Sekai-ichi Hatsukoi Wiki
Sekai-ichi Hatsukoi Wiki

The Case of Chiaki Yoshino (世界一初恋 〜吉野千秋の場合〜, Sekai-ichi Hatsukoi: Yoshino Chiaki no Baai) is a light novel in the Sekai-ichi Hatsukoi series written by Fujisaki Miyako and Shungiku Nakamura. It follows Chiaki Yoshino as well as his long-time childhood friend, Yoshiyuki Hatori, as they deviate from their original friendship, into a romantic relationship.



Chiaki Yoshino is a 28-year-old manga artist working with Yoshiyuki Hatori as his editor. Together since childhood, the two had even stayed together into their adult careers. Hopeless in the kitchen, and extraordinarily dense, it's not unreasonable that he failed to notice his childhood friends' feelings for him.

After witnessing Hatori and his best friend, Yuu Yanase, in a seeming lovers position, Chiaki comes to the conclusion that the two of them are dating and that they have kept it a secret from him. His situation only becomes more confusing after falling asleep on his couch, and being woken up to Hatori kissing him. Once the kiss breaks, Chiaki attempts to ask him if he's gay, but without answering, Hatori proceeds to bind Chiaki's hands. Too slow to stop him, Hatori then forces himself on a confused Chiaki. In an astounding amount of pain, he comes to the conclusion that he's just a replacement for Yuu, furthering his own depression with the incident.

Chiaki passed out shortly after coming to that conclusion, proceeding to avoid all contact with Hatori aside from business emails and calls. He admits to himself that if had been anybody else, he would've called the police. Had it been any other friend, he would've ceased all contact with them. However, for Chiaki, ceasing all contact with Hatori is not an option. Hatori later texts Chiaki asking him if he'd still like to attend the firework show that he had wanted to see as a reference for his next manga. Chiaki agrees, deciding he would try to forget what had happened despite how traumatic it had been in an attempt to not lose Hatori.

At the firework show, Hatori tells Chiaki that he will no longer be his editor, and that what he did had ruined all of the trust an author could have in their editor. Hatori also apologizes for forcing himself on Chiaki, promising that it won't happen again. Afraid to lose Hatori, Chiaki demands that Hatori kiss him so that he could prove that it wasn't disgusting. Chiaki also promises that if it feels disgusting to him, he'll tell Hatori immediately. After a bit of conversation on this, Hatori agrees and the two kiss. Since the kiss didn't feel disgusting to him, the two begin dating.

summary in progress


Sekai-ichi Hatsukoi light novels


The Case of Chiaki Yoshino

Volume 1Volume 2Volume 3Volume 4 • Omnibus volume 1Omnibus volume 2

The Case of Yoshiyuki Hatori

Volume 1Volume 2


The Case of Takafumi Yokozawa

Volume 1Volume 2Volume 3Volume 4Volume 5Volume 6Omnibus volume 1Omnibus volume 2Omnibus volume 3

The Case of Animate

Volume 1