[Troo]

Originally Posted by Kitsuneko

If you receive a business card from someone, don't just stuff it in your pocket, especially your back pocket. It's considered insulting.

Further to this, take the time to examine the card and read it, both sides. Even if it's in Japanese and you cannot read Japanese, take the time to make the examination. Then be very careful to show that you are placing the card somewhere both safe and important - a central compartment in your wallet is ideal, particularly if it has a clear front so that you can see the card without removing it.

Originally Posted by Kitsuneko

Take a bath before jumping into a o-furo or hot spring, and don't wear a swim suit when you do.

There should be a shower area before the bath itself. Shower thoroughly - sit on the stool provided if it's more comfortable to do so. Ensure you are completely clean before moving on to the bath - taking a soap sud in with you is incredibly poor form.

Once in, rest and relax. You are there to soak, not to wash. Do not dip your head below water.

Finally, don't worry about being naked in front of other people. They'll all be naked in front of you, too

Once you're out, wrap yourself in a towel. Don't get the towel wet in the bath.

Originally Posted by Kitsuneko

Don't wear the 'WC' slippers outside the restroom. Yuck. Only Izumi Curtis can get away with this sort of thing.

Heck, she can get away with whatever she likes. I'm not going to argue with her!

Originally Posted by Kitsuneko

Learn the phrase "onegai shimasu"; it's polite and greatly appreciated when we used it. That and "sumimasen" were very very useful.

Yep, it's certainly worth learning a few basic words and phrases before you go. The Japanese are ever so appreciative that you bothered taking the time to learn even a handful of words. If you've any allergies / special requirements I'd really recommend learning an associated phrase or two (e.g. if you're a vegetarian, best find a phrase which communicates this to waiters. If you have a medical condition which could affect you and cause an emergency, learn the phrase which will communicate this to passers-by, etc).

I've found that even out in the depths of Kumamoto you will find signs written in romaji and people who understand a few words of English, so armed with a few words in Japanese you should survive just fine.

Words I take the trouble to learn in the native language of every country I go to include yes, no, please, thank you, excuse me, this / that one, and perhaps the names of a few local food items. For Japan this list would be:

Yes: Hai.
No: Iie (pronounced ee-eh, but saying iie outright is considered a little... blunt. Try to avoid it if possible).
Please: Onegaishimasu, or okudasai. I tend to stick with okudasai, but if you're asking for service of any kind (a taxi ride, etc) use onegaishimasu.
Thank you: Arigato gozaimasu, or domo arigato gozaimasu. In an informal setting "arigato" will do, and in a really informal one "domo" is enough. Be prepared to say this four or five times in a single transaction at a checkout, and make your last one "arigato gozaimashite" instead.
Excuse me: Sumimasen. Sumimasen is, in Japan, the one word you'll need more than any other. It stands in for excuse me, pardon me, I'm sorry, and a whole variety of other requirements. Need to pass in front of someone? Bow slightly and say "sumimasen". Accidentally bumped someone? Sumimasen. Someone accidentally bumped you? Sumimasen. It's brilliant
This one: Kono (e.g. Point and say "Kono wa okudasai". It's childish, but gets the point across)
That one: Sono
That one, over there: Ano

Wikipedia has an excellent few pages on Japanese food. Print them out and take them with you. You can use them to identify menu items by Kanji alone, or to point at and look hopeful at the waitress. Most places have pictures on the menu so that you can point at whatever looks tasty.

A few other phrases:

Do you have an English menu? : Eigo no menyuu wa arimasu ka ("ka" is essentially a verbal question mark, so lift your voice at it as though it were written "ka?").

Where is the nearest toilet? : Ichiban chikai toire wa doku desu ka.

Where is the train station? : Eki wa doku desu ka.

Beyond that I'd suggest picking up a beginner's Japanese book and CD and ramming as much into your head as possible before you go. It's a very structured language with fairly simple rules at the basic level, so nowhere near as intimidating as you might think (they save the indimidation for writing )

Enjoy!