The Ambition of Oda Nobuna (2012)

The historical romantic comedy follows 17-year-old high schooler Sagara Yoshiharu who one day time-travels to the Sengoku period, where all the major Samurai lords are cute girls. Yoshiharu meets Oda Nobuna, the girl counterpart of Oda Nobunaga, and begins to serve her as a substitute of Kinoshita Toukichirou, who has been dead in the world.