The first thing you'll want to do when you're packing is select the smallest bag you can get away with and pack as lightly as you can. Storage space is limited on Japan's trains, including the Shinkansen bullet train, business hotels sometimes lack closets, and there are multitudes of stairs and overhead and underground passageways to navigate in virtually every train station in the country.
The most important item is a good pair of walking shoes, well broken in. You will probably be walking much more than you do at home. Keep in mind, too, that because you have to remove your shoes to enter Japanese homes, inns, shrines, and temples, you should bring a pair that's easy to slip on and off. And, because you may be walking around in stocking feet, save yourself embarrassment by packing socks and hose without holes.
As for clothes, you'll need a coat in winter and very light clothing for the hot and humid summer months. Jackets are necessary for spring and autumn; I've seen it snow in March in Tokyo, and even May can be quite crisp. Japan's top French restaurants often require jackets and ties for men. Although the older generation considers it inappropriate for women to wear dresses without hose or tops without sleeves, I've noticed that the younger generation ignores this, especially in resort areas. Jeans and Capri pants are okay for casual dining and sightseeing, but shorts are uncommon in Japan outside hiking and sports areas, the exception being children and teenagers.
Virtually all hotels and Japanese-style inns -- save youth hostels and some budget-priced inns -- provide towels, soap, washcloths, toothbrushes, toothpaste, shampoo, a cotton kimono (called a yukata and not a giveaway), and usually razors. If you run out of something, you'll have no problem finding it in Japan. Most hotels and inns also provide a thermos of hot water or a water heater as well as some tea bags. Free coffee is rare, so if you're a coffee addict, you can save money by buying instant coffee and drinking your morning cup in your hotel room. Hair dryers are a standard feature in virtually all rooms with private bathrooms, including business hotels. Because the sun rises early in summer (as early as 4am), you might want to include a pair of eyeshades.
Also carry a supply of pocket tissues, which you can pick up at newspaper stands near and in train stations, because some public restrooms in rural areas might lack toilet paper. It's also a good idea to carry change for local buses (faster than trying to change ¥1,000 notes), a folding umbrella, and a compass for getting your bearings and following directions using local maps. Finally, pack small, inexpensive gifts from home that can be given to those who show unexpected kindness, including candy, postcards, and hometown souvenirs.
Help with Heavy Bags -- If your bag becomes a burden but you don't want to mail items home, an alternative is to send a bag onward to your next or last stop by takkyu-bin, available at larger hotels, train stations, and convenience stores. Bags reach most destinations in 1 or 2 nights, with the delivery cost of an average-size bag weighing 10 kilograms (22 lb.) ¥1,400 ($12/£6). I love this amazingly efficient service -- it's a lifesaver!
