OL karate nyuumon: Oku made tsuki irete (2009)

Miki, a health food saleswoman, is sighing all day because her sales are still low. To make matters worse, she's attacked by two men on her way home from work at night. She's rescued by Rikiya, the master of a karate dojo, and Miki falls in love with him at first sight, deciding to join his dojo. However, the strict Rikiya rejects Miki, which only makes her more determined.