To commemorate the "Asuka Saito Graduation Concert" held from May 17th to May 18th, the full-length music video of "Hard to say" in which Asuka Saito participates have been released. "Hard to say" is included in Nogizaka46's first best album "Time flies", and in addition to the Under members at the time, it is a song in which all members who were affiliated with the group at the time and had experience with Under in the past participated. The music video for "Hard to say" is based on the theme of "remembering one's past self" and is set in locations that each member has fond memories of, both new and old, such as filming locations for music videos of past Under songs and locations where Under live performances were held.