Kaze Hikaru Vol. 3 (manga)

Sei has returned to the Mibu-Roshi, but Soji hardly seems happy about it. He still believes that the Mibu-Roshi is no place for a girl. Sei makes an agreement with him that if she can't score one hit on him in three days, she'll leave for good and return to living a normal life. However, Sei's got her work cut out for her, as Soji is a master swordsman...