Azumanga Daioh: Supplementary Lessons (Japanese: あずまんが大王·補習編 Azumanga Daiō Hoshūhen) is a series of 6 new chapters for the Azumanga Daioh manga, which was written in June to August 2009 and serialized in Shogakukan's Monthly Shonen Sunday to celebrate the 10 year anniversary of the manga. Like the original chapters, the chapters of Supplementary Lessons were written and illustrated by Kiyohiko Azuma.
2 new chapters were created for each year of school, which means that the first two chapters contain events that were never seen in the original manga but that occured during the characters' first year of school, the second two chapters record missing events from the second year, and so on. The new chapters were included in a repackage made of the manga series into a three-volume set, the first volume being released on June 11, 2009.
The chapters are drawn in Kiyohiko Azuma's new drawing style, which makes the art appear similar to that of his current manga Yotsuba&!. The story of these new chapters, like the original Azumanga Daioh series, chronicles the characters' daily lives and what happens to them during various lessons and outside of class. The chapters also cover additional events from the main cast's trip to Chiyo-chan's summer house during year three, and a new dream Sakaki has about Chiyo-chichi.