from official site
"This is an unknown song that was recorded for the third album Duty. It was born from ayu's desire at the time to "create a song to commemorate a celebration, like a wedding."
The subtitle 〜eternal tie ver.〜 also suggests this feeling. I invite listeners to read the lyrics of this track out loud, as I remember how impressed I was by their completeness, especially given that it was only her third album. Although there was talk of doing a retake, we found that the original take was important as something that could only have been created at that particular time in ayu's career. Thus, we recorded it with only some remastering."