Well this is from
http://www.cnfj.navy.mil/duty.html-Japan has an area slightly smaller than California and has a population of 126 million, making this country the fifth most populous in the world.
-English-speaking policemen wear a red armband.
-Shintoism, Buddhism and Christianity are the main religions practiced in Japan.
-The three largest corporations in Japan are 1) Mitsubishi, 2) Sumitomo, and 3) Itoh.
-Japan's unemployment is about 3 percent.
-Tradition says that the eldest son and his wife have the major responsibility for caring for his parents.
-Most Japanese have studied English in school, but their studies were geared toward passing exams, not holding conversations. As a result, many hesitate to speak English, but may understand more than most Americans give them credit for. They may therefore be offended if spoken to in broken English.
-There are approximately 250 colleges in Japan, with 80% of them located in the Tokyo area.
-Very few Japanese appreciate being called mama-san or papa-san, so forget what you've seen in the movies.
-The Japanese consider it inappropriate to show affection in public.
-The average female marries at age 24 and the average male at age 27.
-In most homes and some restaurants, you'll have to remove your shoes before entering.
-Green tea is the national drink of Japan.
-Japanese drive on the left side of the road.
-Water is safe to drink, except in the most remote areas of the country.
-Hashi (chopsticks) are the normal eating utensils. Using them is easier than you might think.
-Some restaurants and nightclubs might be closed to foreigners; it's best to check before you enter.
-It's not unusual to hear Japanese slurp as they eat ramen or other noodle dishes; but, it is impolite to smack your lips, speak with your mouth full, or use a toothpick in public.
-Many Japanese restaurants have plastic or wax food on display in windows or cases to show passersby the types of food served.
-Bar snacks are not usually free.
-Japan is the largest importer of food in the world.
-Tipping is not an accepted practice in bars, restaurants, taxis, etc.
-Travelers checks and credit cards are not accepted in many restaurants.
-Bargaining in Japan is not generally accepted. The price listed is the price you pay.
-Japanese do not use personal checking accounts, so personal checks are not acceptable payment outside of U.S. facilities. U.S. dollars must be exchanged on base or in a Japanese bank prior to making purchases off-base.
-Stores are usually closed Jan. 1-3 to celebrate the New Year.
-Sumo is the national sport of Japan, despite the popularity of baseball. Sumo wrestlers are often 6 feet tall and weigh more than 300 pounds.
-If you visit a public hot bath, remember the tub is for relaxing, not cleaning. Shower before entering the tub.
Those are some good things to know I think. ^^