Enka is a traditional Japanese music. The style of Enka is a ballad about nostalgia and sadness. It was very popular music before and during World War II. Nowadays, Enka is popular among only the elders.
The music of modern Enka is a combination between 2 kinds of music. The first kind is traditional Japanese music during Meiji period and Taisho period. Another one, which is more popular, is J-POP and American country style music.