The small group of Hachijō or Hachijōjima dialects are the most divergent form of Japanese. They are spoken on the southern Izu Islands south of Tokyo, Hachijō Island and the smaller Aogashima, as well as on the Daitō Islands of Okinawa Prefecture, which were settled from Hachijō in the Meiji period. Based on the criterion of mutual intelligibility, Hachijō may be considered a distinct Japonic language.