is a Japanese manga series written and illustrated by Sà Âichirà  Yamamoto. It was serialized in Shogakukan's manga magazine Monthly Shà Ânen Sunday from January 2018 to May 2023, with its chapters collected in nine volumes. An anime television series adaptation produced by CloverWorks aired from April to July 2022.
Tsubaki, a kunoichi and the best student of the Akane Class, lives in a village where women are not allowed to have contact with men. However, she has a curiosity about them that she wants to keep hidden.
Written and illustrated by Sà Âichirà  Yamamoto, In the Heart of Kunoichi Tsubaki was serialized in Shogakukan's manga magazine Monthly Shà Ânen Sunday from January 12, 2018, to May 12, 2023. Shogakukan collected its chapters in nine volumes, released from July 12, 2018, to August 9, 2023.
On November 9, 2021, Aniplex announced an anime television series adaptation produced by CloverWorks. The series was directed by Takuhiro Kodachi, with the scripts handled by Konomi Shugo, character designs by Yousuke Okuda, and music composition by Yà «suke Shirato. It aired from April 10 to July 3, 2022, on Tokyo MX and other networks. The opening theme song is by the Peggies. For each episode, different cast members performed a version of the ending theme song as their respective teams. Crunchyroll streamed the series. Medialink has licensed the series in Asia-Pacific.
In 2020, the manga was one of the 50 nominees for the sixth Next Manga Awards.
The anime adaptation was one of the 100 nominees for the Anime Fan Award during the 2023 Tokyo Anime Award Festival, placing fourth behind Tiger & Bunny 2, Uta no Prince-sama: Maji Love 1000%, and Mechamato.
Anime News Network reviewers Caitlin Moore, Richard Eisenbeis, Nicholas Dupree, James Beckett, and Rebecca Silverman greatly criticized the premise, calling it "contrived, uncreative, and unfunny". While some praise was given to its art style, the series was also criticized for its "questionable artistic decisions", referring to the character designs and outfit choices.