text: The Japanese family system ( ) was also regulated by Confucian codes of conduct and had an influence on the establishment of the senpai–kōhai relation. In this family system the father, as male head, had absolute power over the family and the eldest son inherited the family property. The father had power because he was the one to receive an education and was seen to have superior ethical knowledge. Since reverence for superiors was considered a virtue in Japanese society, the wife and children had to obey it. In addition to the hereditary system, only the eldest son could receive his father's possessions, and neither the eldest daughter nor the younger children received anything from him.
  The last factor influencing the senpai–kōhai system was the Civil Code of 1898, which strengthened the rules of privilege of seniority and reinforced the traditional family system, giving clear definitions of hierarchical values within the family. This was called koshusei (, "family-head system"), in which the head of the household had the right to command his family and the eldest son inherited that position. These statutes were abolished in 1947, after the surrender of Japan at the end of World War II. These ideals nevertheless remained during the following years as a psychological influence in Japanese society.
  Terminology
  The seniority rules are reflected in various grammatical rules in the Japanese language. A person who speaks respectfully to a superior uses honorific language ( ), which is divided into three categories: