Onna Koshu (Ffemale Head of a Family) (女戸主)
Onna Koshu was defined as a female head of a family according to the Old Civil Codes of Japan.
In principle, a head of a family was a man, but a woman was also allowed to succeed the position of family head.
A female head of a family was possible because a female illegitimate child or a female child born outside of marriage could establish a family.
When a female head of a family wanted to retire, only a simple acceptance of the succession by a successor with full ability, regardless of age, was necessary.
For a female head of a family to join another family by marriage, she had to retire or abolish the family.
If she was the founder of a family, she was free to abolish her family.
Even in the case which was not generally acceptable, she could retire or abolish the family in order to get married, only if she obtained permission specially from the court.
When a female head of a family wanted to marry staying as the head of her family, her husband married into her family which was called Nyufu marriage.
Even in the case of Nyufu marriage, if a female head of a family did not wish to reserve the position, her husband of course replaced the position.
If she wished to reserve the position, she would not lose the position of the family head even after marriage and kept the right to use and profit from her husband's property, on the other hand, she had to pay expenses including cost of shared living and education fee for their children.