"Kuon no Kawa" is the ninth Japanese single released by alan.

Slightly different end roll versions of the songs are also included in the movie's original soundtracks, composed by Iwashiro Taro.

On the sixth day of release, it suddenly jumped from #10 to #1 on the Oricon Singles Chart, her first #1 daily.

This made her the first Chinese singer to reach #1 on the Oricon daily chart.

It is also the first single by alan to pass the 30,000 units sold mark on the Oricon, beating "Red Cliff: Shin-Sen" by more than twice.