Napa cabbage is a vegetable that is eaten widely in East Asia, including in China, the Korean peninsula and Japan. It was first brought to Japan from China in the Meiji period. Today, napa cabbage is mainly produced in Ibaraki, Nagano, and Gunma prefectures, but Hokkaido ranks in with the third largest shipment volume. Napa cabbage is an essential ingredient in hot pots and pickles, giving it a strong reputation as a winter vegetable, but during the summer, napa cabbage grown in Hokkaido’s cool climate is shipped across Japan to stores and markets.
Napa cabbage contains a good balance of nutritional elements and it is particularly rich in calcium, which helps to rid the body of sodium. This is why people with high blood pressure should include cabbage in their diet. However, calcium tends to seep out when heated, so napa cabbage should be cooked in soups and broths. Napa cabbage also contains vitamins A, B1, B2, and C, and iron and dietary fiber.
Napa cabbage is mostly grown in Iwamizawa City and the Sorachi area as well as the Tokachi area.
■Map / Main producing municipalities
Iwamizawa City, Makubetsu Town, Shimizu Town, Kitami City, Naganuma Town, Date City, Ebetsu City, Shari Town, Hokuto City, Nayoro City
There are between 40 and 50 basic varieties of napa cabbage. Many of these varieties are grown in Hokkaido because it has the perfect growing environment with temperatures between 15 and 20 degrees Celsius. In recent years, mini napa cabbage, which are compact in size and easy to carry, have emerged and become quite popular at produce stands. Today the main type of napa cabbage grown has yellow inner leaves, but until around the 1970s most of the napa cabbage grown in Japan had white inside. Recently, napa cabbage is often sold pre-cut. This is because yellow napa cabbage are more popular than ever, as the yellow color appears particularly delectable and there is rising interested in Japan for eating colored vegetables.
Hokkaido-grown napa cabbage is shipped throughout Japan from summer to fall, with most having been grown outdoors. Some of this napa cabbage is also grown in greenhouses and tunnels so that the growing period and harvest can take place earlier.
Napa cabbage is mainly cultivated from March to October and it is harvested from May in greenhouses and from July outdoors. The season runs from July to October.