Backpack or rolling suitcase?

I'll be in Japan this summer for 6 weeks. I'll be staying mostly at youth hostels. Do anyone have a recommendation about whether a backpack or small suitcase on wheels would be better under these circumstances?

Whatever works for you. I have sue both while traveling in Japan. I find it much easier to use a rolling suitcase over a back pack. And the type with the 4 wheels on the bottom is are easier to manuver than the 2 wheel type. But even with the suitcase, I bring a backpack to use on day trips.

I usually use a backpack when travelling in other parts of Asia, but always a suitcase in Japan. It is extremely hot and humid in summer, so better to wheel your luggage than have to carry the full weight. There are a lot more elevators and escalators in the stations now so you will hardly ever have to haul it up the stairs.

I would suggest bringing as little as possible. After traveling to Vietnam and Japan with a suitcase, I will never travel with a suitcase again. I'd bring just two or three other pairs of clothes, and do laundry every three or so days. If you are going to be hopping around from city to city, but going directly to a hostel to drop your things off, then a small (small as possible, like backpack size) rolling suitcase would be fine. But if you will be walking a lot between hostels, I'd bring a backpack. The key really is bringing as little as possible.

Either is fine really since it seems like you're going to be traveling around the country.

Just remember that if you're on a packed local train, take off your backpack and keep it on the floor. Some people get really peeved on packed trains when folks are still carrying their backpack on their back and takes away space from other passengers.

Other than that though, I can't really think of other differences. Just keep it small enough so you can easily carry it around on trains and overhead racks on trains.

When I travel in Japan I use a small wheeled suitcase. Most important to me is that its small enough to fit in a regular sized locker: approx 35cm x 43cm x 57cm
(13in x 16in x 22in). Also, I find that my 4 wheeled hardcase is easier to carry and maneuver in the train stations than my 2 wheeled one. I also carry a messenger bag or daypack as well.

Or you could always get a suitcase with zip away backpack straps like this:

http://www.eaglecreek.com/bags_luggage/wheeled_luggage/...

So, I plan on doing a bit of backpacking through Japan, staying at one hotel along the way and mostly hostels and maybe a capsule hotel for the rest. Now, I know the typical lockers located in stations, capsule hotels, etc are about 35cm x 43cm x 57cm, so what kind of backpack or luggage could I get that would be insured to fit inside?

Now, I know the typical lockers located in stations, capsule hotels, etc are about 35cm x 43cm x 57cm, so what kind of backpack or luggage could I get that would be insured to fit inside?
Take these measurements to a luggage store and see what they have..squashable soft is better than hard case