[gaijzilla]

Japan is a largely cash based society. Barely anyone uses a credit card and there's no such thing as personal checks.
Rather than using a credit card, people carry large sums of cash. It's not uncommon for someone to be carrying the yen equivalent of thousands of dollars. That's what I had to do before I got a bank account. You will probably have to pay for very major things, like an apartment, in cash. Rather than using personal checks, you sign standardized agreements that allow people to make direct withdrawls (pretty much the same thing but not nearly as handy).

One of the most popular banks in Japan is the post office. That's what I use. However, making transfers to/from overseas with a postal account is probably not easy. I haven't gotten the nerve to try yet.