In Japan, the customs are so strict that a simple mistake on a Japanese business trip can cost you not only the deal, but also your dignity. Japan's major religion is Shinto (“the way of the gods”) and is woven into everything the Japanese do:
Language: The majority of the country speaks Japanese. You should use the language of your client in doing business. If you don’t know Japanese, learn phrases like “Hello, my name is,” “Nice to have met you,” “Goodbye,” “Thank you,” “Please,” “Excuse me,” and “I’m sorry.”
Saying “yes” is done with a nod. Saying “no” is done by placing a hand in front of the face and waving it back and forth. In a business situation, simply saying "no" is disrespectful; expressing regret, however, gets the point across and can help you save face.
Appropriate dress: Japanese business professionals are very careful in the way they dress, which is on the conservative side. Men should wear well-pressed dark blue or black suits and ties; businesswomen should also dress conservatively.
You'll encounter many opportunities to remove your shoes on a business trip in Japan, so make sure that your socks or nylons are without holes, and have at least one pair of shoes that are tieless. Scruffy shoes aren’t acceptable.
Greeting rituals: Most Japanese businesspeople shake hands and bow when greeting you. Allow your Japanese colleagues to lead the way. If they shake hands first and then bow, you follow suit. Women normally don’t shake hands, though this rule is changing.
When you bow at a meeting in Japan, the degree is as important as the action. The 45-degree bow, with palms in front of your knees, is offered to only the most senior members. The 30-degree bow, with legs straight and hands at your sides, is most common. Use the informal bow (the quick bowing of only the head and shoulders) before shaking hands if your Japanese counterpart extends his hand.
Business cards: In Japanese, the family name precedes the personal one. Business cards and their presentation are extremely important to the Japanese. Have your business cards translated into Japanese on one side, and change your title if what you do isn’t clear.
Dining and entertaining: In Japan, business entertaining usually occurs after hours and rarely in the home. You’ll be entertained often and many times with little notice. Be a gracious guest and enthusiastic while eating, and show great appreciation afterward.
Giving and receiving gifts: Gift-giving in Japan is deeply rooted in Japanese culture. Always bring gifts for new and old contacts. These gifts should be indicative of your rank with your company; the higher your rank, the higher quality of the gift. Don’t give monetary gifts or gifts displaying company logos, though office accessories such as a good-quality pen are suitable.
Social taboos: Don’t cross your arms when speaking or listening to someone. When dining, never point, gesture, talk with your chopsticks waving in the air, or take food from another person’s plate with your chopsticks. Also, avoid using American slang.