Double marriage is a form of matrimony that involves two couples entering into a legally binding relationship with each other. It has become increasingly popular in Japan as an alternative to traditional marriage models, but is not officially recognized by the Japanese government and carries no legal rights or benefits. There are many challenges associated with double marriages, such as property ownership, financial obligations, parenting responsibilities, and emotional support. Public opinion towards double marriages is mixed due to its unconventional nature and lack of legal recognition. Couples should be aware of the potential implications should either partner decide to end the union unilaterally without consent from both parties involved.