Takemiya Keiko manga
From Stiletto Heels: Douzono Tsugumi, who works for a major electrical company, spends her vacation at her grandmother's home in the country. Her grandmother soon passes away during hospitalization, and Tsugumi decides to continue living in her grandmother's house. However, a mysterious man shows up holding the key to the rear house, and despite not fully comprehending the relationship he had with her grandmother, they begin living together. Nominated for the 3rd Manga Taisho Award (2010).
From Aerandria Scans: Endou Kana is a cheerful school girl who has a secret crush on... the mayor, Minato Kouichi, a perfect gentleman and well-liked leader of the post-war town. With the help of her friend Akira, she investigates him, until the trail leads her to an abandoned-looking house where a strange and scary foreigner lives. He and Kouichi seem to have some kind of relationship, but what is it? Kana's and Akira's take on that question are completely different and there's still a chance both of them are wrong!
Taken from Baka-updates: An anthology of oneshots. Story 1: Promise by NISHI Keiko Story 2: They were Eleven by HAGIO Moto Story 3: The Changeling by SATO Shio Story 4: Since You've Been Gone by NISHI Keiko The two stories by NISHI Keiko were also published as a separate book in English called "Promise." Those stories were originally taken from "Mizu ga Kooru ni Naru Toki."
Yori Iwatani is close to her 40s and is giving up on love and marriage. She has decided to live a quiet solitary life in her hometown. But when a handsome former classmate appears, things change for her.