This paper seeks to clarify the disincentives in “inheritance-via-the mother, ” the case where mother inherits a part of a father's inheritance in order to secure her remaining life. Based on study of a number of cases, it appears that inheritance-via-the mother is often obstructed by a child with whom she lives. An important finding of this study is that we must think about this matter by dividing it into two stages; a mother's attitude toward her inheritance and her environment surrounding her inheritance.