or Japanese mustard spinach (''Brassica rapa'' var. ''perviridis'') is a

leaf vegetable Leaf vegetables, also called leafy greens, pot herbs, vegetable greens, or simply greens, are plant leaves eaten as a vegetable, sometimes accompanied by tender petioles and shoots. Leaf vegetables eaten raw in a salad can be called salad gre ...

. It is a

variety Variety may refer to: Arts and entertainment Entertainment formats * Variety (radio) * Variety show, in theater and television Films * ''Variety'' (1925 film), a German silent film directed by Ewald Andre Dupont * ''Variety'' (1935 film), ...

of ''

Brassica rapa ''Brassica rapa'' is a plant species growing in various widely cultivated forms including the turnip (a root vegetable); napa cabbage, bomdong, bok choy, and rapini. ''Brassica rapa'' subsp. ''oleifera'' is an oilseed which has many common n ...

'', the plant

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...

that yields the

turnip The turnip or white turnip ('' Brassica rapa'' subsp. ''rapa'') is a root vegetable commonly grown in temperate climates worldwide for its white, fleshy taproot. The word ''turnip'' is a compound of ''turn'' as in turned/rounded on a lathe and ...

, mizuna,

napa cabbage Napa cabbage (''Brassica rapa'' subsp. ''pekinensis'' or ''Brassica rapa'' Pekinensis Group) is a type of Chinese cabbage originating near the Beijing region of China that is widely used in East Asian cuisine. Since the 20th century, it has als ...

, and

rapini Rapini or broccoli rabe () is a green cruciferous vegetable, with the leaves, buds, and stems all being edible; the buds somewhat resemble broccoli, but do not form a large head. Rapini is known for its bitter taste, and is particularly associ ...

. It is grown commercially in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

and

Taiwan Taiwan, officially the Republic of China (ROC), is a country in East Asia, at the junction of the East and South China Seas in the northwestern Pacific Ocean, with the People's Republic of China (PRC) to the northwest, Japan to the no ...

. It is a versatile vegetable that is cooked and eaten in many ways. The plant is also used for

fodder Fodder (), also called provender (), is any agricultural foodstuff used specifically to feed domesticated livestock, such as cattle, rabbits, sheep, horses, chickens and pigs. "Fodder" refers particularly to food given to the animals (includ ...

in some Asian countries. Katori shrine of Shin-Koiwa

The name 'komatsuna' means 'greens of Komatsu' in Japanese, a reference to the village of in

Edogawa, Tokyo is a special ward located in Tokyo Metropolis, Japan. It takes its name from the Edo River that runs from north to south along the eastern edge of the ward. In English, it uses the name Edogawa City. The easternmost of the wards, it shares b ...

, where it was heavily grown during the

Edo period The or is the period between 1603 and 1867 in the history of Japan, when Japan was under the rule of the Tokugawa shogunate and the country's 300 regional '' daimyo''. Emerging from the chaos of the Sengoku period, the Edo period was character ...

. It was named by

Tokugawa Yoshimune was the eighth '' shōgun'' of the Tokugawa shogunate of Japan, ruling from 1716 until his abdication in 1745. He was the son of Tokugawa Mitsusada, the grandson of Tokugawa Yorinobu, and the great-grandson of Tokugawa Ieyasu. Lineage Yoshi ...

, the eighth

shogun , officially , was the title of the military dictators of Japan during most of the period spanning from 1185 to 1868. Nominally appointed by the Emperor, shoguns were usually the de facto rulers of the country, though during part of the Kamakura ...

, who visited Edogawa in 1719 for hunting and stopped at the local Katori Shrine for lunch. The shrine priest served him soup with a rice cake and a local leaf vegetable. The shogun was impressed by the flavor of the vegetable so much and named it komatsuna, after the nearby Komatsu River (which gives Komatsugawa its name). Till this day, the Shin-Koiwa Katori Shrine offers komatsuna to the deities on New Year's Eve. People who come to the shrine to pray on New Year's Day are also given komatsuna for good luck in the new year. Since the days of the shogun, komatsuna has been bred to have a sweeter taste. The old variety thought to have been served to the shogun is not widely available. That variety is called ''Goseki bansei''. It grows faster and has bigger but fewer leaves than ordinary komatsuna, and a strong, spicy flavor. The leaves of komatsuna may be eaten at any stage of their growth. In a mature plant they are dark green with slender light green stalks, around 30 centimeters (12") long and 18 cm (7") wide. It is most often grown in the spring and autumn, as it cannot endure

extreme heat A heat wave, or heatwave, is a period of excessively hot weather, which may be accompanied by high humidity, especially in oceanic climate countries. While definitions vary, a heat wave is usually measured relative to the usual climate in the ...

or cold for more than a short time. Although nowadays it's grown year-round in green houses.

Cooking

Komatsuna has a fresh, sweet taste and a crunchy texture. It is a very versatile vegetable and can be eaten raw,

pickled Pickling is the process of preserving or extending the shelf life of food by either anaerobic fermentation in brine or immersion in vinegar. The pickling procedure typically affects the food's texture and flavor. The resulting food is called ...

, stir-fried, boiled, used fresh in salads, or added to soups. It is popular in soups as it can stay firm after being simmered. It is an excellent source of

calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar ...

, vitamin A, and vitamin C.

References

Leaf vegetables Japanese vegetables Brassica {{vegetable-stub

Cooking

See also

References