A Beginner’s Guide to Japanese Seaweed

By Ashley Owen
Updated: November 4, 2022

Seaweed is an integral component of Japanese cuisine. It’s a versatile and flavorsome ingredient that’s used in all sorts of dishes, including high-end sushi, hearty ramen broth, on-the-go snacks, and summery salads. Thanks to its high levels of key nutrients, Japanese seaweed is also greatly valued for its wealth of health benefits. 

There are actually many different types of seaweed used in Japanese food, ranging from the crisp dried seaweed sheets you’ll find wrapped around onigiri rice balls to delicate powdered varieties used as seasonings. But don’t worry if you can’t tell your kombu from your wakame! Our beginner’s guide to Japanese seaweed will go over everything you need to know about this delicious and nutritious aspect of the country’s food scene. So, let’s dive in!

A close up image of a black pair of chopsticks lifting thin strands of bright green seaweed

What is nori?

Nori is probably the variety of seaweed that people outside of Japan are most familiar with, because (as we’ll see below) it’s commonly used to wrap onigiri and sushi, as a topping for bowls of ramen, and as a condiment with many other dishes. However, nori is just one of many different types of Japanese seaweed, each of which has its own unique texture, flavor and appearance. This is what makes seaweed such a diverse and versatile part of Japanese cooking.

Two onigiri rice balls wrapped in a strip of nori seaweed, on a black plate with flowers in the background

What is Japanese seaweed called?

So, if it’s not all ‘nori’, what is edible Japanese seaweed called? Well, the general Japanese word for seaweed is kaisō (海藻), but each type has its own name. We’ll go through the most common varieties below so that you know what to expect! Seaweed has been an important part of Japanese cuisine for hundreds if not thousands of years and can be either harvested from where it naturally grows or deliberately cultivated. How is Japanese seaweed made? This also depends on the type, because they grow in different locations and can be eaten both fresh and dried. 

A bowl of udon noodles, topped with a pile of seaweed, tofu and spring onions

Types of Japanese Seaweed

Seaweed can be broadly divided into three main categories: red macroalgae, green macroalgae and brown macroalgae. There are many different species within each, including several that feature prominently in Japanese cuisine. Here are 10 of the most common varieties of Japanese seaweed you’re likely to encounter:

  1. Nori
  2. Aonori
  3. Wakame
  4. Hijiki
  5. Kombu (kelp)
  6. Mozuku
  7. Mekabu
  8. Umi budou
  9. Arame
  10. Kanten (agar agar)

1. Nori

Nori is the instantly-recognizable dried seaweed that’s wrapped around onigiri and certain types of sushi. It’s made in a similar process to paper, with the seaweed being cut up into fine pieces after harvesting and then pressed into very thin sheets to be dried and roasted. Thin strips are often served as a condiment or ramen topping, and you’ll also find shredded nori (kizami nori) used as a garnish on all sorts of dishes.

Five thin green sheets of nori seaweed fanned out on a white plate

2. Aonori

Aonori, or green laver, is a type of dried seaweed that’s been ground up into a fine powder. It’s really easy to use in cooking, because all you need to do is sprinkle it on top of savory dishes such as yakisoba and okonomiyaki as a garnish. The vibrant green color, umami taste and fragrant aroma will definitely enhance your meal!

A pile of green aonori seaweed flakes on a white background

3. Wakame

With broad fronds and a deep green color, wakame is a common ingredient in miso soup and side dishes such as seaweed salad. It has a mild umami taste with a hint of sweetness, and a slightly chewy satiny texture.

Wakame is often sold dried, and you can rehydrate it by soaking it in water before cooking with it. You’ll find that it expands quite a bit, so take care not to use too much!

An overhead image of a square white bowl full of dark green seaweed

4. Hijiki

This short, thin, dark brown seaweed grows along rocky coastlines, and in its dried form looks a little bit like black tea leaves. Hijiki has a subtle earthy, nutty flavor, and should be rehydrated before cooking. One of the most common seaweed recipes featuring it is hijiki no nimono, a seaweed salad in which hijiki is simmered in soy sauce, mirin and dashi, along with thin strips of carrot and deep-fried tofu (aburaage).

A close up image of a salad in a white bowl, with thin strands of dark brown hijiki seaweed and other vegetables

5. Kombu 

Also known as kelp, the thick strands of kombu seaweed are dark green with a leathery texture and rich umami flavor. It’s mainly cultivated in the northern prefecture of Hokkaido, and is one of the principal ingredients in Japan’s famous dashi soup stock. Kombu can also be sliced up and simmered in mirin, sugar and soy sauce, to be served as an accompaniment to rice or used as the filling for a rice ball. It's even possible to drink it as a tea!

A close up of long, thick strands of dark green seaweed topped with chopped spring onion

6. Mozuku

Mozuku is a brown type of seaweed that grows in Japan’s southernmost prefecture of Okinawa. It has a mild flavor, slightly slimy texture, and long thin leaf strands that look a bit like noodles. You can enjoy mozuku raw or cooked, and it’s often served seasoned with vinegar as a side dish. 

A close up image of a glass bowl full of light brown mozuku seaweed, with a pair of wooden chopsticks lifting some up

7. Mekabu

Mekabu is the flowering part of the plant that wakame comes from, but has a slimy texture that’s more similar to mozuku. It consists of soft and thin green strands, and goes well in a seaweed salad or paired with ponzu (a citrus and soy sauce dressing) as a side dish.

An overhead image of a bowl of soba noodles, topped with mekabu seaweed with sesame seeds, cucumber and spring onions

8. Umi budou

Literally translated as ‘sea grapes’, umi budou is a true Okinawan specialty. The stems are covered in tiny green spheres that look a little bit like caviar, and burst pleasantly in your mouth to release a hit of salty goodness. Umi budou is best served fresh, and seasoned with a touch of vinegar, ponzu, or soy sauce.

A small serving of green umibudou and wakame seaweed on a dark brown and cream rectangular plate

9. Arame

Similar to hijiki, arame is dark in color and comes in thin strips. It has a delicate and slightly sweet flavor that makes it perfect for seaweed newbies, and can be added to all kinds of dishes from salads to noodles or stir-fries.

A close up image of a pile of dried, thin dark brown strands of arame seaweed

10. Kanten

Kanten, also known as agar agar, is a little different to the other types of seaweed on this list because it’s flavorless and used a thickening or gelling agent rather than eaten on its own. It’s a vegan-friendly alternative to gelatin, and can be found in traditional Japanese desserts and wagashi sweets such as yokan and anmitsu.

Three rectangles of red yokan sweets on a square white dish, with flowers in the background

The health benefits of Japanese seaweed

In addition to its rich flavor, seaweed is a highly nutritious ingredient to include in your diet and offers a wealth of potential health benefits. This is because it’s a great source of fiber as well as containing plenty of key vitamins and minerals, including iodine, the amino acid tyrosine, and antioxidants. So, exactly what is Japanese seaweed good for? Here are just some of the many possible ways that eating seaweed benefits you:

  • Supports thyroid function
  • Protects your heart
  • Lowers blood pressure
  • Promotes gut health
  • Boosts your immune system
  • Balances blood sugar levels
  • Assists with weight loss

Seaweed recipes

In Japan you’ll find plenty of seaweed in almost every supermarket you visit, however if you live overseas you can order lots of different types of dried seaweed online instead.

Including it in your cooking is a fantastic way to add an extra depth of flavor and make your Japanese dishes more authentic. There are loads of delicious seaweed recipes you can try, from soups to seaweed salad, so you’re sure to find something that tantalizes your taste buds!

Three rolls of sushi stacked in a pyramid on a bamboo rolling mat

There’s so much to explore when it comes to Japanese seaweed, whether you’re tucking into it at restaurants or having a go at using it to create authentic dishes at home. It’s super healthy and adds a fantastic depth of flavor, so work your way through the types of seaweed on this list and see which you enjoy the most! 

We strive to be as accurate as possible and keep up with the changing landscape of Japan’s food and travel industries. If you spot any inaccuracies, please send a report.
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Ashley Owen
Ashley is a freelance travel writer from the UK who spent the last two years living in Japan, and is about to embark on her next adventure to New Zealand. She's always on the lookout for exciting new vegan treats wherever she goes!
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