Sakatano Kintoki

A girl who was disguised as a boy at an early age to protect her against the enemies of her house. While disguised as a boy Kintokis cousin Princess Ouni falls in love with her not realizing that Kintoki is actually a girl. Kintoki fled from her cousins love and becomes hunted by her scheming uncle until she is rescued by a noble samurai warrior Lord Raiko. Kintoki spends the next few years under Lord Raikos protection learning how to use a sword. Kintoki eventually joins with Lord Raiko and his subordinates and becomes a warrior entrusted with protecting the city from bandits. Source: ANN