In the Heart of Kunoichi Tsubaki Kunoichi Tsubaki no Mune no Uchi

Deep in the mountains in the middle of nowhere lives a group of kunoichi called Akane Class. These kunoichi work hard together to improve their own skills, and they all live by an unbreakable rule: “Contact with men is strictly forbidden.” But everything takes an unexpected turn when Tsubaki, leader of one of the groups, starts experiencing strange feelings whenever the subject of men comes up.

(Source: Crunchyroll)