Savor the Taste of Japan’s Seas Through These 5 Types of Shellfish

  • FOOD
  • As Japan is an island country, it is blessed with a wide variety of seafood which can be harvested from the seas surrounding the country or obtained at rearing farms. However, do you find yourself at a loss when faced with a mind-boggling range of shellfish? As most of their names are written in Hiragana and Katakana on menus and that many menus in Japan do not feature photos of their dishes or ingredients, it can be a bit intimidating at first for anyone to order shellfish especially if they don’t know Japanese. Fret not, here is a guide on 5 types of commonly seen shellfish in Japan so the next time you visit a seafood or sushi restaurant during your trip, or buy these shellfish and bring them home, you will know what you are getting and how to enjoy them in the best way!

    Various shellfish

    1. Asari (あさり / アサリ)
    Asari no sakamushi

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    sawaさん(@sa7.survive)がシェアした投稿 –

    Asari i.e. Manila clams or Japanese littleneck clams are such a common sight in Japan that you can find them in a variety of dishes such as miso soup and asari no sakamushi (あさりの酒蒸し) i.e. Manila clams steamed in Japanese sake. The asari is most often seen at 10 meters below sea level in tidal zones of inland seas and can be obtained in bulk during the clam-digging season at low tides. It is said that the asari found in clearer waters tend to be more delicious than those found at sandy areas or murky waters. If you look at the patterns on the surface of the shells covering the clams, they are unlikely to be the same so many types of designs can be observed. In order to clean the asari, it is recommended to soak them in salt water and leave them overnight so that they would “spit” out the sand naturally which can then be easily washed away.

    Although the asari is available all year round in Japan, the most delicious ones are said to be harvested in spring (March to May) and autumn (September to October). This has to do with the clam-digging season in spring between mid-March and April, as well as the asari’s spawning season which is typically between May and December.

    Up to the 1980s, most of the asari found in Japan were produced domestically. However, due to overfishing and land reclamation projects which affected the asari’s natural habitat, the amount of asari harvested within Japan has been affected. In recent years, a lot of the asari found in Japan are imported from China and South Korea, while those produced domestically are usually reared in farms rather than naturally harvested. The no. 1 prefecture that produces the most asari is Aichi Prefecture which accounts for close to 60 percent of the national output followed by Shizuoka and Mie. If you happen to be in these prefectures, you should give their local asari dishes a try.

    The asari is extremely rich in iron and vitamin B12 so it is highly recommended for people who are anemic or have low blood pressure and pregnant women. In order to boost the iron content in the asari, it’s best to cook them in the tsukudani style i.e. boiled down in soy sauce which is said to increase the iron level by three times than when the asari is raw. The asari is also highly regarded for its taurine content which is useful in preventing arteriosclerosis by reducing excess cholesterol build-up and improving your liver function.

    2. Awabi (あわび)
    Raw awabi

    The awabi i.e. abalone is a type of shellfish which is active at night and hides in rocks and sand during the day. It is said that there are about 100 species of the awabi in the world but only 10 can be found in Japan. Of these, the four edible types which are considered more popular and common are the kuro awabi (黒あわび) i.e. black abalone, megai awabi (めがいあわび) i.e. disk abalone, ezo awabi (えぞあわび) i.e. ezo abalone, and madaka awabi (まだかあわび) i.e. giant abalone. The kuro awabi is regarded to be of top quality and naturally is the most expensive.

    When selecting awabi, it is said that those that are heavy and have thin shells are best. If you want to store live awabi in the chiller section of the fridge, note that they can be kept for 2 to 3 days during summer and 3 to 4 days during winter. Simply wrap the awabi in newspapers which have been soaked in salt water and place the awabi with the shells facing downwards into a bowl. However, do not cover the top of the bowl or put cling wrap over it. On the other hand, if they are to be stored in the frozen compartment of the fridge, the awabi’s body, liver, and base should be separated and placed into airtight bags. Upon thawing, they should not be eaten raw but should be heated or cooked thoroughly before eating.

    Grilled awabi and awabi sashimi

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    Keiーkei-jiroさん(@kei_kei_jiro)がシェアした投稿 –

    In Japan, the places where the most awabi is harvested are the Boso Peninsula in Chiba Prefecture, the Izu Peninsula, and Ise-Shima. Depending on the type of awabi and where it was harvested, the prime season to eat awabi differs. Generally, the prime season is before the spawning period. For kuro awabi, the best time to eat it is during summer; while for the megai awabi, those harvested in Minamikyushu during winter are considered to be the most delicious. There are a variety of ways to eat the awabi where the most common ones are by grilling them with the shells or in the form of awabi sashimi.

    The awabi is regarded as a treasure box of nutrients as it contains a lot of protein, collagen, zinc, iron, copper, magnesium, chondroitin, taurine, potassium, and vitamins A and B. On the other hand, it is said that the awabi has low levels of fat, cholesterol, and calories. As such, the awabi is regarded especially good for pregnant ladies and their babies in the formation of their retinas and eyes, prevention of flu, and beauty effects.

    3. Kaki (カキ / 牡蠣)
    Raw oysters

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    M MAGAZINEさん(@mmagazine_kyoto)がシェアした投稿 –

    The kaki i.e. oysters are a common sight in Japan and are served in a variety of ways such as in its raw form with lemon juice, deep fried as kaki fry, grilled on its own or with miso and herbs, and in stews or hot pots. It is a favorite among many people for its springy texture and rich taste. Although there are as many as 25 types of kaki that can be found in Japan, the two main categories of kaki sold in Japan are the magaki (真牡蠣) i.e. Pacific oysters which are usually reared in farms and more widely distributed, and the iwagaki (岩牡蠣) i.e. Japanese oysters which are limited in quantity, harvested naturally, and more expensive. The magaki is in season during winter from November to March, while the iwagaki is best enjoyed during summer from June to July. As the magaki’s spawning season is in summer, it is generally too small to be enjoyed. Coupled with the hot weather which leads to the increased activity of bacteria that causes food poisoning, it is said that the magaki is best enjoyed up until the hanami (flower viewing) season in March.

    Although there are many places in Japan where the magaki is reared, here are four of the more well-known locations where you can get the best magaki:

    1. Itsukushima in Hiroshima Prefecture
      Hiroshima has the largest catch of magaki in the country whereby the currents in the Seto Inland Sea are said to make the flesh of the kaki firm and delicious.
    2. The Sanriku region in Miyagi Prefecture
      The ria-style coastline of the Sanriku region is said to be one of the top three fishing grounds in the world and the magaki reared here are low in fat and high in iron.
    3. Matoya in Mie Prefecture
      The Matoya oysters are especially famous and popular due to the fact that they can be ready for harvest in just a year as compared to other prefectures which need at least two to three years. It also has a strong sweetness and is less bitter than its peers.
    4. Lake Saroma in Hokkaido Prefecture
      This is the most northern kaki rearing spot in Japan where the cold sea waters of the Okhotsk Sea and the freshwater from Hokkaido’s land come together to produce a bountiful supply of plankton which serves as nutrition for the kaki.
    Various kaki dishes

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    匿名希望さん(@makoto_forest)がシェアした投稿 –

    To select the freshest and most delicious kaki, there are some pointers depending on whether it comes with its shells or not. For the oysters that are yet to be opened, the shells should be firmly closed or should close once they are touched. Heavier ones are preferred and there should not be any foul smell. For the oysters which have already been removed from their shells, they should be milky white, plump, springy, and have a shine. The mantle should be in a dark color as close to black as possible, while the adductor muscle should be translucent and not detached from the body of the kaki.

    To prepare kaki, the first thing to do is to put them into a bowl along with salt and potato starch before mixing them well. The salt removes the sliminess while the potato starch takes away the dirt. Once this has been done, add water and mix gently. Pour away the dirty water and wash the kaki quickly for another two to three times so as to prevent the loss of its nutrients.

    As freshness is of essence to the kaki’s taste, it is recommended to eat them quickly upon purchase but if you happen to have leftovers, there are ways to preserve the freshness of the kaki. For those that are still shelled, they should be wrapped up in wet newspaper which had been soaked in salt water before being placed in the refrigerator for a maximum of three days. However, if the shell of the kaki is not completely closed, it is a sign that the kaki is no longer living so it should not be consumed. As for the unshelled kaki, they should be kept in the refrigerator while soaked in the pasteurized seawater provided upon purchase. You should try to consume them by the following day at the latest or else it is best to store them in the freezer. For frozen kaki, it is highly recommended that they should be fully cooked before consumption so one of the more popular ways is to make kaki fry.

    The kaki which has a nickname of “the milk of the sea” is surprisingly low in calories and has lots of nutrients. For example, the glycogen allows a more effective conversion of sugar in the kaki to energy by as much as 50 percent and is said to be of help in boosting the liver’s function and reducing fatigue. For those who are anemic, the kaki’s high content of iron, copper, and zinc are effective in preventing the condition. In fact, you can get more zinc from the kaki than in milk and spinach which is important for the production of enzymes in the body. As for taurine, it helps to boost the absorption of fats and prevent the rise of cholesterol in blood. Last but not least, amino acids such as methionine and cystine are believed to improve one’s complexion and smoothen skin so ladies should give this a try!

    4. Hamaguri (はまぐり / ハマグリ)
    Grilled hamaguri

    The hamaguri i.e. common orient clam or hard clam is another common shellfish found at many seafood restaurants in Japan whereby one of the most popular ways of eating it is straight from the grill. The most interesting thing about this method of cooking is that the hamaguri pops open with a loud sound once it’s cooked. Upon seeing this, it’s time for you to pour in condiments such as soy sauce into the opened hamaguri and watch its natural juices sizzle with the heat. Beware of scalding yourself, though, and allow the hamaguri to cool slightly if you are eating directly from the shell. You will surely find the fresh ocean flavor from the hamaguri hard to resist once you have sampled it!

    Hamaguri shabu-shabu

    Other than this method, the hamaguri can also be found in dishes such as clam chowder, hot pots, dobin mushi, kushiyaki, sushi, or boiled in sake. Due to the presence of thiaminase in the hamaguri which breaks down vitamin B1, the hamaguri is never eaten raw.

    In the past, the hamaguri could be harvested from places south of the Tohoku region. However, the numbers dropped drastically from the late Showa era due to land reclamation and embankment works which destroyed the shallow waters where the hamaguri resided at. As such, other than the west part of the Seto Inland Sea and parts of the Ariake Sea, there are a few natural habitats for the hamaguri in Japan. Most of the hamaguri harvested in Japan come from Kumamoto Prefecture but volumes are low as compared to the imported shina-hamaguri (シナハマグリ). As for those from Chiba Prefecture, they are largely from the deep seas and are called chousen-hamaguri (チョウセンハマグリ). Apparently, this situation concerning the hamaguri is so dire that in 2012, it was classified as an endangered species in the Ministry of the Environment’s Red Data Book.

    The hamaguri is a popular food item especially during the Hina Matsuri (Doll Festival) in March due to its two shells which signify the wish for girls to find a perfect match in marriage. As such, demand for this shellfish is very high during this period.

    Coincidentally, the best season to eat hamaguri is between February and April i.e. from winter to early spring. In Japan, the Kashima Sea in Ibaraki Prefecture accounts for 70 percent of the domestic hamaguri harvested, while the remaining percentage comes mainly from Ise Bay, Suo Sea, and Ariake Sea. However, due to the small amounts, the price of these hamaguri is so high that they are usually not sold in retailers like supermarkets. As such, if you do find hamaguri being sold in retail outlets, chances are those are the cheaper shina-hamaguri imported from China.

    As for how to choose the freshest hamaguri, look out for those whose shells are firmly closed and have a bright sheen on its surface. The shells can also be an indicator of the hamaguri’s age since those which are younger tend to have clearer patterns on the shells. If you are buying the hamaguri which are not pre-packed, try knocking the shells together and select those which have a crisp sound like metals banging together.

    Just like the asari, the hamaguri needs to be washed thoroughly in order to remove the sand within. Simply prepare a salt water solution and soak the hamaguri in it. If you are in a hurry, you can soak the hamaguri for just 2 hours but ideally, it should be left in a cool and dark place overnight such as in the fridge.

    The hamaguri is especially rich in calcium and magnesium which are essential nutrients for the body in strengthening bones and prevention of anemia. In addition, the taurine in the hamaguri is said to reduce the accumulation of lactic acid, remove fatigue, lower blood viscosity, and cholesterol. Last but not least, the vitamin B12 in the hamaguri which can’t be obtained through vegetables will be useful in the synthesis of DNA and in the proper functioning of nerves.

    5. Hotategai (帆立貝 / ホタテ貝)
    Live hotategai

    The hotategai i.e. Japanese scallop is a delicate shellfish which cannot grow in waters that are too hot or too cold so the perfect temperature is somewhere between 5 to 19 degrees Celsius. Most of the hotategai available in Japan are reared in Hokkaido and Aomori and it takes at least three to four years for the shellfish to grow up to a size of at least 12 cm wide. Since there is a steady supply of reared hotategai in the market, it is available all year round. However, the best season to eat the hotategai is in January i.e. winter which is also its spawning season. As for the naturally harvested hotategai, they tend to come from the Okhotsk Sea and east of Hokkaido. Even though the methods differ, the reared and naturally harvested hotategai actually taste similar since the reared ones are merely protected from its natural enemies and there are no artificial feeds given to them.

    The hotategai can be eaten in various ways and processed into other forms. Besides the most common ways of grilling in butter and boiling it, it can also be eaten as sashimi, a topping on sushi, and in soups and stews. In order to pick the freshest hotategai, look out for those whose shells are tightly closed. If you are selecting the shelled versions, get those where the adductor muscle is plump, fleshy, and has a nice sheen on its surface. You would also notice that the gonad surrounding the adductor comes in two colors: it will be white for males and reddish-orange for females.

    Preparing the hotategai is relatively easier since you only need to wash it lightly with water after removing the adductor muscle from the shells and gill. The adductor muscle can be stored in the freezer and naturally thawed in the chiller section before cooking.

    Dried scallops

    Besides the raw and boiled hotategai which are widely available in chilled and frozen form, the adductor muscle can also be dried to become the hoshi-kaibashira (干し貝柱 – dried scallops). In Japan, this is usually eaten together with alcoholic drinks, but in Chinese cuisine, the dried hotategai is a priced ingredient which is added to soups, stews, and even fried rice for a rich seafood flavor. Another usage for this food item is the XO sauce which is actually a mixture of high-quality oyster sauce and the dried hotategai.


    The hotategai is said to contain high amounts of taurine and vitamin B12 which is good for relieving fatigue and preventing anemia. Other than these, it contains folic acid, zinc, and iron that contribute to the wellness of the body in their own ways. Last but not least, the hotategai is believed to be a low-calorie food with 72 calories per 100 grams.

    Now that you’ve read about these different types of shellfish, are you more confident about ordering the right thing the next time you visit a seafood or sushi restaurant? Have fun exploring these flavors and savor the freshest seafood while you are in Japan!

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