Under the common understanding of the importance of cooperation of academics, judges and attorneys, we have analaysed the determination of parent-child relationship, Adult Guardianship and Division of Inherited property. As to the determination of parent-child relationship, the point is the range of effect of the agreement of parties. In Adult Guardianship, the problems of the direction of family court, Convention on the Rights of Persons with Disabilities, and mandat post mortem should be discussed. In the practice of Division of Inherited property, the problem of inheritance of cryptocurrency is important.