14

Background
The song was first uploaded on December 26th 2009 as one of the songs/videos made for the Kagamines' second anniversary. Nata-P mentioned on his description saying "forever 14, I wanted to make a feeling that it's sung by someone of the age of 14." The number 14 is chosen because it's Len and Rin's "age".

14 is one of the tracks chosen to be in one of KarenT's "Kagamine Anniversary 2009" albums. This song is released as a singles album that consists of three tracks; the original, a Rin version, and the instrumental off vocal as well.

It tells a story of how Len wonders the meaning of birth, the meaning to why they start to change from their birth to the point where they're 14. Songs were made as "you" (presumably Rin who was also in the video) were born as so did he. In the end he sang a song, "your song" so that Rin won't be lost and forget the wonderful memories. He hoped that she'll find that "one thing" she was looking for.