Aya Tachibana (橘文 Tachibana Aya) is Sae's pen name used for her stories published in Kirara Monthly. Aya Tachibana's popularity is such that issues with her work in it tend to sell out with astonishing speed.
The pseudonym is a closely guarded secret at school -- she did not even tell it to Yuno and Miyako until they found one of her manuscripts and discovered it for themselves. It is known to her family, including her sister Chika. It has also apparently been discovered by Natsume, who is a huge fan. Hiro, who knew the pseudonym from the beginning, has had high praise for the writer's "gentle" style.
The Aya Tachibana stories are mostly about teenage life and love. Sae claims they are inspired by personal experience, a claim her friends do not really believe. Due to the popularity of her work, her editor Naoi has requested numerous stories from Sae on tight deadlines, which frequently result in Sae working herself to exhaustion, pretending she is not home to avoid meetings, or both.