The first pressing of the single included a bonus CD-ROM featuring a special video message from Ueto, as well as a program allowing fans to receive emails from her for a limited period.

The track is a midtempo ballad and, like "Pureness," it was written, composed, arranged and produced by T2ya.

Due to the hectic filming schedule at the time, Ueto did not do any televised promotion for the single.

[2] The video shoot was squeezed in an opening in the filming schedule when the crew for Azumi were moving locations from Kyoto to Hiroshima, giving Ueto just enough time to film the video and get back to set the next day.

[2] "Kizuna" entered the daily Oricon Singles Chart at number 3.