Do you know what other whiskies will be at the tasting. Japan does not have very many producers, but Nikka, and Kirin and Suntory, the three main distillers, both put out a wide range of whiskies of variable quality. As you would expect, at the bottom end of the spectrum the whiskies can be excreble, and at the top end superb.
Keep an eye out for the older expressions of Hibiki (by Suntory), Taketsuru (by Nikka), and Yamazaki (also by Suntory), as they will provide you with a good cross-section of Japanese styles. If Yoichi is available, all the better.
Please report back on the tasting. I drank a lot of Japanese whisky over the last year and have my own preferences, but I would love to hear what your impressions are.