The Secret of Friendship Manga features story by Kazune Kawahara and art by Aiji Yamakawa.

Eiko and her best friend Moe couldn’t be more different. While Eiko is a shy, average-looking girl, Moe is beautiful and constantly gets attention from guys. Though their personalities are total opposites, the bond between them is incredibly strong. Moe might have an endless supply of suitors, but when it comes to actually dating them, she has a condition: her boyfriend must value Eiko more than he does Moe. No one has yet been able to meet her condition—not until a boy named Tsuchida appears, at least. What will Eiko do when her relationship with her best friend begins to change?