Japanese dialects

Japanese dialects (日本の方言, "Nihon no hōgen") are the dialects of the Japanese language. There are four dialect groups in mainland Japan: Hachijō, Eastern (including Tokyo), Western (including Kyoto) and Kyushu.
The Ryukyuan languages of Okinawa Prefecture (and parts of Kagoshima Prefecture) are not dialects of Japanese and a Japanese speaker wouldn't understand them.