The second official guidebook in the “Sound! Euphonium” series, “Kitauji High School Wind Ensemble Diary 2,” will be released by Takarajimasha on Thursday, September 10, 2026. This is the second official fanbook based on the original series in a decade, featuring four newly written short stories—including one about Kumiko and Reina’s outing—as well as a manga adaptation by Asada Nikki, an interview with Ayano Takeda, and a poster of Kumiko and Reina.