Karashi, also called wa-garashi (literally ‘Japanese mustard’, to distinguish it from yo-garashi, ‘Western mustard’), is a type of mustard used as or in Japanese sauces, condiments and marinades. It is a hot, slightly bitter mustard, with a distinctive peppery taste typical of plants like horseradish. Thanks to both the species and the preparation methods, karashi is a spicier and more potent condiment than mild yellow mustard preparations, though it does bear some resemblance to hot English mustard. Chinese hot mustard powders are virtually identical to karashi mustard.
Karashi is made from the seeds of Brassica juncea (Western-style yellow mustard is generally made with the milder white mustard plant, Sinapis alba). The entire plant is popular as a vegetable throughout much of Asia, though it is the seeds which are especially prized in Japan.
Karashi mustard is available as a powder or a paste, and is very simple to use and prepare in either form.
Karashi is written 芥子, 辛子, or からし in Japanese.