The album was later included in Tatsumi Takayuki's book Philosophy of Progressive Rock (プログレッシヴ・ロックの哲学, Puroguresshivu Rokku no Tetsugaku), which led to the band being classified under the progressive rock genre.
Albummet blev senere inkluderet med Tatsumi Takayukis bog Philosophy of Progressive Rock (プログレッシヴ・ロックの哲学, Philosophy of Progressive Rock), hvilket gjorde at banded blev placeret under genren progressiv rock.