What is Ciguatera fish poisoning?

a photo of Star snapper

Ciguatera fish poisoning is a type of food poisoning caused by consuming certain fish that live in tropical and subtropical coral reef areas such as Moray eel, Grouper, Star snapper, Japanese scavenger and Parrot fish.

It is caused by toxins such as ciguatoxin, but it mainly generates from dinophyceae that are stuck to algae. The process of ciguatera occurring involves the food chain. Even if a fish itself doesn’t originally contain toxins, an herbivorous fish may eat algae that turns it toxic. That fish may be eaten by a carnivorous fish, which then accumulates high concentrations of ciguatera in its body. When a human consumes the carnivorous fish it can cause food poisoning in the human. There are as many as 300 species of fish that contain ciguatoxin. The ciguatoxin, which causes the food poisoning, cannot be killed by boiling or grilling, so it can’t be prevented through food preparation.

Symptoms of this food poisoning mainly consist of sensory nerve abnormalities, muscle soreness, itchiness and abdominal pain, but it is rarely fatal. However, it takes quite a long time to recover from compared to other toxins and the average recovery time is said to be two to three weeks. It is vital to diagnose ciguatera fish poisoning as soon as possible. Most symptoms develop within one or two hours and up to to 24 hours after consumption and one unique symptom is dysthermesthesia. This is a form of dysesthesia in which touching cold things feels like its burning. It occurs one to two days after the poisoning and is a known characteristic of ciguatera fish poisoning. Another characteristic symptom of ciguaterafish fish poisoning is joint pain within 24 hours after consuming the fish. In any case, it is important to be seen by a specialist as soon as possible.

Incidentally, the name ciguatera came from Spanish immigrants to Cuba as a name for food poisoning caused by the cigua shellfish in that region. Later it was also used to describe fish poisoning, which causes similar symptoms.


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Revision date: May 9, 2022

What is Yake or Yake-maguro?

An illustration of Longline fishingTuna fishing methods include Purse seine fishing, Fixed-net fishing, Drift-net fishing and Longline fishing, among others. Ocean fishing for tuna in the South Pacific Ocean, Indian Ocean and Atlantic Ocean, is often done by longline fishing. A main line can exceed 150 km in length and have over 3,000 hooks hanging from it. A main line is let out for 6 to 7 hours, and it takes 3 to 4 hours from running the line in the sea, to catching tuna. After that it takes another 10 to 15 hours to reel it up, so the tuna that was caught early may have already died during this time. There are times when sea water may feel warm to the touch, even in the dead of winter. The problem here is, that the body of the tuna that died early, will be warmer if the sea water is warmer. The body temperature will also be unusually high if a tuna caught by a hook ends up struggles for a long time and dying before being reeled in. The same is true for Kuromaguro caught in game fishing.

When this tuna is cut into pieces, the meat is whitish, as if grilled in a fire, so it is called “Yake (焼け)” or “Yake-maguro (焼け鮪)” as “Yake” means “burnt” in this case. The meat can also be a grayish-brown. In the industry it’s known as “White tuna” due to its color. It loses its characteristic red color, the texture of the meat when eating it is flakey and it doesn’t taste good.

Even if the fish body is cooled with ice water after catching, once the meat has been “burnt”, it won’t turn back to red. This renders even the premium Pacific bluefin tuna and southern bluefin tuna worthless, with zero commercial value as food. However, the fishermen don’t just toss the dead fish back into the sea without a second thought. This is mostly processed into pet food. Also, since it can’t be determined externally whether the meat is “burnt” or not, no one can tell until the fish has been cut open. It runs a big risk to the broker and can be a cause of its fishing port brand losing credibility.

It is currently believed that burnt tuna occurs from high temperature and low pH in the muscles of the fish after death, and that there is a complicated, indirect causal relationship between the conditions such as the environmental temperature, fishing method, handling of the catch, length of processing time, type of fish and size of fish. However, the mechanism that causes this phenomenon is not clearly understood.


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Revision date: March 1, 2022

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

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

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

What is Toro Katsuo (Torogatsuo)?

Toro is an absolute at sushi restaurants and it’s only natural to aspire to such a position. That’s why there are so many sushi dish names that start with “Toro”. The most laissez-faire of these is Toro salmon. In this case the definition of Toro is ignored in an attempt to promote sales. Just as bad is Toro katsuo (pronounced “Toro-gatsuo” in Japanese).

Katsuo is born in the warm southern seas. When it reaches about two years old it migrates north in pursuit of Iwashi and other small fish. There are two routes taken by the Katsuo that come to the seas around Japan. One of the routes rides the Kuroshio Current (a warm current) from around the Philippines, passing by Taiwan and the Ryukyus Islands, arriving in southern Kyushu. From there the Katsuo rarely heads toward the Sea of Japan and instead the majority moves northward on the Pacific Ocean side. The Katsuo migration schedule may shift depending on the temperature of the seawater and how the schools of Iwashi and Aji (which the Katsuo feeds on) are migrating that year. The first group appears around Ishigaki Island about January, then in the seas off the shores of Kyushu and Shikoku between February and March. It then moves to the seas off of the Izu and Boso peninsulas between April and June. It reaches the open seas off the southern coast of Sanriku and Hokkaido between July and September.

Another route follows the Ogasawara ocean current from below the equator in the seas off the shore of Papua New Guinea and the seas around Micronesia to the Ogasawara Islands, along the Seven Islands of Izu and approaching the open seas off the Boso Peninsula. The route then goes northward to join with the routes mentioned above.

It’s the Modori-gatsuo that begins reverse migration toward the south at the beginning of autumn when the water temperatures start to drop. Katsuo has a strong appetite before returning south in preparation for the long trip. Unlike the light-flavored Hatsu-gatsuo, the Modori-gatsuo has plenty of fat and its body fattens up quite a bit. The main fishing locations for Modori-gatsuo are in the northern Pacific, such as the waters off the shore of Sanriku. This is the season when it is truly worthy of the name Toro katsuo when served raw, and nothing else should be called by the same name.


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Revision date: December 1, 2021

What is Warisu?

Warisu refers to the vinegar when doing Sujime.

The fish is first washed in water, then soaked in vinegar. When working with blue-backed fish, the smell of the fish’s fat is removed from the surface with vinegar that has been used once before (and thus has a low acidity). This is called Suarai. When preparing fish with Sujime, cooled Warisu is used, made either with a 10 to 3 ratio of vinegar to ice, or the same ratio of vinegar to cold water. Vinegar with a high acidity that hasn’t been cut with water only soaks the surface of the fish (denaturing it) and the vinegar does not penetrate to the inside. In addition, if the temperature of vinegar is high, such as during summer, the skin and body of the fish soften. That’s why the vinegar is diluted (acidity is between ph 3.3 and ph 3.7) and used as chilled Warisu. After the Sujime of the topping is finished, it is important to place it in the refrigerator and allow the meat to mature slowly. For fish with strong fat, that fat oxidizes faster than the meat can mature, so it must be done very carefully.


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Revision date: November 23, 2021

What is Sekisaba?

Sekisaba (関サバ) and Sekiaji (関アジ) are ‘designer’ fish known for their high prices.

Of them, Sekisaba is a premium fish that can go for as high as US $50 per fish. So, what kind of fish is Sekisaba and what’s the difference between it and normal Saba (Mackerel)?

Sekisaba is a Saba caught in the Hoyo Strait with a fishing pole by a union member of the Saganoseki branch of the Oita National Federation of Fisheries Cooperative (JF Oita). In other words, Sekisaba is not a type of Saba, but a premium fish created by differentiating the fishing method.

Sekisaba started to become known all over Japan between the late 1980s and early 1990s. Until then, Sekisaba was only known as a commonplace fish that was caught incidentally with Aji and went for US $2 per fish.

However, the Saganoseki branch of JF Oita applied for the first trademark ever in the industry and then grew the brand through methods such as tagging each individual fish by hand. This resulted in recognition of its taste as “Saba that can be enjoyed even as sashimi” (while Saba is generally a fish that loses its freshness easily and not eaten raw), catapulting it to a national constituency  After that, the thorough quality management and branding paid off and the price jumped to 10 times that of normal Saba.

The first difference between Sekisaba and normal Saba is that Sekisaba is caught carefully, one at a time. The use of ground bait is also banned so that the Sekisaba won’t eat anything but the natural diet (avoiding odor). Each fisher is only allowed to use fishing lures they make from fish skin or ragworms. Fish caught in this way are let out into a live holding tank on the ship and brought to the fishing port alive. After arriving at the port, the tank on the ship is checked, the fish size is looked at from the water surface and the approximate weight is measured. This method is called “Tsurugai”. This is because when the fish is placed on a scale, it struggles violently and can injure itself. The fish are allowed to calm down in the tank for a day at the fishing port. At the time of shipping, Ikejime is performed, in which a knife is put into gill parts, the spinal cord is cut, and then it is submerged into saltwater and the blood is let out. After that a processing method called Shinkeijime is performed in which a wire is inserted into the spinal cord to put the fish in a state of asphyxiation. Therefore, there is little damage to the fish, maintaining the freshness.

The Hoyo Strait where Sekisaba is caught is rich in plankton, which the Sekisaba feeds on, and the flow of the tide is fast. The reason Sekisaba meat firms well and is fatty year-round is thanks to the good environment of the sea it is raised in.

If you come across a Sekisaba that so much work has been put into, try it as sashimi, not Nigiri sushi. This is because Saba, which has a peculiarity to it, is unpopular among some people. However, Sekisaba doesn’t have this off-taste and doesn’t taste like Mackerel, so even people who don’t care for fish should be able to find it tasty.


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Revision date: October 25, 2021

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 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 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 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 (連濁):

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 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

What is the trick to super cheap Ikura at conveyor belt sushi restaurants?

Immature salmon eggs still wrapped in ovarian membrane and salted are called sujiko. Ikura is salmon roe in which each mature egg is separated from the ovarian membrane before laying the eggs and then salted or marinated in soy sauce. The ikura of Chum salmon going upstream in the Kushiro River and Tokachi River in Hokkaido From October to December are considered to be premium ikura.

For cheap ikura, roe broken up inside the ovarian membrane in a fish that is approaching spawning time called “barako” is used. When the ovarian membrane of barako is torn, the eggs will fall out and scatter, so while they don’t take much work to prepare for serving, they also don’t taste particularly good. Even cats turn up their noses at barako, so they are also called “neko-matagi”, which literally means “the cat walks over it” and is used to refer to unpalatable fish. However, each egg is large and they look very appealing, so they are used at higher-end conveyor belt sushi. Unlike the 100-yen (US $1) restaurants, these higher-end restaurants don’t use disguised fish or substitute fish. This is because their basic business strategy is to differentiate themselves by attracting customers with authentic toppings. Generally they market the high quality of their toppings, but the ikura is actually this cheap “neko-matagi”.

Beneath this strategy of attracting customers with authentic toppings is this “Deceptive business strategy”. Salmon also swims upstream in the rivers of Tohoku and Hokuriku. However, the taste of ikura tastes inferior to that in Hokkaido. This ikura is also served at the higher end restaurants. That’s because although it doesn’t taste as good, it’s orthodox ikura. In case of orthodox ikura, the roe is used within one hour of the catch. But, if time passes and the freshness drops, the eggs will dry out and the surfaces will dimple, wrinkling. This is the type of ikura that is cheaper and often served at the cheap conveyor belt sushi restaurants.

The most commonly used roe in conveyor belt sushi restaurants is ikura from cheap Alaskan or Russian Chum salmon. An even cheaper type is masuko. Besides the masu roe, raw materials included soy sauce, salt, fermented seasoning, amino acids, reduced sugar syrup, enzymes, fish sauce, and fish and shellfish extract. For homemade versions, only soy sauce, mirin (sweet cooking sake) and sake are used.


We hope this information will be helpful.

Revision date: March 9, 2021