Language is often described as a mirror reflecting the contemporary world, and since Meiji era, there have been many twists and turns in Japanese language policy for the last 130 years throughout the modern history. Especially the relationship between the dialects and the standard language, which has repeatedly experienced confrontations and conflicts, has been a major issue of Japanese language policy. Before the middle of Meiji era in the late 19th century, dialects were the only language used in daily lives of the ordinary people. Also, the ordinary people did not feel comfortable with the standard language. After the middle of Meiji era, dialects became the target to exterminate, as the government in the mood of the strong nationalism started promoting the standard language. After the defeat of World WarⅡ in the middle of the 20th century, dialects were losing their grounds as the common language has rapidly spread as the awareness of citizenship grew. Also, the dialect used to transmit ideas has become one of the linguistic choices based on the styles. This article is an overview of Japanese language policy in Japan, especially on the relationship between Japanese dialects and standard language and the advent of the common language.