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What is the difference between rock oysters and true oysters? ? The Young Oyster Association will explain.

There are two types of oysters in Japan: true oysters and rock oysters. Both are said to be delicious, but what is the difference?

This time, we will introduce the differences between true oysters and rock oysters, and recommended oysters for each!

If you read this blog, you will understand the differences and will find oysters more interesting, so please read until the end.

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True oysters are in season in winter

True oysters are mainly produced in Hokkaido, Miyagi prefectures, and Hiroshima prefectures, but they can also be harvested all over the country, including Ishikawa prefecture and Fukuoka prefecture.

The season for true oysters is winter. It is harvested from October to April . True oysters have the characteristic of spawning in large quantities all at once, so from around spring onwards there will be no meat available. (Triploid true oysters are an exception)
Therefore , true oysters are considered to be in season during the winter before spawning .

The representative true oysters, the exquisite oysters from Higashimatsushima, Miyagi Prefecture, have the highest repeat rate, and are so popular that some people eat them every week during the season!

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Goto Suisan's Naruse Oysters Young Oyster Association Goto Suisan

However, there is now a type of oyster called triploid true oyster that becomes crispy from summer to fall, and can be enjoyed almost all year round.

Click here for the triploid true oyster whirlpool champion

True oysters range from those with a light and bland taste to those with a sweet and creamy taste with concentrated umami. It is loved by many people because it has a soft and pleasant texture.

True oysters are sometimes used in dishes such as fried oysters and oyster gratin, and one of their appeals is that they can be eaten in a variety of ways.

We have started the hometown tax payment for the whirlpool champion, so we recommend you to donate your hometown tax!

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Rock oysters are in season in summer

Iwa oysters are large oysters that are mainly cultivated in the waters of Yamaguchi, Shimane, and Tottori prefectures. Now they are also farmed in Tokushima and Fukuoka prefectures.

The season for rock oysters is summer, from May to September . Rock oysters spawn slowly over a period of several months, so they remain firm and delicious even in summer.

Also, because rock oysters take time to grow, their shells and flesh can grow very large . They are characterized by being larger and thicker than true oysters.

Despite their large size, rock oysters have a delicate and meaty taste .

Rock oysters are also the most delicious oysters when eaten raw.

The photo below shows creamy oysters from Kinmorimaru Suisan.

Click here for oysters from Kinmorimaru Suisan

Difference between real oysters and rock oysters

As mentioned above, the major difference between true oysters and rock oysters is that they are in season. True oysters are in season from October to April, and rock oysters are in season from May to September .

It's also about taste and texture. True oysters have a light flavor and a soft texture, while rock oysters have a rich, full-bodied flavor and a firm texture.

As a side note, oysters are rich in protein, vitamin B12, iron, zinc, etc., and are said to be effective for boosting immunity, recovering from fatigue, and beautifying your skin . Both true oysters and rock oysters share this point.

Recommended true oysters and rock oysters that can be eaten raw

true oysters

If you are unsure, this is it! True oysters have the highest repeat rate

"Goto Suisan's Naruse Oyster" in Higashimatsushima, Miyagi Prefecture

This is the oyster with the highest repeat rate. It can be eaten raw, but it comes shelled, so you don't have to peel it yourself.

Buy Naruse Oysters from Goto Suisan now

“Uchi no Umi Oysters” are winter true oysters made by fishermen who farm whirlpool champions in Naruto City, Tokushima Prefecture.

The 2024 oysters are bite-sized and easy to eat, and are delicious whether raw or steamed.
These oysters are affordable and recommended for those trying shell-on oysters for the first time!

Click here for my sea oysters

Fukuoka prefecture brand oysters “Itoshima oysters”

These are true oysters that can be eaten raw with their shells on and are the most popular on the Oyster Young People's Association online shopping site.

Click here for Itoshima oysters

Tokushima prefecture brand oyster “Uzushio Champion”

Uzushio Champion is a Tokushima brand oyster that is in season from September to December, which is rare for real oysters.

True oysters are very popular among people who like big oysters.

Click here for Whirlpool Champion

rock oysters

Fukuoka prefecture brand oyster “Aya”

Although it is on the small side for rock oysters, it is a very popular rock oyster with a very refreshing taste and creamy taste.

Click here for Aya

Tokushima prefecture brand oyster “Uzushio King”

"Uzushio King" is a rock oyster made by the same producer as "Uzushio Champion." They are large oysters, and are recommended for those looking for size.

Click here for Uzushio King

Kagoshima prefecture brand oysters “Nishikimorimaru Tenkai”

"Nishikimorimaru Tenkai" is a super creamy rock oyster representing Kagoshima Prefecture. It was the most delicious rock oyster I've ever eaten. Rock oysters are often referred to as. Recommended for those who like big, creamy oysters.

Click here for Nishikimorimaru Tenkai


True oysters and rock oysters differ in season, taste, texture, and production area. True oysters have a light taste and soft texture, and are said to have a rich flavor and richness when eaten in winter. On the other hand, rock oysters have a rich, rich flavor and a firm texture, and are said to be most delicious when eaten in the summer.

If you are interested in food culture and cooking, it would be a good idea to compare true oysters and rock oysters and choose the one that suits you best. It is also important to enjoy oysters in moderation, paying attention to their nutritional value and health benefits, and considering a balanced diet.

However, there is a risk of food poisoning when eating raw oysters, so care must be taken to prepare them properly and maintain hygiene. Recently, oysters such as true oysters and rock oysters have become popular all over the world. In Japan, oyster festivals and oyster specialty restaurants are increasing in number.

In addition to eating oysters, they can also have positive effects on your body. Vitamin B12 is known to improve brain function. Oysters are rich in both, and are said to be effective for beauty and diet.

Finally, true oysters and rock oysters are delicious ingredients with their own unique charms. Both are nutritious and good for your health, so we recommend consuming them in moderation. There are many different ways to eat and prepare oysters, so find your favorite way to enjoy oysters.

The Young Oyster Association not only sells raw oysters, but also extremely delicious oysters pickled in oil and oyster pizza.

We have a lot of delicious products lined up, so please take a look.

Young Oyster Association Mail Order Site

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