Japanese mustard from Tokachi – the challenge of cultivating for harvest

Kotani Koichi (70), a farmer from the village of Sarabetsu in the Tokachi region of eastern Hokkaido has begun cultivating white mustard with the aim of harvesting the crop. The mustard is often cultivated in Hokkaido for use as a fertilizer, but is rarely harvested as a crop in Japan. Over 90% of the raw materials used in the production of ‘grain mustard’ is imported. Kotani, who began cultivating the crop in 2015, is enthusiastic, saying “I want more people to know about Tokachi-made mustard”.

 Kotani carries out Tokachi-style large-scale upland farming, growing crops such as wheat, sugar beet and potatoes in 170 hectares of fields. On the other hand, he also cultivates hemp and rapeseed, and processes edible oil to sell in Hokkaido and beyond with the aim of creating direct links with consumers.

The yellow flowers of white mustard. Being able to see the flowers is one of the joys of growing it.
Kotani Koichi holding the yellow-colored white mustard seeds (foreground) graded in the colorful grader (background).

 White mustard is from the Brassicaceae family of plants, and has a yellow flower similar to rapeseed blossoms. It is cultivated widely around Hokkaido for fertilizer and viewing purposes, and Kotani also used it as a fertilizer in his fields before he found out it is seldom cultivated for harvesting in Japan.

Kotani decided to take up the challenge in 2015, and started from just 0.5 hectares. He could obtain the harvestable variety of seeds from overseas but was not familiar with the method of cultivation. He searched and read literature in English on the internet, and soon accumulated a thick pile of specialist journals full of cultivation results. Even so, work in the fields was difficult, with seeds having to be re-sown after being blown away in strong winds, as well as problems with disease and weeds. “At first it was just a succession of failures,” he says with a wry smile.

The seeds that are eventually harvested are shipped directly to restaurants in Hokkaido and beyond, where they are processed into grain mustard by the establishments themselves.

Homemade mustard served with a meat dish

 There are also other farmers in the Tokachi region who are following Kotani’s attempt to cultivate the crop. This year, Kotani plans to increase cultivation of experimental crops, including white mustard used as an ingredient of Japanese mustard, to 5 hectares. “If you live in Tokachi and can eat things from Tokachi that are delicious, it would be great. I want to produce things that make the consumers happy – that’s the driving force behind this.”


Sarabetsu Village