Wasabi

Wasabi, Eutrema japonicum, formerly Wasabia japonica, is a plant in the family Brassicaceae, related to horseradish and mustard, native to Japan, the Russian Far East including Sakhalin, and the Korean Peninsula, growing naturally along stream beds in mountain river valleys. It has large leaves on long, thin stalks measuring 3 to 6 inches in each dimension with palmate veins, and is cultivated for its rhizomes, which are ground into a pungent paste eaten as a condiment with sushi and other foods; its flavor stimulates the nose more than the tongue, distinguishing it from chili heat, and resembles hot mustard or horseradish. Its earliest documented use dates to the eighth century, and its popularity in English-speaking countries has grown steadily since around 1980 alongside sushi, though authentic wasabi remains expensive and difficult to cultivate, leading many markets outside Japan to substitute dyed western horseradish instead.