Japanese dialect

Japanese
Geographic distribution	Japan
Linguistic classification	Japonic Japanese
Subdivisions	Hachijō Eastern Japanese Western Japanese Kyūshū
Glottolog	nucl1643
Map of Japanese dialects (north of the heavy grey line)

The dialects of the Japanese language fall into two primary clades, Eastern (including Tokyo) and Western (including Kyoto), with the dialects of Kyushu and Hachijō Island often distinguished as additional branches, the latter perhaps the most divergent of all. The Ryukyuan languages of Okinawa Prefecture and the southern islands of Kagoshima Prefecture form a separate branch of the Japonic family, and are not Japanese dialects, although they are sometimes referred to as such.

Regional variants of Japanese have been confirmed since the Old Japanese era. Man'yōshū, the oldest existing collection of Japanese poetry, includes poems written in dialects of the capital (Nara) and eastern Japan, but other dialects were not recorded. The recorded features of eastern dialects were rarely inherited by modern dialects, except for a few language islands such as Hachijo Island. In the Early Middle Japanese era, there were only vague records such as "rural dialects are crude". However, since the Late Middle Japanese era, features of regional dialects had been recorded in some books, for example Arte da Lingoa de Iapam, and the recorded features were fairly similar to modern dialects. The variety of Japanese dialects developed markedly during the Early Modern Japanese era (Edo period) because many feudal lords restricted the movement of people to and from other fiefs. Some isoglosses agree with old borders of han, especially in Tohoku and Kyushu. From the Nara period to the Edo period, the dialect of Kinai (now central Kansai) had been the de facto standard form of Japanese, and the dialect of Edo (now Tokyo) took over in the late Edo period.