is a type of mustard

Mustard (condiment)

Mustard is a condiment made from the seeds of a mustard plant...

 used as a condiment

Condiment

A condiment is an edible substance, such as sauce or seasoning, added to food to impart a particular flavor, enhance its flavor, or in some cultures, to complement the dish. Many condiments are available packaged in single-serving sachets , like mustard or ketchup, particularly when supplied with...

 or as a seasoning

Seasoning

Seasoning is the process of imparting flavor to, or improving the flavor of, food.- General meaning :Seasonings include herbs and spices, which are themselves frequently referred to as "seasonings"...

 in Japanese cuisine

Japanese cuisine

Japanese cuisine has developed over the centuries as a result of many political and social changes throughout Japan. The cuisine eventually changed with the advent of the Medieval age which ushered in a shedding of elitism with the age of shogun rule...

. Karashi is made from the crushed seeds of Brassica juncea

Brassica juncea

Brassica juncea, also known as mustard greens, Indian mustard, Chinese mustard, and leaf mustard, is a species of mustard plant. Subvarieties include southern giant curled mustard, which resembles a headless cabbage such as kale, but with a distinct horseradish-mustard flavor...

. Karashi is usually sold in powder form or paste form in tubes. Karashi in powder form is prepared for use by mixing with lukewarm water to a paste and leaving it covered for a few minutes.

Karashi is often served with tonkatsu

Tonkatsu

Tonkatsu , invented in the late 19th century, is a popular dish in Japan. It consists of a breaded, deep-fried pork cutlet one to two centimeters thick and sliced into bite-sized pieces, generally served with shredded cabbage and/or miso soup...

, oden

Oden

Oden is a Japanese winter dish consisting of several ingredients such as boiled eggs, daikon radish, konnyaku, and processed fish cakes stewed in a light, soy-flavoured dashi broth. Ingredients vary according to region and between each household...

, natto

Natto

is a traditional Japanese food made from soybeans fermented with Bacillus subtilis. It is popular especially as a breakfast food. As a rich source of protein and probiotics, nattō and the soybean paste miso formed a vital source of nutrition in feudal Japan. Nattō can be an acquired taste because...

, and shumai. Karashi can be used as part of a dipping sauce when mixed with mayonnaise, called karashi mayonnaise or with vinegar and miso

Miso

is a traditional Japanese seasoning produced by fermenting rice, barley and/or soybeans, with salt and the fungus , the most typical miso being made with soy. The result is a thick paste used for sauces and spreads, pickling vegetables or meats, and mixing with dashi soup stock to serve as miso...

, called karashi su miso.
It is also used to make pickled

Tsukemono

are Japanese pickles. They are served with rice as okazu with drinks as an otsumami , as an accompaniment to or garnish for meals, and as a course in the kaiseki portion of a Japanese tea ceremony....

 japanese eggplant, called karashi-nasu.
One of Kumamoto's best-known meibutsu

Meibutsu

Meibutsu is a Japanese term for famous products associated with particular regions. Meibutsu are usually items of Japanese regional cuisine, although the category includes local handicrafts. Meibutsu typically have a traditional character, although contemporary products may qualify as meibutsu...

 is Karashi Renkon - a Lotus Root stuffed with karashi and served in slices.