Sekai-ichi Hatsukoi ~Onodera Ritsu no Baai 12~ (世界一初恋 〜小野寺律の場合12〜), or The World's Greatest First Love: The Case of Ritsu Onodera 12, is the twelfth volume of the Sekai-ichi Hatsukoi manga series.
The limited edition will include a 48-page collection of illustrations.
The contents are not yet verified, but the following chapters will likely be included:
- The Case of Kou Yukina No.3
- The Case of Ritsu Onodera No.23
- The Case of Ritsu Onodera No.24