Gunjō ni SirenGunjō ni Siren.

Gunjō ni Siren (Japanese: 群青にサイレン, Hepburn: Gunjō ni Sairen; "Ultramarine Siren") is a Japanese baseball-themed manga series written and illustrated by Mikan Momokuri. It was serialized in Shueisha's josei manga magazine You from July 2015 to October 2018, until the magazine ceased its publication. It was later serialized on Shueisha's online platform Shōnen Jump+ from February 2019 to August 2020.