The true "sigh motif" is a semitone, but in this piece, I used it as a fifth. The fifth is a very important interval for piano technique. Practice so that even with small hands, you can firmly grasp the keys. Furthermore, if you focus on adding expression not only to the notes but also to the rests, you might achieve the feeling of a "sigh." I hope that this piece allows you to experience a little bit of a mature feeling.