If you come all the way to Japan, why don't you do something to enjoy Japan more?
There are a lot of seasonal events, local festivals, traditional culture to experience.

If you're coming in
spring, you shouldn't miss
cherry blossom viewing (hanami), especially if you're staying in Tokyo as there are a lot of great hanami spots.

In
summer, you must go to one of summer festivals held anywhere in Japan.
If you chose
autumn to come, you would be moved by the beauty of autumn leaves. The autumn leaves at temples in Kyoto is truly amazing.
In case of
winter, you can enjoy Snow Festival, called "yuki-matsuri", in Hokkaido. Also, New Year's Eve (oomisoka) and New Year's Day (oshogatsu) are such such special holidays in Japan.