> Nowadays, legal adoption of this kind is paired up with an arranged marriage — known as "omiai" — of a daughter, meaning the adopted son becomes son and son-i

> Nowadays, legal adoption of this kind is paired up with an arranged marriage — known as "omiai" — of a daughter, meaning the adopted son becomes son and son-in-law at the same time because he changes his name to the wife's family name ("mukoyoshi"). So, daughter marries son-in-law, who is "adopted" into the family and carries on the family name.