Otokujuku Gaiden: Kurenai!! Onnajuku

Overview

Thirty years after World War III, Japan has suffered immense damage from a dangerous weapon known as a "Man Bomb" which affected nearly all Japanese men and rendered them unable to fight, with other men giving their lives for their country. Heihachi Edajima, an Otokojuku veteran and survivor of the Man Bomb, starts up a new facility known as Onnajuku, a tough combat training facility, and begins training several Japanese women to fight for their country. The manga follows Momoko Tsurugi, a descendant of former protagonist Momotarou Tsurugi, who recently enrolls in Onnajuku. As spirited and tenacious as her ancestor, Momoko's catchphrase is "As a woman, I ain't dying! I, Momoko Tsurugi, will show you my burning youth!" (Source: Anime News Network)

Source: AniList