業 / 蒼い月 (Karuma / Aoi Tsuki) is Dir En Grey's first and only demo tape, as well as their first musical output in general.
The single-sided cassette was recorded at M4 Studios in Osaka, Japan, approximately in March 1997. It was then sent to various radio stations and people in the music industry and as such, it can be heard during an interview on May 30, 1997, when Kaoru appeared on the radio show PowerRockRevolution. You can listen to the interview here.
Being the first musical output by the band, this demo tape is highly sought after and was sold for prices as high as ¥48,600.
The two songs were used as background music on 1997.6.14 目黒鹿鳴館 and 1997.6.27 COWBOY WORLD and later officially released on 「楓」~if trans…~ (1997) and MISSA (1997), respectively. You can listen to the full tape here.