Rumi-chan's Classroom

(from ebookjapan): Rumi lives with her brother in a shabby apartment. Although she is not rich, she lives a very happy and joyful life. Even though she has not yet started school, she follows her older sister to the fourth grade classroom every day. This is a heartwarming story about the adorable Rumi and the people around her. This is a legendary rare work that is said to be the pinnacle of children's manga.