The single was announced on January 15, 2021 during STU48's first Nippon Budokan concert, followed by the first live performance of the title song.[1] The song uses quadruple meter except for the chorus, during which it switches to triple meter.[2] The music video is the first one from STU48 to heavily utilize computer graphics along with outdoor scenes filmed on Kamikamagari Island in Kure, Hiroshima,[3] in contrast to the group's usual full location shootings at Setouchi region points of interest, due to the COVID-19 pandemic. The choreography was created by Tomohiko Tsujimoto, who has choreographed several STU48 songs and envisioned a fantasy-like atmosphere for this music video, in which the performers meet their "alternate selves".[3][4]
"Hitorigoto de Kataru Kurainara" became the theme song for the 2021 animated short film Шаблон:Nihongo4, which was part of a Nippon Foundation campaign to raise awareness about marine debris. Members Marina Otani and Miyuna Kadowaki also served as voice actresses.[4][5][6]
The B-side song Шаблон:Nihongo was performed by the six members who appeared on the final stages of the third AKB48 Group No. 1 Singing Ability Contest in December 2020.[7][8] The Setouchi PR Unit, which members were elected using ballots included with the previous single, performed Шаблон:Nihongo led by top-voted member Miyuna Kadowaki.[9][10] "Sunglasses Days" was performed by all full members (excluding trainees).[11]
The single was released on February 17, 2021 in five versions: limited and regular editions of Types A and B and a Theater edition.[12]
