Japanese dialects
There are several generally similar approaches to classifying Japanese dialects. Misao Tōjō classified mainland Japanese dialects into three groups: Eastern, Western and Kyūshū dialects. Mitsuo Okumura classified Kyushu dialects as a subclass of Western Japanese. These theories are mainly based on grammatical differences between east and west, but Haruhiko Kindaichi classified mainland Japanese into concentric circular three groups: inside (Kansai, Shikoku, etc.), middle (Western Kantō, Chūbu, Chūgoku, etc.) and outside (Eastern Kantō, Tōhoku, Izumo, Kyushu, Hachijō, etc.) based on systems of accent, phoneme and conjugation.