Kesen is spoken in the Kesen district, Harutsugu Yamaura developed a writing system for Kesen but has no known dialects.
Kesen dialect (, Kesen hogen) or Kesen (, Kesengo, Kesengo) is a Japanese dialect spoken in Kesen County, Iwate Prefecture, Japan. Yamaura also created an orthography for Kesen using two writing systems, the first based on the Latin script, and the second on the Japanese writing system. Yamaura has forwarded the theory Kesen should not be considered a Japanese dialect, but an independent language in its own right with an Ainu substrate, a theory that is controversial. Kesen dialect has been described as a variety of the Tohoku dialect. 
