The custom of trance mediumship and spirit conjuring ceremony of the Vietnamese people ; ; On December 1, 2016, the United Nations Educational, Scientific and Cultural Organization (UNESCO) recognized "The practice of worshipping the Mother of the Three Palaces of the Vietnamese people as a representative intangible cultural heritage of humanity". in the practice of worshipping Mother Tam Phu, the ritual of trance mediumship is the basic factor, the top core factor that needs to be studied and learned about the essence.