The Wonders of Nori Seaweed According to a 100-Year-Old Seaweed Shop

Have you ever tried Japanese “nori” seaweed? These crunchy, dark-green, paper-thin sheets have long played a part in Japan’s food culture, from adorning sushi and onigiri rice balls to being enjoyed as-is. For this edition of our deep-dive "Culture of Japan" series, we traveled to the long-established Ito Noriten in Tokyo’s Tsukiji to learn how to pick the perfect nori, the best way to eat it, and more!

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*This article was written with the cooperation of Ito Noriten.

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Nori - A Treasure From the Sea

Nori is everywhere in Japan – from household cooking to fancy restaurants, on onigiri rice balls to sushi, "ochazuke" (rice with tea), salads, pasta, and more. Nori is high in "umami components" (three types of amino acid constituents including glutamic acid), and has been loved in Japan for generations.

Nori is made from a type of seaweed that grows in the ocean around the coastline, and comes in a variety of appearances and flavors. The seaweed used to make nori is rinsed and finely chopped before being washed in a frame with water and left to dry and set, a process similar to traditional Japanese paper-making.

Nowadays, Japanese nori is largely produced through aquaculture. However, unlike fish, nori farmers are not guaranteed stable quantities simply by providing food. The growth of nori instead depends on outside factors, such as the temperature of the atmosphere and sea water, and the amount of precipitation, which can affect color, fragrance, flavor, and texture. For this reason, it is imperative that nori wholesalers and shops are able to expertly judge the quality of nori.

Interestingly, the shape and standard size of nori are the same in supermarkets across Japan, even if the maker or production area is different. This is due to a 300-year-old process that began in the Edo period (1603 - 1867), which mimics the shaping and straining process used to make Asakusa "washi" (traditional Japanese paper).

The dimensions of nori were standardized to simplify the drying process and to make it thin for easy transportation. The “full-size” nori labeled on commercial packages is 21 cm (length) and 19 cm (width).

Where Can I Buy Nori in Japan?

Nori can be easily found wrapped in clear plastic lining the shelves of supermarkets throughout Japan. There is a wide variety available, including dried nori, seasoned nori, shredded nori, and so on. However, if you’re after the most delicious, authentic nori, we recommend heading to a nori wholesaler or specialty shop.

Visiting a Professional Nori Wholesaler

As mentioned, the quality of nori is greatly affected by the environmental conditions of each given year, so purchasing it from an experienced professional at a long-established specialty store or wholesaler is your best bet at acquiring the good stuff.

These experts source nori from seaweed fishermen and producers across the country, and are able to separate the best from the rest with ease. Prominent nori production areas in Japan include the Ariake Sea by Saga, Fukuoka, and Kumamoto Prefectures in Kyushu, the Seto Inland Sea, Tokyo Bay, and Sendai Bay in Miyagi Prefecture. Once acquired, the nori is dried, roasted, and packaged to be sold to restaurants and general consumers.

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Ito Noriten - A 100-Year-Old Nori Shop in the Kanto Area

Owing to my passion for Japanese cuisine, I’ve used and enjoyed nori on countless occasions. Despite this, I had yet to dive into the intricacies of this aquatic treat, and had simply procured it at random. Longing to close my knowledge gap, I made my way to a long-established, Kanto-based nori shop to learn directly from the source.

Established in the Ryogoku area in 1923, Ito Noriten is a 100-year-old nori specialty shop passed down the family through the generations. It now has locations in the legendary Tsukiji Outer Market, famed as the "Kitchen of Tokyo," and Ichikawa in Chiba Prefecture.

Ito Noriten specializes in roasted nori carefully selected and brought in from the Ariake Sea in Kyushu. This particular nori is known for its delectable flavor and satisfying texture, making it perfectly enjoyable on its own or as a wrapping for "temaki-zushi" (cone-shaped sushi). Ito Noriten also sells dried nori cut for different dishes, as well as easy-to-eat canned nori perfect as a snack or souvenir.

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How to Choose the Best Nori, According to a Nori Shop Owner

The 100-year-old Ito Noriten is currently run by 4th generation owner Shingo Ito. Ito began helping out at Tsukiji during his days off while in middle school, and it has been more than 15 years since he took over his family business. Unlike his father, the previous owner, who was solely devoted to the art of nori roasting, Ito prioritizes creating face-to-face relationships with his customers.

Seeking to "spread the appeal of nori to the world" and "create an environment where everyone can enjoy nori," Ito not only pours his energy into retail sales, but has also opened an official online shop to optimize communication with customers. When he is not assisting both Japanese and international customers, he uses his spare time to visit elementary schools as a nori instructor.

With such a wealth of experience and knowledge, we were certain that there was no one better than Ito to teach us how to recognize high-quality nori.

When Is Nori the Most Delicious?

There are several factors that need to be considered when growing nori. Arguably the most important is temperature, as seaweed will not grow well if it is too hot or cold. Being a natural product, nori also has a peak season, which can vary slightly depending on the area.

Generally speaking, nori grows the most rapidly from October, when the sea water begins to cool, until the following March. Fishermen normally begin harvesting in late November, and the nori gathered up until early December is called "hatsu-tsumi" or "ichiban-tsumi," which both translate as "first pick," renowned for its soft texture and sweet fragrance. Nori continues to grow until April, and is harvested a number of times. With each harvest, the texture becomes more coarse, and the flavor gradually deteriorates, making it not as desirable as young nori. If you wish to taste the best nori available, try purchasing it in December.

The Characteristics of Delicious Nori

To Ito, high-quality nori possesses three characteristics: a dark luster, deep savory flavor, and melt-in-the-mouth texture. However, as it is difficult for regular people to differentiate such color and luster, Ito showed us two types of nori (shown above) for comparison. The piece on the right is of higher quality as it has a darker complexion, while the left is clearly lighter in color, demonstrating its inferior quality.

A Dark Luster

When selecting nori, first look for deep, lustrous greens that almost appear black. This is a common characteristic for nori harvested from November to early December, or during the second harvest from January to February. Light yellow-green nori without any sheen was likely harvested towards the end of the period (usually costing at least 600 yen for 10 sheets).


While nori should be dark, also look for thin sheets that let the light shine through. This indicates a high-quality crispness often sought after by classy Japanese restaurants. On the other hand, thicker nori is often used at cheaper, everyday establishments.

・Packaging, Small Holes, and Price

As the flavor and grade of nori depends on when it was harvested, look for packages with labels that have "初摘み" (hatsu-tsumi) or "一番摘み" (ichiban-tsumi), which both mean "first pick." Alternatively, some may have "新海苔" (shin-nori), translating as "new nori," along with the production year.

Others will include symbols like "丸" or "◯" (both read as "maru"). As soft nori sprouts shrink when dried, small holes can also appear in the surface of nori sheets. In the nori world, these holes are called "maru," and often indicate fresher, more delicious, and expensive nori. For example, nori with a package that reads "一番摘みの◯" (ichiban-tsumi no maru) can go for around 1,000 yen for 10 sheets, and would be considered high-grade.

However, just because the package is expensive or comes from a reputable brand doesn’t mean that the nori inside is good. Everyone has different tastes, and the best way to find your own perfect nori is to compare different varieties while making note of your favorites.

Pay Attention to the Packing Material

While nori found in markets is generally packaged in plastic, this lets in light that can alter the temperature and humidity, making it far from ideal. For this reason, Ito Noriten prefers aluminum packaging equipped with a drying agent to protect the delicate nori from humidity. If available, Ito recommends opting for nori wrapped in similarly protective packaging.

The Best Way to Enjoy Nori

Now that you know what to look for, how can you get the most out of your nori? Surprisingly, Ito enthusiastically explained to us that the best way to eat nori is none other than as-is! Unlike Korean-style nori, which is often seasoned with sesame oil and salt, Japanese nori (especially from the Kanto region) is usually left unseasoned, highlighting the savory and oceanic flavors. This makes it easy to pair with all types of food, including rice, noodles, salads, and more.

It’s also important to mention that nori sheets have a smooth "front" and a rough "back." If eating nori with rice, Ito recommends placing the glossy side face-down and heaping the rice atop the rougher surface before rolling it up for a grander appearance!

How to Save Opened Packs of Nori

Nori is incredibly sensitive to light and humidity and can lose its texture and shape if not stored properly after opening. While it’s best to finish all the nori as soon as possible, Ito mentioned that it can also be stored in an aluminum package with a drying agent in a cool, dry place away from direct sunlight. Fortunately, nori does not require refrigeration and can be stored at room temperature, so if you properly protect it from humidity, its crispness can be retained from 3 to 5 months.

If your nori does go soggy, instead of throwing it out, we recommend using it to make salty-sweet "nori tsukudani," a traditional Japanese paste-like condiment that pairs amazingly with rice. To make it, combine nori, water, soy sauce, sugar, and cooking sake in a pot and bring it to a boil.

Relish the Marine Bounties of the Japanese Archipelago

Since ancient times, nori has played an invaluable role in Japanese cuisine. Along with being nutritious and healthy, it brims with umami flavor, a satisfyingly crisp texture, and alluring fragrances. Nori is also extremely lightweight, making it a great souvenir to bring back from Japan! We hope this article will help you find the perfect nori to enjoy the tastes of Japan to their fullest!

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Kanto Feature

The information in this article is accurate at the time of publication.

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About the author

Fuchi Pan
Born in Taiwan, currently living in Tokyo. Yearning for a life surrounded by handmade goods and things she loves.
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