Brassica rapa var. nipposinica is a leafy vegetable cultivar within the species Brassica rapa of the family Brassicaceae, commonly known as mizuna or Japanese mustard greens. The genus name Brassica derives from the Latin word for cabbage and related cruciferous plants, while the species epithet rapa comes from Latin meaning “turnip,” reflecting the plant’s close relationship to root crops in the same species complex. The varietal name nipposinica combines “Nippon,” an older romanization of Japan, with “sinica,” meaning “of China”. Mizuna is believed to have been developed in Japan, particularly around the Kyoto region, through selection of leafy forms of Brassica rapa.

The plant produces clusters of deeply serrated, feathery leaves with slender stems, forming a loose rosette rather than a dense head. It is a cool-season crop that grows rapidly and is well adapted to temperate climates. Compared to other mustard greens, mizuna has a relatively mild, slightly peppery flavor and a tender texture, making it suitable for both raw and cooked applications. It is widely cultivated in Japan and increasingly grown in other parts of the world as a salad green.

As a food source, Brassica rapa var. nipposinica is used as a fresh leafy vegetable in salads, stir-fries, soups, and pickled dishes. In Japanese cuisine, it is commonly included in hot pot dishes (nabe), lightly sautéed preparations, and mixed vegetable dishes, where it contributes both texture and a subtle mustard-like pungency. It can also be eaten raw, often combined with other greens for its crisp structure and mild flavor.

Chemically, mizuna contains glucosinolates typical of Brassicaceae plants, which can be enzymatically converted into isothiocyanates when the plant tissue is cut or chewed, contributing to its mild pungency and potential health effects. It also contains vitamins such as vitamin C, vitamin K, and folate, as well as carotenoids and flavonoids that provide antioxidant activity. These compounds have been studied for roles in supporting detoxification pathways and reducing oxidative stress in experimental contexts.