"六祖壇經" by Huineng is a Chan Buddhist scripture composed in China between the 8th and 13th century. The only Chinese Buddhist text explicitly called a "Sutra," it centers on teachings attributed to the sixth Chan patriarch Huineng. The text explores the concept of Buddha-nature, invisible to humans only through their illusions. It features the famous succession contest between disciples Shenxiu and Huineng, whose competing poems reveal contrasting approaches to enlightenment. The work attempts to reconcile Northern and Southern schools of Chan Buddhism.
Wikipedia page about this book: en.wikipedia.org/wiki/Platform_Sutra