Ohitorisama (2009)

Original title: おひとりさま

33-year-old Akiyama Satomi is a history teacher at the prestigious all-girls high school she once attended. She has earned the nickname "ohitorisama" (meaning "one person") for her perfectionism and capability to handle any work by herself. At the same time, the name also refers to her lack of romance. One day, a young man named Shinichi arrives at the school as a temporary instructor. He's ten years younger than Satomi, has only worked part-time jobs, and has neither money nor status. Although the other female teachers and students find him cute, he is completely not Satomi's type... or is he? Will love blossom between this unlikely pair?