龜田誠治
, also known as "Charcofil" or 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. After graduation from high school, they came out with the song "I start again" in 1999. They are known for creating the song "Tightrope", used as the ending theme of the anime series "Gensōmaden Saiyūki", back in 2000. From 2002 to 2004 they were produced by Seiji Kameda. They disbanded in 2007.