In Japan, there are certain rules which if you don't know, may offend the Japanese citizens, even if you don't realize it. For example, if you go to someone's house, or maybe even a restaurant, you have to slurp your food while you eat. If you don't they'll think you are not enjoying it. You must also always take off your shoes before you enter someone's house, and change into the house slippers. However, if you go into the bathroom, you need a separate pair of slippers as well. Is it also always a great way to show respect by giving your host a gift when you are invited to someone's house.
There are enormous amounts of festivals for people to enjoy in Japan. For more detail, go to this website; http://www.japan-guide.com/e/e2063.html
Japanese swords, otherwise know as "Nihonto" has been internationally known for its sharpness and beauty since the Japanese feudal era. The sword was once the distinguishing mark of the samurai. Since swords are a type of dangerous weapon, a permit is required to own one in Japan today.