A non-credit opening video for 「映画ちいかわ 人魚の島のひみつ」 (Eiga Chiikawa: Ningyo no Shima no Himitsu), the theatrical anime film based on Nagano‘s original work, has been released to the public.
An Opening Sequence Conceived by Nagano
The opening was structured by Nagano himself and begins with Chiikawa waking up. It follows Chiikawa doing radio calisthenics, then shuffling along sleepily while Hachiware snaps photos of the moment, with Usagi joining the group along the way — all set to the opening theme 「くつずれ」, sung by Hachiware.
Beyond the main trio, the sequence also features Momonga, Kurimanju, Rakko, Shisa, the used bookstore owner, as well as Yoroi-san, Ano Ko, and Dekatsuyо. Everyday scenes such as weeding, sticking lemon stickers, and monster-slaying rounds out the lively montage.
Cast Comments
Five cast members shared their thoughts alongside the video’s release.
Iguchi Yuka (Momonga)
Iguchi expressed her delight at the film’s release, noting she attended the opening day screening herself. She was moved by how cute, fun, and visually impressive the film looked on the big screen — particularly the detailed facial expressions and the sparkling light on the ocean. She singled out Chiikawa’s expression by the campfire near the end as a personal favorite, and said she had a blast voicing Momonga’s free-spirited, unstoppable personality.
Asai Takayuki (Kurimanju)
Asai thanked audiences for coming to theaters and reflected on how the characters — small and weak, yet fiercely devoted to those they love — moved his own heart deeply during recording. He expressed hope that their warmth would reach viewers’ hearts just as powerfully.
Uchida Yuma (Rakko)
Uchida touched on the island-set story, describing a mix of delicious food and moments that call for courage. He said he got excited seeing Rakko show off skills befitting a high-ranking fighter, and hoped the memories from the island would stay with audiences as something precious.
Shimabukuro Miyuri (Shisa)
Shimabukuro said she focused on conveying Shisa’s slightly more upbeat and excited energy while on the island, including a moment where Shisa spontaneously breaks into song. She highlighted a scene featuring “Shimajiro” producing wave sounds and ocean scents to lull the Siren to sleep as a personal favorite, and encouraged everyone to make it a memorable summer experience.
Harumi Momono (Used Bookstore Owner)
Harumi shared that she had been following the original series even before being cast, making her participation all the more meaningful. She was captivated by the characters’ sparkling eyes and the beautiful sea on the big screen, and described the bookstore owner as earnest and kind. Her favorite scenes include Hitoha slowly approaching the mermaid and the campfire scene where Hitoha and Chiikawa lock eyes — she has already seen the film three times in theaters.
¥8.07 Billion in 20 Days
「映画ちいかわ 人魚の島のひみつ」 opened in Japanese theaters on July 24 and surpassed ¥8.07 billion in box office revenue with over 5.63 million admissions within just 20 days of release.

