Ai no Kisetsu

"Ai no Kisetsu (愛の季節)" is the ninth single by Japanese singer Angela Aki and was released on September 16, 2009, one year after her previous single's release. The single contains the song "It's So Hard to Say Goodbye to Yesterday", which is a cover of song by American singer G. C. Cameron by the same title. "Ai no Kisetsu" was used as a theme song for NHK drama, Tsubasa.