Along with 新曲2, 新曲6 never received an official title and was never properly released. There are also no known performances of this song, it's only known because of a mention in a FOOL'S MATE interview in April 1998. The interviewer asks Kaoru what became of this song; Kaoru explains that he felt he had to change the title as the song itself had changed too much. It's unknown which title this song received, but it was wrongly assumed to be 刹那, which was renamed to Unknown…Despair…a Lost in early 1998. However, in June 2023, Shinya took to Twitter to clarify that 新曲6 was in fact not the working title for 刹那 and instead a completely different song.