Ever wonder why Wasabi, that fiery green paste and indispensable sushi accompaniment, tastes so much like horseradish? Here’s why: because it IS horseradish.

Although we’ve learned to call it Wasabi, what we’re served in sushi restaurants in North America – and largely in Japan, too – is nearly always a mixture of horseradish and green coloring, with perhaps a little dry mustard, with possibly a very little bit of real Wasabi added in.

Why not offer the real deal? Because real wasabi, Wasabia japonica, is very rare. Even in its native Japan, demand constantly outstrips supply, and it’s expensive to import and notoriously tricky to grow.