is a Japanese romantic comedy light novel series written by Yu Hibari and illustrated by Shiso. It was serialized online from June 2020 to July 2026 on the user-generated novel publishing website Shōsetsuka ni Narō, before later acquired and published by Kadokawa Shoten under their Kadokawa Sneaker Bunko imprint in eleven volumes from February 2021 to July 2026. A manga adaptation with art by Kina Ōyama was serialized online by Fujimi Shobo via Niconico Seiga website as part of the Dra Dra Flat brand from September 2021 to June 2025, and was collected in seven volumes. An anime television series adaptation produced by Project No.9 aired from July to September 2026.

Plot Hayato Kirishima and Haruki Nikaido were close childhood friends who lived in a rural town. However, they separated after Haruki moved away. Seven years later, Hayato now finds himself in the city where Haruki moved to and transfers to a new school. There, he meets a beautiful girl, who initially acts strange towards him. However, they quickly realize that she is Haruki, his old friend. The two rapidly reconnect and start a relationship, as Hayato finds himself discovering new feelings for Haruki he never knew he had.

Characters

A high school student who has just transferred to Haruki's school. Seven years ago, before Haruki moved away, the two promised to always be together, but the two lost contact and did not meet again until their reunion. He develops a crush on Haruki shortly after their reunion, and tends to get slightly jealous whenever other boys flirt with her. Eventually, he confesses to her, and they get married at the end of the story.

Hayato's childhood best friend. During their reunion, Hayato did not recognize her as the Haruki of their childhood had a tomboyish appearance. She has now become a beautiful and popular girl. She still has the GameCube they used to play with when they were younger. Like Hayato, she also develops feelings for him after their reunion, but denies this every time. She is actually the daughter of the popular actress Mao Takura. By the end, they grow up and get married, having twin children.

A playful, outgoing young girl and Hayato's younger sister. She always looked up to Haruki during their early childhoods.

A timid but kind girl and Hayato and Haruki's classmate. Although Minamo is a member of the Gardening Club, she lacks any knowledge of plants. Other classmates confuse her and Hayato for being together, though they always deny it. Eventually, she admits she sees Hayato as a brother figure, and looks up to Haruki as her closest friend. She has a very overprotective grandfather that constantly bothers her.

A farmer girl from Hayato and Haruki's childhood who always had a big crush on Hayato in secret, but hid it from him behind an externally cold personality. She views Haruki as her rival for Hayato's affections, but eventually starts befriending her after realizing her feelings for Hayato are completely one-sided.

A popular television and movie actress. She is actually Haruki's mother. Towards the end of the series, she and Haruki appear in a movie together, but she dies of illness before the film is released.

Media Light novels Written by Yu Hibari, Oh Boy, Was I Wrong About Her was serialized online on the user-generated novel publishing website Shōsetsuka ni Narō from June 13, 2020, to July 31, 2026. The series was later acquired and published by Kadokawa Shoten as a light novel in eleven volumes with illustrations by Shiso from February 27, 2021, to July 31, 2026.

In September 2026, Yen Press announced that it had licensed the series for English publication.

Manga A manga adaptation illustrated by Kina Ōyama was serialized by Fujimi Shobo on the Niconico Seiga website under the Dra Dra Flat brand from September 2, 2021, to June 26, 2025. Seven volumes were released from April 8, 2022, to July 9, 2025.

Anime An anime adaptation was announced during Kadokawa's "Sneaker Bunko 35th Anniversary Festa!" livestream on September 24, 2023, which was later revealed to be a television series that is produced by Project No.9 and directed by Xu Chuan Feng, with Deko Akao handling the series composition, N-Nei Kurahashi designing the characters, and Ryosuke Nakanishi, Naoki Tani, and Yuri Morita composing the music. The series aired from July 6 to September 21, 2026 on Tokyo MX and other networks. The opening theme song is , performed by Dialogue+, and the ending theme song is "Tilt", performed by Harmoe. Crunchyroll is streaming the series.

Episodes

See also The World's Least Interesting Master Swordsman, another light novel series with the same illustrator

Notes

References

External links at Shōsetsuka ni Narō at Kakuyomu at Kadokawa Sneaker Bunko at KadoComi at Niconico Seiga