Sekai-ichi Hatsukoi: Onodera Ritsu no Baai (世界一初恋 〜小野寺律の場合〜, lit. "The World's Greatest First Love: The Case of Ritsu Onodera") is a Japanese BL manga series written and illustrated by Shungiku Nakamura. In 2011, the manga was adapted into an anime television series under the title Sekai-ichi Hatsukoi. Produced by Studio DEEN and directed by Chiaki Kon, the anime adaptation began its broadcast run on April 9, 2011. An original animation DVD was bundled with the 5th and 6th volumes of the manga series, released in March and September 2011.
Plot- Ritsu Onodera, a literature editor, resigns from his father's publishing company due to his coworkers' jealousy of his success, claiming that he is simply riding his father's business. He applies for a position at Marukawa Publishing, but instead of his preferred department of literature, he is placed in the infamous shojo manga department, Emerald. He initially considers resigning, because he finds his new boss, Masamune Takano, intolerable and unnerving from the very beginning. However, Takano inadvertently convinces Onodera to stick with the job by calling him "useless," his pride forcing him to stay in order to prove his worth. Later, Onodera learns that Takano's old family name was Saga, and Masamune Saga was an older schoolmate from high school who Ritsu fell in love with and confessed to.