Otome no Iroha!
乙女のいろは! · おとめ の いろは
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Iroha, a masculine girl and Hifumi, a feminine boy are siblings who has transfered to a different middle school and moved to their grandparents house. However, after the first night much to their surprise... Note: includes chapter 5.5
Source: AniList
External databases: MADB · AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections