陰陽座 (Onmyouza, stylized as Onmyo-za) is a heavy metal band from Japan who released their first commercial album in 1999. They play quite orthodox style heavy metal music mixed with Japanese folk themes and pop music elements. Since their debut, they have appeared in traditional clothing characteristic of Japan's Heian period. Their songs mainly deal with oni, yokai, Japanese dragons, etc, but some songs have a more concrete theme and inspiration.