Imōto wa Shitte Iru
Imōto wa Shitte Iru is a Japanese manga series written and illustrated by Mari Gangi. It began serialization in Kodansha's Weekly Young Magazine in November 2024, and has been compiled into five volumes as of December 2025.
Plot
The series follows Kiichirō Miki, a salaryman who lives with his younger sister Miki. Despite having a boring personality in real life, he is secretly Fruit Parfait, a radio listener known for frequently sending detailed postcards to the program All Night Nippon. However, only Miki is aware of his secret identity.Characters
;Kiichirō Miki;Miki Miki
;Sumine Hirose
;Tsubomi Yokō
;Akari
Publication
The series is written and illustrated by Mari Gangi. It began serialization in Kodansha's Weekly Young Magazine on November 25, 2024. Gangi created the series as they found the concept of "postcard craftsmen", people who create detailed postcards to send to radio programs, interesting. She originally aimed for the Miki siblings to have a more cheerful personality, but changed them to have a more reserved personality at the suggestion of her editor. The first volume was released on March 6, 2025; five volumes have been released as of December 2025.Reception
The series was nominated for the 2025 Next Manga Award in the print category, and was ranked thirteenth. The series has been nominated for the 19th Manga Taishō in 2026.The series received attention online for its discussion on postcard craftsmen, with a tweet promoting the series getting over 50,000 likes on Twitter. Volume one received a reprint a few days after release due to high demand.