Kotofu is a family register of Imperial family which is a base to decide the order of succession to the Imperial Throne and to notarize the lineage relation (family relation) of Imperial family.
皇統譜は、皇室の身分関係（家族関係）を公証し、皇位継承の順序を定める基礎となる、皇室の戸籍にあたる。