The Ambition of Oda Nobuna (織田信奈の野望) is a Japanese light novel series written by Mikage Kasuga and illustrated by Miyama-Zero, that was adapted into an anime television series that premiered in July 2012 and currently ongoing.

Plot:
Suddenly finding himself in the Sengoku era, regular high school student Yoshiharu Sagara is about to be killed in the battlefield. He is saved by none other than the man who later becomes the respected Hideyoshi Toyotomi, though at a cost to the latter's life. With history completely changed because of Yoshiharu’s actions, he tries to make things right again. However, history takes a different course than the one he learned and Yoshiharu meets a brilliant but young girl named, Nobuna Oda. Yoshiharu starts working under her command to bring back history to its correct course and find his way back home to the present world.

Source:Wikipedia