This is back number singing to someone younger, and it is quietly one of their most humble songs. The narrator admits right away that he never really grew up: "大人になれなかった" [I couldn't become an adult], and he keeps that secret to himself. He was given so many good things, "抱えきれないくらいに" [more than I could hold in my arms], and he still feels like he has nothing to show for it.
The heart of the song is the picture of a kid tracing clouds with a fingertip, "僕にはもう見えないものを" [things I can no longer see]. He would love to say something wise, but he thinks he would never find the words. Then the self-doubt gets almost funny in its honesty: maybe all he has to pass on is a rainbow painted on a "張りぼて" (a papier-mache prop, basically something fake and flimsy) or a baton "手垢にまみれた" [covered in fingermarks]. The baton is the relay image: one generation handing something to the next.
The repeated "誰の人生だ" [whose life is this?] hits hard after the image of a closed picture book. His answer is lovely: he wants their future to stay "真白なまま" [pure white, untouched] so that they can paint it themselves. And the ending is small on purpose. If one day they want to make someone happy, and he can just smile and nod, he thinks "それでもうじゅうぶん" [that would already be enough]. A dad song, or an older-brother song, with zero lecturing in it.
back number is a Japanese rock trio formed in Gunma Prefecture in 2004 by singer and guitarist Iyori Shimizu, with Kazuya Kojima on bass and Hisashi Kurihara on drums.
The band signed to Universal Sigma and made its major-label debut in April 2011 with the single "Hanabira".