The only place it can be found growing naturally is along Japanese mountain streams.

Sushi without wasabi? Climate change reduces Japanese farms’ output

Specific conditions such as amount of shade, temperature, and soil minerals must be met for these plants to thrive. They need a constant supply of running spring water and can only tolerate temperatures between eight degrees and 20 degrees Celsius.

Although wasabi grows mainly in Japan, The Wasabi Company, in Europe, is among the first to grow it commercially.

Wasabi must grow for about 18 months before it can be harvested. Harvesting is a time-consuming process, it has to be done completely by hand. The plant is broken and cleaned up to get to the stem. A special grater with very fine teeth is used to turn it into a paste.

A farm-grown eel in Hamamatsu city, Japan. Photo: Getty Images

2. Eel

Unagi, or freshwater Japanese eel, can cost more than bluefin tuna. It has been a delicacy for thousands of years, but overfishing has led to a decline in eel populations, contributing to high prices.

Young eels are caught and raised on farms, and require daily monitoring. If disease spreads or accidents happen, the whole batch can be lost.

Feeding the eels two or three times a day is also expensive. They eat a mixture of fish meal, wheat, soybean meal and fish oil. After six to 12 months, the eels are big enough to be sold.

Puffer fish in Japan, used to make the dish fugu, which if prepared incorrectly, can kill you. Photo: Shutterstock

3. Puffer fish

Fugu, or puffer fish, is a delicacy served across Japan. The most prized and poisonous is the torafugu, or tiger puffer fish. In Haedomari Market in Yamaguchi prefecture, it’s auctioned off through secret bids.The tetrodotoxin found in fugu is more toxic than cyanide, and people can be killed by badly prepared fish. The Japanese government places strict regulations on who can prepare fugu, and fugu chefs go through extensive training.

The careful preparation process and overfishing are causing it to become more expensive.

Taiyo no Tamago mangoes can sell for as much as US$4,000 for a pair. Photo: Getty Images

4. Mangoes

Sweet mangoes, known as Taiyo no Tamago [egg of the sun], are farmed in Miyazaki prefecture. Market auctions sell these mangoes for as much as US$4,000 for a pair.

Plenty of sunlight is needed to make them plump and red. Their skin must be unblemished with no hints of green, and they must weigh more than 350 grams and have at least 15 per cent sugar content.

Ruby Roman table grapes are among the most expensive grapes in Japan, selling for anything between US$490 and US$450 a bunch. Photo: Getty Images

5. Ruby Roman grapes

Ruby Roman grapes are a delicacy grown in Japan. One bunch can sell for US$90 to US$450. They stand out for their size, uniform colour, and taste.

The grapes are cultivated in greenhouses, so farmers can have better control of their growth. They’re monitored to ensure each grape in the bunch is identical.

Sea urchin is highly prized in Japan, and can cost from US$100 to US$500 per 200g tray. Photo: Shutterstock

6. Sea urchin

Sea urchin, or uni, is prized in several parts of the world for its flavour. The spiky shells of sea urchins are cracked open for the gonads, which are the sex organs that produce roe.

One 200-gram tray can cost up to US$100. In Japan, some can sell for five times that. Red sea urchins are hand-harvested by divers.

The amount of kelp in the water affects how many good-quality urchins can be harvested. When there is a lack of kelp, the urchins are less marketable.

Farming uni hasn’t been perfected yet, so it remains a highly sought-after food.

Growing Japanese melons is a painstaking process, which is reflected in their price. Photo: Shutterstock

7. Melon

Japanese melons are largely grown in central Japan, and can cost over US$200. In 2019, two melons from Hokkaido in northern Japan sold for just over US$45,000 at auction.

It takes 100 days for one of these crown melons to fully grow, and it requires constant attention and care. Its outside pattern and sugar content determine which grade it falls into.

The melons are grown in raised beds and kept separated from the ground. This allows the farmers to control the exact amount of water. Air-conditioning and heating keep the temperatures constant so the melons can be harvested year-round.

Despite the cost, there is high demand for the fruit across Japan. They are a luxury that plays a big part in Japan’s gift-giving culture.

Japanese matsutake mushrooms can cost up to US$500 per kilogram. Photo: Shutterstock

8. Matsutake mushrooms

Matsutake mushrooms are harvested once a year in Japan. If the harvest is low, they can cost up to US$500 per kilogram.

These mushrooms grow in the ground connected to the roots of red pine trees. They are hand-picked and can be difficult to find because they blend into the forest floor.

Changing habitats caused by drought, high temperatures and insect damage can affect the quality of each harvest. When there is a bad harvest, the prices substantially increase.

Today, Japan imports a majority of its matsutake mushrooms from places like China and South Korea.