is a song by Japanese rock duo Yorushika from their fifth studio album Second Person. It was released as a single by Polydor Records on January 5, 2024, and served as the second opening theme for the 2023 Japanese anime series Frieren: Beyond Journey's End. Commercially, "Sunny" peaked at number 11 on the Oricon Combined Singles Chart and number eight on the Billboard Japan Hot 100, and received Double Platinum certification for streaming by the Recording Industry Association of Japan (RIAJ).
On December 22, 2023, following the release of Frierens 16th episode, "Long-Lived Friends", a snippet of "Sunny" was used in Frierens fourth trailer, revealing Yorushika to be in charge of the series' second opening theme. The song was available digitally on January 5, 2024, the same day as Frierens 17th episode, "Take Care", premiered.
N-buna, a half-member of Yorushika and the songwriter, stated in a press release that "Sunny" is about "hoping for sunny days when the weather is not sunny." Ryà Âhei Ohara from ' noted that the lyrics of the song are more abstract than Frierens first opening theme, "Yà «sha" by Yoasobi, but evaluated it as "a song that fits closely with the anime." Eriko Ishii of Real Sound was surprised by "the raw emotion expressed in the powerful words that come out of the chorus," and praised Suis's vocals as "not a voice that tells a story, but a voice that is determined to convey a strong message to the listener."
An accompanying animated music video for "Sunny" premiered on March 5, 2024. It was directed by Kohta Morie, who previously worked on several of Yorushika's music videos. The visual was initially meant to premiere close to the song's release date, but following a request from Yorushika to not compromise on the quality, the release was pushed back two months. Inspired by Haruki Murakami's 1985 novel Hard-Boiled Wonderland and the End of the World, the story depicts a child and his father living in a town surrounded by impenetrable wall. A special version of the music video, featuring footage from the Frieren anime, was uploaded on March 29.
A rearranged version of "Sunny" was used for Suntory Gin's Sui online commercial "Sui to Utaeba".