A typical koseki has one page for the household's parents and their first two children: additional children are recorded on additional pages. Any changes to this information have to be sealed by an official registrar.

The following items are recorded in the koseki. (Law of Family Register, (戸籍法), article 13.)

family name and given name
date of birth
date of records and causes (marriage, death, adoption, etc.)
names of the father and the mother and the relation to them
if adopted, names of the adoptive father and mother
if married, whether the person is a husband or a wife
if transferred from another koseki, the former koseki
registered residence honseki chi
History[edit]