Wasabia Japonica, better known as wasabi, is a plant native to Japan that is harvested for its lumpy rhizome, which is predominately used as a popular sushi condiment. The plant grows only in damp areas, usually in streams or artificial water beds.
It is difficult to grow and takes up to two or three years to mature. The rhizome is typically grated against textured sharksin that is attached to a wooden board. Grated wasabi develops its signature pungency after a couple of minutes, but most of its flavor tends to disappear quickly, and true wasabi always needs to be freshly grated, right before it is served. Though wasabi paste is an internationally acclaimed sushi condiment, due to its cost, it is estimated that only 5% of the restaurants use fresh wasabi, while the rest opt for a much cheaper combination of grated horseradish and green food coloring, or various alternatives prepared with dry wasabi powder.