| Ja Kanji: | 永遠の831 |
| Ja Romaji: | Eien no Hachisanichi |
| Genre: | Adventure |
| Type: | tv film |
| Director: | Kenji Kamiyama |
| Music: | Go Shiina |
| Studio: | Craftar |
| Network: | Wowow |
| Released: |
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| Runtime: | 105 minutes |
is an original Japanese animated television film written and directed by Kenji Kamiyama, with animation production by Craftar.
It premiered on television on Wowow on January 30, 2022. It was later released in theaters in Japan on March 18, 2022.
The film was announced on August 3, 2021, to coincide with the 30th anniversary of Wowow.[1] It is written for the screen and directed by Kenji Kamiyama and its animation production is by Craftar.[2] Go Shiina composed the music. The film premiered on Wowow on January 30, 2022.[3] Its main theme is "Hitohira no Mirai" performed by angela, while the opening theme is "Kingyo Bachi", performed by .[4] After the television premiere, it was announced that the film would also be released in Japanese theaters on March 18, 2022.[5] The film had a limited theatrical release in the UK on December 13, 2022 via Anime Limited.[6]