Most of the wasabi on the market is fake. Two brothers grow the original type in Tokyo

- Most people are familiar with wasabi, the green Japanese paste famous for its sour taste and sharp effect on the nose, associated with sushi. It has spread beyond Japanese restaurants to become an ingredient in cocktails and snacks.

But few sushi lovers have ever tasted authentic wasabi, as they are often served a mixture of horseradish and green food coloring instead. The bulk of wasabi sold in the United States and other markets is counterfeit, and even in Japan the original type makes up only a small percentage of the supply.

Mutsukari, a Michelin-starred restaurant in Tokyo's Ginza district, is an exception, since it opened in 2004 and has relied on "hon wasabi", meaning authentic wasabi. Chef Yoshihisa Akiyama told Ofoq News: “Fresh wasabi initially has a sour taste and pungent smell, but it quickly leaves a soft, smooth and creamy sensation on the tongue,” indicating its difference from imitation paste, which has a sharp taste.

Akiyama's omakase menu, in which the customer leaves the choice of dishes to the chef, relies on local ingredients, especially traditional Japanese vegetables. He emphasizes that choosing the right dish to serve wasabi with can transform its flavour.

But obtaining native wasabi (Wasabia japonica) has become more difficult over the past two decades, due to aging farmers and a shortage of successors, as well as climate change and warming of the streams in which the plant grows. Wasabi's growth cycle takes two years, during which it needs stable water temperature and specific conditions for exposure to sunlight.

Its price ranges between $100 and $200 per pound, and it is not recommended to use it more than a week after harvesting, which prompts many people to choose imitation alternatives that are cheaper and longer lasting. “Fresh ingredients have a strong flavor of their own, so it's important to serve them quickly after harvesting,” Akiyama said.

“For wasabi, freshness is a requirement.” The chef sources his supplies from the Okutama region, less than 80 kilometers from Tokyo, where wasabi cultivation dates back to the Edo period (1603-1868).

He described the terraced stone fields there as a "treasure," noting that his current suppliers are the brothers Hitoshi and Tatsuya Tsunoe, known as "Tachan," and their partner, Momo Uchida. The art of growing wasabi Okutama was historically the third largest wasabi-growing area in Japan, but Typhoon Hagibis that struck in 2019 destroyed 150 farms, and only 50 of them have been rehabilitated to date.

“There are not enough people left to run these farms, so my brother and I thought that if we took on the task, we could help sustain wasabi cultivation in Tokyo,” said Tachan Tsunoi, 40. In 2020, the two brothers founded the Tokyo Wasabi Project, a private farm with about 5,000 plants that takes visitors on a daily tour to taste wasabi fresh from stream water.

The brothers follow the traditional Okutama method, building terraced fields that blend with the mountain topography, using small stones from the area to create planting beds. “Over time, the roots of the trees surrounding the stones intertwine and stabilize them, and then we can grow wasabi,” Tsunoi said.

Caring for the plant requires providing shade when the sun is intense, removing fallen leaves in streams, and protecting it from the cold in winter using “Canresha” net, made of black and light synthetic fibres. But climate change has made the task more difficult, according to Tsunoi, who explained that the intense summer heat increases the likelihood of plants rotting, while heavy rains sometimes wash away wasabi, and the decrease in snowfall in the winter leads to changing water conditions.

After two years of caring for these small agricultural areas scattered deep in the mountains, the time for harvest has come. Although wasabi's taste is strongest in winter, its harvest continues throughout the year.

“After harvesting wasabi by hand, we wash the plant and clean it with a knife to make it look neat,” Tsunoi said. “Next, we trim the stems to about 45 centimeters long, then put the produce in boxes and ship it directly to restaurants.”

Since wasabi is a fresh vegetable, it is best to use its rhizome within about a week of harvesting it. The fresher it is, the more vitality and flavor it retains.”

The farm supplies Chef Akiyama and a number of other establishments, including the Wasabi Shokudo food truck and the coffee brand Wasabi Coffee. The two brothers aspire to expand their production scope in the future.

Global spread: The global market value of original and imitation wasabi was estimated at about $468.8 million in 2025, with expectations that it will rise to about $924 million by 2034. Tsunoi pointed out that research has monitored potential health benefits of wasabi, including: In addition to potential benefits: With increasing local and global demand, the two brothers are seeking to increase production and use agricultural technology.

“Even though we are located in a major urban area, we grow wasabi outdoors, in a natural environment, and we rely on labor at all stages of the work,” Tsunoi said. “In the future, we aspire to combine traditional farming methods with advanced agricultural technology, such as drones.”

The wasabi industry is already seeing an expansion in the use of crop monitoring drones, precise sensors and automated systems for controlling environmental conditions. But Okutama first needs to improve connectivity and 5G coverage, which would allow the two brothers to increase production while maintaining traditional farming methods.

On the other hand, the remote nature of the region is an attractive factor for tourists, as about half of the participants in mountain tours come from outside Japan. Tsunoi said that the popularity of wasabi is increasing globally year after year, which strengthens his hopes for exporting it in the future.