While the most likely opinion has it that powerful regional clans offered their daughters as a kind of hostage to show their subjugation to the emperor, there is another opinion based on the official document from Daijokan in 917, which forbade Izumo no Kuninomiyatsuko to have a mistress under the pretext of 'Jingu Uneme' except for one Uneme for shinto religious services as required, that Uneme was supposedly a system established in the process of integration of regional religious services by the Imperial family, and that Uneme was identified with the mistress in the religious service, implying the conduct of making Uneme pregnant as mentioned later.
一種の人質であり、豪族が服属したことを示したものと考える説が有力だが、延喜17年（917年）の太政官符に、出雲国造が「神宮采女」と称して妾を蓄えることを禁止しつつも神道祭祀に必要な場合には1名に限り認める内容のものがあることを根拠に、地方の祭祀を天皇家が吸収統合していく過程で成立した制度で、祭祀においては妾と同一視され後述のとおり子供が出来る行為を伴ったと推測した説もある。