Shinsuke explains how to address people in Japan

I am writing about the social customs in my country. If you visit Japan, you have to learn some manners. When addressing someone, you can use the word San, Kun or Chan after their first name or surname, but it depends the situation, your age or their characters. In a casual situation you can use any of them, but usually you should use Kun for male, Chan for female and San for either of them. In more formal situations you should use only the word San. This is like Mr. and is used for addressing both men and women. However, there are many exceptions and I think they are difficult for foreigners learning Japanese to understand completely. For example, if you use Chan for your male teacher, you must go his room after school. It shouldn’t be also Kun or even San but that is much better than Chan…. You have to use Sensei, which means ‘teacher’. I don’t know why we use such needless and confusing words and I can’t explain that any more. So I think you shouldn’t use them at all whenever you are in Japan because you are not Japanese and they must be kind of you.