There are a number of unwritten rules in daily life in Japan, which everybody observes, but nobody talks about, and which don't exist in Europe or USA. It's your choice in a way, but you'll make more friends and definitely be more successful in business if you observe these little rules.

• Take enough ("enough" often means a couple of hundred) professionally prepared "meishi" ("meishi" = business cards). For Japanese people (as else where in Asia-Pacific) exchanging "meishi" are like shaking hands. It is very awkward not to exchange "meishi" when you first meet. So make sure you have enough. Not to have "meishi" has the meaning of being unemployed.
• Impress with facts and achievements, or the fame and power and size of your corporation. Bring documentation of your company in Japanese language.
• Be on time and well prepared for meetings.
• There is a sophisticated protocol how seating is arranged at meetings, at dinners or in cars etc. The seating protocol depends on seniority, guest-host relationship, the position of the door, decorations in the room, etc. If you are arranging important meetings or dinners at high level, it will impress if you follow these seating customs. Most foreigners who have not worked a long time in Japan will need advice from Japanese professionals to select the correct seating order. At dinners there are also customs about filling glasses etc.
• There are a number of unwritten rules in daily life in Japan, which everybody observes, but nobody talks about, and which don't exist in Europe or USA. For example: no eating and drinking and no baby's perambulators (except folded up) on short-distance commuter trains. It's your choice in a way, but you'll make more friends if you observe these little rules.