[Nagoyankee]

This year's Golden Week (as it's called in Japan) is April 29 thru May 6. You may want to avoid that period if you want to see Tokyo in its "normal" self.

Many Tokyoites return to their hometowns or go on vacations. A lot of smaller, family-owned stores and restaurants will be closed. But larger stores, big chain eateries, and practically all restaurants located inside hotels will be open so it's not like you will starve or anything. As a matter of fact, some people will enjoy Tokyo more during the Golden Week because it will be considerably less crowded.

The biggest problem that I can think of is when a foreign tourist wants to take day-trips out of Tokyo on trains during that period. The trains will be packed with no more reserved seats available. But inside Tokyo, it will be heaven with no rush hours to worry about.