Professor Solomon told us about his free e-book "Japan in a Nutshell." I had fun reading parts of it, like this: what *not* to do in Japan:
Don't ask for a substitute beverage at the Tea Ceremony
You may NOT request iced tea, decaf, coffee, diet soda, mineral water, or anything else! Tradition demands that each guest be served the same thing: green tea that has been prepared - in the ancient manner - from a powder. Accept this tradition. The tea hut is not a snack bar.
Don't do any of the following with chopsticks
1) spear food with a single chopstick
2) leave chopsticks sticking upright in a bowl of rice (this is done only when offering rice to the spirits of the dead)
3) lay them directly on the table (instead, take the package they came in and fold it into a makeshift rest)
4) hold them behind someone's head to simulate horns (such antics are acceptable only if a large quantity of sake has been drunk by all)
Don't pour soy sauce on your rice
The illustrator of this book did so, and was gently chided by his host. It was explained to him that a bowlful of rice is complete - is noble in its unadorned state.
Don't use soap in a public bath
A major gaffe.
Don't mistake lockers at the train station for a capsule hotel
These coin-operated receptacles are for stowing away your luggage - not for spending the night.
Link - Thanks Professor Solomon!