Azumanga Daioh: Extra Lessons

To celebrate the 10th anniversary of Azumanga Daioh, the manga was repackaged into a new three-volume set, which included three chapters of new material called "Hoshuuhen" ("Supplementary Materials" or "Extra Lessons"). (https://mangadex.org/title/107be290-6a4b-4974-a9c5-3761a2514823/azumanga-daioh-2009-print) Each new chapter covers one year of high school, with all new adventures for Sakaki, Yomi, Tomo, Chiyo, Osaka, and Kagura.