Azuma Otoko Kyou Otoko
東オトコ京オトコ · あずまおとこ きょうおとこ
est. Rough estimate based on volume count, reprints and magazine — not an official figure
Overview
Souma was transferred from the Tokyo branch to the Kyoto branch. The day he moved in, the landlord's son Amane returned home, and thus, they ended up being roommates. Souma thought roommates should be friendly, but Amane is pretty aloof. But after accidentally seeing Amane cry, Souma keeps thinking about him... (Source: Shinshokan, translated) Note: Includes an extra chapter.
Source: AniList
External databases: MADB · AniList
How to compare editions, collected volumes and ISBNs / Sources, updates and corrections