Zutto Otokonoko dato Omotteita Gaki Taishou ga Onnanoko deshita  

The Kids Leader Who I Thought Was a Boy Is Actually a Girl, ずっと男の子だと思っていたガキ大将が女の子でした, The Gang Leader Who I Thought Was a Boy Is Actually a Girl, 一直以为是男孩子的孩子王其实是女孩子

Upon reuniting with his childhood acquaintance, who he initially believed to be male, he learns that she is now a stunning young lady. They embark on a romantic outing at the park together, experiencing both pleasant and unpleasant moments.

Zutto Otokonoko dato Omotteita Gaki Taishou ga Onnanoko deshita began as a web manga released on the authors Twitter account on February 27, 2020. The series has been published as doujinshi from July 19, 2020 to November 21, 2020.