Play word 皆婚社会 皆婚社会 かいこんしゃかい marriage-oriented society (in which most people are married, usu. at a young age)
Play word 格差婚 格差婚 かくさこん marriage in which one partner (esp. the wife) has a significantly higher income or social status
Play word 貴賤結婚 貴賤結婚 きせんけっこん morganatic marriage (marriage of a noble and a commoner that disallows the passage of title, possessions, etc.)