In small or medium scaled powerful families in the Kinai area and among local powerful families, ujigami was believed to be an extension of the conventional belief, however, in the late Heian period when the shoen-koryo system (a manor and public territory system) was established and the handing down of territories and properties between fathers and children became common, the conventional manner of ujigami worship in each clan collapsed and, when territory management by 'family' as a unit gradually became common, chien-gami god (the locally connected god) of each territory or ubutsuchi-gami god (soil producing god) of one's home town was worshipped as ujigami and, as this confusion advanced, new ujigami were established in various places.
畿内の中小豪族や地方豪族では、旧来の延長上の氏神信仰が行われてきたが、平安時代後期に荘園公領制が成立して、父子間の所領・財産継承が行われるようになると、各氏族の氏神崇拝の従来のあり方が崩れていき、次第に「家」単位での所領経営が行われるようになるとそれぞれの所領の地縁神もしくは出身地の産土神を氏神とするようになり、その混同が進行するとともに各地に新たな氏社が成立するようになった。