Zuori Qing Kong  

Crystal Sky of Yesterday, 昨日青空

In the 90s in china, tu xiaoyi, a high school student, disregarded grades and spent more time playing video games with his friend "peanut." later, he was appointed class representative alongside yao zhetian, a popular girl. this marked the beginning of his romantic journey, which included both joy and heartbreak.

Manhua artist Pocket Chocolate began production of a full-length animation film adaptation of his work Zuori Qing Kong (published outside China as Crystal Sky of Yesterday) in July 2015, after seeking feedback on a sample pilot adaptation. The films target audience is viewers born in the 1980s and 1990s. In order to prepare for production, the animation team spent time studying the Lanxi cityscape, including finding textbooks, school desks, and bicycles used in the films time period.