yoshikawa | oros grater small | design hideyoshi nagoya, junji yawata, aya sunagushi

If you have a source for real wasabi, you need the Oros grater: the rhizome, the root offshoot of the spicy Japanese water horseradish, is grated into a paste and often served with sushi. You can of course also use European horseradish or ginger, which will give you a fresher ingredient than the commercially available green tube paste.