関西弁お姉さんと純真少年 = The Girl with Kansai-accent and the Pure Boy
かんさいべん おねえさん と じゅんしん しょうねん
est. Rough estimate based on volume count, reprints and magazine — not an official figure
External databases: MADB
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections