The Japanese commonly address each other by their last name. Close friends and children are usually addressed by their first name. The use of titles is very common and each title represents a different social meaning. The title is commonly added to the last name – Koichi Tanaka would be referred to as Tanaka-san, for example (though in Japan the first name actually follows the family name, so Koichi (first name) Tanaka (family/sure name) would be called Tanaka Koichi). San is used in most situations and is the most neutral title. In the more formal situations, san may not be polite enough. Sama is a more polite form of san, commonly used in formal situations and letters. Kun is an informal title used for younger boys and girls and that are younger than you. Chan is an informal title used for young children and very close friends or family members. Sensei is a title used for teachers, doctors and other people with a higher education and from whom you receive a service or instructions. Dono/tan/han are other suffices but uncommon in modern society.