David Spafford examines the relationship between warrior houses and their names in fifteenth- and sixteenth-century Japan. Widespread reliance on adoption of heirs and the less common revivals of extinct houses reveal how late medieval warriors framed the membership and boundaries of the house ( ie ). Together and separately, adoptions and revivals force us to reckon with the malleable nature of warrior houses—which included both kin and non-kin—and their essentially political character. They force us to think through the several dimensions of the ie as an analytical framework: heraldic group, house/lineage, household. The decisions of individuals and individual lineages about naming, affiliation, and identity demonstrate both that a house’s surname served to symbolize familial continuity and that the openly constructed nature of the house-as-multigenerational-named-entity allowed strategic use of marriage and adoption for family survival through the long age of civil strife.