For the method of water and air purification, see Carbon filtering. Charcoal Filter (チャコールフィルター), also known as Charcofil or Chakofiru (チャコフィル) to their fans, is a Japanese male rock band. Its members are Takahiro Konagawa, Yuzo Otsuka, Yuki Yasui, and Shintaro Takano. They met each other and formed Charcoal Filter in their high school days.