushiuniversity Hygiene Measures

Travelers’ health and safety have always been our priority and today, the focus on public health and hygiene is fundamental to the recovery of our industry.

For the purpose of allowing customers to enjoy SushiUniversity with peace of mind, we have implemented the following measures:

・Capacity management to avoid a crowded situation

・Physical distancing practices

・More frequent cleaning and regular deep cleaning

・Temperature check of staff and visitors

・Hand sanitizer or hand washing facilities are provided

・The staff has to wear a face mask throughout the activity


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Revision date: June 29, 2021

What is Yamawasabi?

Horseradish is believed to have originated in Eastern Europe. It’s a cruciferous vegetable, alongside mustard, wasabi, cabbage, and broccoli. Horseradish is very fertile, and buds and roots will sprout just by cutting the root stock part to an appropriate size and soaking it in water. Once transferred to soil the roots will multiply quickly even without any other efforts.

In Europe horseradish is used as an ingredient for sauces or to accompany sausage and roast beef, or as a subtle seasoning for other dishes. In Japan most is used as an ingredient in processed foods such as wasabi powder or wasabi paste. Unlike wasabi, horseradish is characterized by its pure white root and strong spicy flavor. In Hokkaido horseradish is called “Yamawasabi” and is a common sight at home dinner tables.

Farming of Yamawasabi for food started in the Meiji era and settled in Hokkaido. Currently over 90% of the domestic production in Japan is accounted for in Hokkaido. While it is grown throughout Hokkaido, the vast Yamawasabi fields befitting Hokkaido are especially prevalent in Abashiri and Kitami.

In Hokkaido, Yamawasabi is eaten as an accompaniment to white rice. Grated Yamawasabi is sprinkled on rice and there are also jars of “Soy sauce-marinated Yamawasabi” sold as a normal item at supermarkets. Besides on rice, it is also indispensable to Hokkaido cuisine as seasoning for hiyayakko (cold tofu) and sashimi.


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Revision date: June 28, 2021

What is Spot prawn?

One type of shrimp that is used for nigiri sushi when still raw is Botan ebi. Needless to say, it is an extremely new addition to the Edomae sushi topping list. Interestingly, there are two types of domestic shrimp that are called Botan ebi in the Toyosu Market.

One is called by its Japanese name, Toyama ebi, with a length of 25 cm, lives in the sea at depths of 100 to 400 m, and is normally caught in Funka Bay of Hokkaido on the Japan Sea side. It actually isn’t caught in Toyama very often despite being called Toyama ebi. At the cheapest it still costs US $20 per kilogram, and in rare cases can exceed $200 per kilogram. In the Toyosu Market, it is called “Torabotan” because of the tiger stripes on the shell (“Tora” is Japanese for tiger).

The other Botan ebi is the Humpback shrimp, which is found on the Pacific Ocean side at depths of 300 m or more and has a length of 20 cm. The main production sites are Suruga Bay, Chiba prefecture and Kagoshima prefecture. The catch is so unstable, and at one point it was almost non-existent, making this shrimp so rare that the Toyosu Market brokers have nearly forgotten about it. The price is even higher than Toyama ebi. In Toyosu, it is called “Honbotan”.

All Botan ebi look beautiful, have a pleasant texture and a mellow sweetness that goes perfectly with shari. Even at high-end sushi restaurants, there is no distinction between the two, and they are both served as Botan ebi.

Considering this, being served substitutes for Botan ebi is unavoidable. About 800 tons of the Spot prawn, found in the northern Pacific Ocean, is imported to Japan from the U.S. and Canada annually. The Spot prawn is a close relative of domestic Botan ebi and they can only be told apart by examining the head closely. It is sometimes called Ama ebi or Botan ebi in the U.S. and Canada. Furthermore, one does not taste better than the other. Especially when eaten raw, the sweetness is intense. The peak season is from April to October, and during this time it is imported live, fresh and frozen.

In the Toyosu Market, it is called Spot ebi and separated from Botan ebi, but is used as Botan ebi in various restaurants and inns. The price is a little lower than the domestically produced but is definitely still an expensive shrimp.


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Revision date: October 5, 2021

What is Rendaku?

In Japanese, when a compound word is made out of two individual words, and the first consonant of the second word changes from a “clear sound” to a “fuzzy sound”, it is called “Rendaku”. For example, Edomae (江戸前) + sushi (寿司) changes to Edomaezushi (江戸前寿司). However, the correct pronunciation is only generalized among Japanese people, so in this book we chose the most commonly searched version of each compound word.

Examples of Rendaku:

Nigiri (握り) + sushi (寿司)→Nigirizushi (握り寿司)

Inari (稲荷) + sushi (寿司)→Inarizushi (稲荷寿司)

Masu (鱒) + sushi (寿司)→Masuzushi (鱒寿司)

Kaiten (回転) + sushi (寿司)→Kaitenzushi (回転寿司)

Kuro (黒) + tai (鯛)→Kurodai (黒鯛)

Ma (真) + tako (蛸)→Madako (真蛸)

Aka (赤) + kai (貝)→Akagai (赤貝)

Tori (鳥) + kai (貝)→Torigai (鳥貝)

Shiromi (白身) + sakana (魚)→Shiromizakana (白身魚)


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Revision date: June 9, 2021

What is shirakawa?

Out of the five types of Amadai that live in Japan, Aka-amadai, Shiro-amadai and Ki-amadai are the three types offered in the markets.

The main characteristics of Aka-amadai are its overall red body, the bright yellow color under the eyes and how part of its fin is a shiny cobalt blue color. Aka-amadai is called “Guji” in the Kansai region and is a vital part of Kyoto cuisine. Ki-amadai has the same silhouette and size as Aka-amadai, but the Ki-amadai has more yellow color in its face and tail fin. They tend to prefer sandy seafloors at depths of 30 to 300 m and live deeper than any other type of Amadai. True to its name, Shiro-amadai is a white color (Shiro means ‘white’) so is also called Shirakawa (which means ‘white skin’).

Shirakawa is considered to be the finest of the Amadai and can cost more than US $100 per kilogram. Aka-amadai costs around US $40 per kilogram. Shirakawa always ranks in the top three fish for market price. Shirakawa has more elasticity than the other two and has rich fat, making it perfect as sashimi or a sushi topping. The umami is so strong that even when served raw, the customer sometimes thinks it’s been prepared using kobujime. The fat between the meat and the skin is sweet and the skin is delicious in its own right, so it can even be eaten as sashimi with the skin left on. The famous production sites include Tsushima in Nagasaki Prefecture and Yawatahama in Ehime Prefecture. They are in season from autumn to winter. However, they say in a catch of 1,000 Amadai, you can only get one Shirakawa, so it is a rare item you won’t often see, even in a high-end sushi restaurant.


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Revision date: October 5, 2021

What is Shiojime?

When preparing fish, it is sprinkled with salt 30 minutes to one hour before cooking. Sushi chefs also salt fish for almost the same purpose. This is called Shiojime. Shiojime brings out excess moisture and fish odor from the fish. At the same time, the proteins that make up the fish’s muscles dissolve, giving it tenacity. The result is that the fish meat gets resiliency. Another objective is to eliminate the bacteria on the surface of the fish. In sushi preparations, Shiojime is often followed by Sujime. The amount of vinegar that permeates the fish depends on the circumstances of Shiojime, so it is an extremely delicate task.


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Revision date: May 14, 2021

What is Karami?

Sashimi essentials such as wasabi, ginger, karami-daikon, etc., are collectively called “Karami”. Originally Karami was a type of Tsuma. From the mid to late Edo period, Karashi (mustard) was mainly used for karami in sashimi. Eventually, due to the influence of Edomae sushi, wasabi became the norm. For sashimi such as bonito and sardines, wasabi isn’t enough to offset the peculiar aroma. In some cases, it is better to use ginger, which works on the root components of the odor. These types of fish have the best flavor once spring has passed, and interestingly enough, wasabi is least prevalent in summertime, while ginger is in peak season. Mother nature seems to know what she’s doing.


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Revision date: April 5, 2021