When travelling to Japan, there are a few things you should never do in order to avoid offending the local people. One of the most important things to remember is never to blow your nose in public. Blowing your nose in public is considered to be very rude in Japan and is best avoided. If you need to blow your nose, do so in a private place such as your hotel room.
Another important thing to remember is to never touch someone on the head. The head is considered to be the most sacred part of the body in Japanese culture and so touching someone on the head is considered to be very disrespectful. If you need to gesture to someone, do so by waving your hand in front of their face instead.
When entering a Japanese home or business, it is important to take your shoes off before entering. This is because shoes are considered to be dirty and it is thought to be rude to bring them into a clean environment. You will usually find a shoe rack near the entrance of Japanese homes and businesses where you can leave your shoes.
It is also important to avoid eating or drinking in public places such as on the train or in the street. Eating and drinking are considered to be private activities in Japan and so doing them in public is considered to be very rude. If you need to eat or drink, do so in a restaurant or cafe.
Finally, you should never give a Japanese person a gift with four of anything. The number four is considered to be unlucky in Japanese culture as it is pronounced the same as the word for death. So giving a Japanese person a gift with four of anything (four apples, four coins, etc) is considered to be very bad luck.