Packing List
Use a small, compact suitcase. Avoid anything large and bulky. My advice is this: pack all the clothes you will need for one week. Then if you need more, in the event you go clubbing, etc. go shopping for some new clothes with your Japanese friends. As a Westerner you'll probably take a size Large. Also get something loose and stretchy, even oversize with short or 3/4 sleeves. The full length sleeves on a typical Japanese jacket or dress may be too short for you.
I will advise that although many young people in Japan are trendy and radical in their styles, most Japanese are conservative dressers. If you go visiting, especially to meet older people, clothing similar to 'dress casual' will go over much better than 'dress down' styles of clothing. If you go up north to Hokkaido, there could be snow as late as March or April. It's quite cold there, sometimes the wind stings. Bring a muffler to wrap around your face and a good sturdy pair of boots like Timberlands. Bring lip balm and lotion for dry skin. The winds and cold in Sapporo can be harsh.


Japanese castle, Odori Park
Yosokoi Festival 2005 Me with dancers and friend