Vitamins Vitamin supplements are expensive, if you are used to taking them, bring a supply. Even if you don't, it's not a bad idea to bring some. Some JETs I know take iron supplements. Cosmetics Cosmetics are very expensive here, so go ahead and bring a little extra if you can. If you have favorites, bring some extra.
Toiletries are available in Japan, but they are pricy.
You'll be glad you did. The strengths of this book are good maps, place names in Japanese characters, excellent introductory essays, and most importantly, the book is laid out by the train routes, which is the way most people get around anyway. It's difficult to know how many gifts to bring, or who to give them to. Guidance before you get here is best received from your predecessor. Any gift that reflects your own culture or hometown will surely be appreciated.