A kannagi represents the act of communicating with a yorishiro of a kami, or a possession of a kami, or a person who serves in that role.
Kumagusu Minakata, in his book Ichiko ni kansuru koto, refers to miko serving shrines as kannagi, and to wandering miko as miko.
Depending on the shrine, the word "kannagi" is used to refer to a miko who serves the shrine, and the word miko is used to refer to a wandering miko. (Ōmiwa Shrine), Waka (Shiogama Shrine), Tamayorihime, Osame (Katori Shrine), Osome (Kibitsu Shrine), Itsukiko (Matsuo Shrine) Suwa-taisha, Kibitsu Shrine,
Kunio Yanagita says that these two types of maidens were originally the same person, but were later separated, because there are other names for wandering miko, such as Oichi of Suwa Shrine, Sou-no-ichi of Atsuta Shrine, and Waka of Shiogama Shrine.[1]