Seven children, or Seven baby crows, The crow's seven chicks)[1][2][3] is a popular[3] Japanese children's song with lyrics written by Ujō Noguchi (野口雨情 Noguchi Ujō) and composed by Nagayo Motoori (本居 長世 Motoori Nagayo).
[1][3] Nanatsu no ko is used as the departure melody at Isohara Station in Kitaibaraki and also as 6 p.m bell in Japan Advanced Institute of Science and Technology at Nomi, Ishikawa.
The song is sung by a nondiegetic children's choir in the 1954 Kinoshita Keisuke film Twenty-Four Eyes.
In the manga and anime Detective Conan by Gosho Aoyama, the mail address of the boss of the Black Organization is #969#6261, which reproduces the beginning of Nanatsu no Ko.
The song is sung in the anime Magical Girl Ore episode 10 by Mohiro to console a lost child.