I am reading Chan Buddhism by Peter D. Hershock. It describes how Chan evolved from Buddhism, Confucius's teachings, and Taoism. Chan was one of five schools of Buddhism in China in the fifth century CE.
The teachings of Confucius and Lao Tsu had more followers than Buddhism. However, a Chan approach reflects a mid-point between these two, not unlike Shakyamuni Buddha's middle-way construct in India. In tracing the lineage from Bodhidharma through Huineng, the author underlines emerging Chinese Buddhism as cultural variation from its Indian roots.
Buddha Nature without boundary, parsing, or definition, is referred to as sunyata-emptiness. Through the interrelationship of existence, individuals experience insight. This sudden awakening is something unseen in our ignorance.
What then do we do with this insight? In the life of Chan practice, the moment is inclusive, all is open and we become more wide-awake by engaging or sharing this truth/Dharma.