The song was first uploaded on February 5, 2009; making it DATEKEN's 4th work. It's been covered by various utaite, and in various languages (Japanese, Chinese, Korean, English covers). To date, the video has reached over 400,000 views. The song is featured in an EXIT TUNES compilation Vocalogenesis.
The song tells of two people (the song is separated to two parts; Rin's part and Len's part, though both are present in the chorus / reff) reminiscing of the past and how they should sing the song of the present; and not looking back to the past.
DATEKEN usually gives a description on what his "made up language" (common in folk) means (for example see Jutenija), though in this song, "al a re ya" has no definite meaning and is only a sound he once made when he woke up.
Many had mistaken the song to a Japanese folk song. However, it is best described as a Chinese folk song with Japanese lyrics. Due to Len's use of a Đàn Nguyệt, it may also be considered a Vietnamese folk song.
DATEKEN stated the "meaning" to "al a re la ye" is the sound he made when he woke up from bed. Essentially, it has no definite meaning.
This is DATEKEN's first song to have achieved the title "Legendary Kagamine Master" in Nico Nico Douga
This is also his first song to have reached Nico Hall of Fame (exceeding over 100,000 views)
The instrument Len is playing is a Đàn nguyệt, while Rin plays the Erhu.