The Tōkai–Tōsan dialect (東海東山方言 Tōkai–Tōsan hōgen) is a group of the transitional Japanese dialects spoken in the southern and eastern Chūbu region. The dialects spoken in the northwest Chubu region are classified as the Hokuriku dialect of Western Japanese. The Tokai–Tosan dialect has three sub-groups: Gifu–Aichi, Echigo, and Nagano–Yamanashi–Shizuoka. These are transitional between Western and Eastern Japanese; which branch of the family they fall in depends on which isoglosses are taken as definitive. (See Eastern and Western Japanese for details.)
The Nagano–Yamanashi–Shizuoka a.k.a. Na-Ya-Shi dialects are spoken in Nagano Prefecture, Yamanashi Prefecture and Shizuoka Prefecture. It is characterized by a presumptive suffix -zura or -ra.
The Echigo dialect is spoken in mainly Niigata Prefecture, formerly known as Echigo Province except north of the Agano River.
The Gifu–Aichi a.k.a. Gi–A dialects are spoken in Gifu Prefecture and Aichi Prefecture. They share many grammar features with Western Japanese.
Mountain village dialects that retain fragments of Eastern Old Japanese.