Because there is a principle that a husband and a wife must be on the same household register, a wife of a head of a branch family and also a wife of a lineal descendant must be registered on the new household register with their husband.
ただし夫婦同籍の原則があるため、分家者の妻と、直系卑属が新たな家に入るときの妻はかならず共に移動することになる。