Chiikawa the Movie: The Secret of the Mermaid Island — the first anime feature film inspired by Nagano's web manga series — surpassed 3.5 million admissions and 5 billion yen (31.5 million USD) in box office revenue within 14 days of its release. The film's official X (formerly Twitter) account reported the news today. Chiikawa the Movie: The Secret of the Mermaid Island opened in 447 theaters across Japan (382 standard theaters + 65 IMAX theaters) on July 24, debuting at No .1 at the top of the weekend box office with 2,240,333,500 yen (14.15 million USD) from 1,508,538 admissions. In its second weekend, the film moved to second place, bringing its 10-day cumulative total to 4.4 billion yen (27.78 million USD) from 3.05 million admissions. The number of days it took for recently released Japanese animated films to reach 5 billion yen in box office revenue is as follows: Detective Conan: Fallen Angel of the Highway (2026 / within 10 days), HAIKYU!! The Dumpster Battle (2024 / within 17 days), Chainsaw Man - The Movie: Reze Arc (2025 / within 17 days), THE FIRST SLAM DUNK (2022 / within 23 days), and Demon Slayer: Kimetsu no Yaiba Infinity Castle I ( 2025 / within 3 days).