Mou Hitotsu no Umi
もうひとつの海 · もう ひとつ の うみ
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Contains the following stories: - Mou Hitotsu no Umi (もうひとつの海) - Teenage - Swimmer Five chapters in total, with the first two being on Karino Yoshihito*. Third chapter's kinda on him too, but it's from the point of view of a classmate. Chapter 4's an innocent story of a girl who has to learn how to swim (school life tag's for this chapter and the previous one). The ending chapter is a short slice of life piece on the mangaka's experience with colors and painting since young. *recurring main character in some of Nishi Keiko's stories; see "Mizu ga Kooru ni Naru Toki" and "September"
Source: AniList
External databases: MADB · AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections