The twenty-two shrines. An elite grouping of shrines (sixteen to begin with) in the Kyoto-Ise-Nara area which from the mid-Heian period acquired a high and separate status, differentiated from shrines elsewhere in the country. They were grouped into three divisions; the 'upper seven' shrines (Ise, Iwashimizu, both Kamo shrines, Matsuno, Hirano, Inari and Kasuga), the 'middle seven' shrines (Oharano, Omiwa, Isonokami, Oyamato, Hirose, Tatsuta, Sumiyoshi) and the 'eight lower' shrines (Hie, Umenomiya, Yoshida, Hirota, Gion, Kitano, Niukawakami and Kifune).
See Ichi-no-miya.
A Popular Dictionary of Shinto. Brian Bocking.