Sekai de Ichiban Yasashii Ongaku

A cute and touching story of a single mother, Sumireko, and her daughter, Nozomi. The manga starts off with Nozomi being sixteen years old in the first chapter, then hops back to before she was born. Finally with the third chapter starts the "real" story, when Non-Non (Nozomi) is three years old.

(Source: Dragon Voice)