Maiden and Promise

Seigakukan is a school where students come to match their skills in ferocious duels! There is only one iron clad rule: if you lose, you're honor bound to obey the winner until you win back your freedom. Chigiri Futaba is obsessed with avenging her dishonored family, but to do that she has to beat Zawa Kaguya, the student council president, in a sword fight. The problem is that Kaguya is the school's supreme swordswoman -- and she's already added Futaba to her harem of conquests.