The World's Greatest First Love: The Case of Ritsu Onodera (世界一初恋 〜小野寺律の場合〜, Sekai-Ichi Hatsukoi: Onodera Ritsu no Baai, also alternatively known as Sekai Ichi Hatsukoi: The World's Greatest First Love in the English anime) is a Japanese yaoi manga series written and illustrated by Shungiku Nakamura. In 2011, the manga was adapted into an anime television series. Produced by Studio Deen under the direction of Chiaki Kon, the anime series began its broadcast run on April 9, 2011. An original animation DVD was bundled with the fifth and sixth volumes of the manga series, released in March and September 2011. A film adaptation was released on March 15, 2014.