19 days (19天) is a Chinese BL webcomic written and illustrated by artist Old Xian (old先). Some of his other works include Mosspacca Advertising Department, The Specific Heat Capacity of Love, and Xiao Chou Dan Ni (Joker Danny).
19 days tells the hilarious story about the daily school life of a group of hot-blooded teenagers, their touching friendship and personal growth. Featuring characters Jian Yi (见一) and Zhan Zheng Xi (展正希), who are childhood friends, the handsome He Tian (賀天) and the reluctant Mo Guan Shan (莫关山).
Chapters and Volumes
Jian Yi 
A ‘natural airhead’ boy, cute and charming. The pale eyebrows and soft looking ash hair are his trademark. He has complicated feelings towards his best friend and struggles with his emotions. His mother is often absent and he hides how he truly feels in order to keep going.
A good-looking senior gamer. He is especially loyal to friendship and as Jian Yi’s best friend, he would defend Jian Yi first when he needs him.
He Tian 
The most popular boy in school. He is a top student and good at basketball. He loves to flirt and play around with Mo Guan Shan.
Mo Guan Shan 
A trouble maker, an outcast who comes from a lower class background. His father is in prison and his mother struggles with making a living, so he is always short of money. His most prominent feature is his natural red hair and he has trouble interacting with others.
- The first 14 chapters take place after Jian Yi's return. The subsequent chapters to date is a chronological flashback to their middle school days.
- He Tian's first unofficial appearance is in early chapters was the faceless guy who touches Jian Yi's hair.
- In some of the official illustrations, both Jian Yi/Zhan Zheng Xi and He Tian/ Mo Guan Shan are hinted to be in a romantic relationship in the future.
- The Western ship names for each couple are Zhanyi for Zhan Zheng Xi/Jian Yi, Tianshan for He Tian/Mo Guan Shan. The Chinese ship names for each couple, "炸贱" for Zhan Zheng Xi/Jian Yi and "贺顶红" for He Tian/Mo Guan Shan. The ship name Tianshan is also affectionately called 'Heavenly Mountain' by fans, the English translation for the ship name; giving it a special and intimate meaning.