What is "Kayokyoku"?

Kayokyoku is a general term for Japanese popular music that was popular from the 1920s to the 1990s. We are convinced that kayokyoku, especially those popular in the 1970s and 1980s, have an appeal that has not faded away in the modern age.
Even though the City Pop movement has brought Japanese music to the attention of the world, we know that there is still a lot of great Kayokyoku that has not yet received the attention it deserves, and we want to share it with everyone in the world.