This paper compares Huineng’s Platform Sutra with Shenxiu’s Treatise on the Contemplation of the Mind (觀心論Guanxin Lun), and finds that both belong to the Tathāgatagarbha system, and both think of practice as a manifestation of the original pure Buddha nature; they both talk about Buddha Dharma (ten thousand dharmas) based on the nature of mind; both advocate sudden enlightenment, and their teaching methods belong to the teachings of sudden enlightenment. There is no essential difference between Shenxiu’s and Huineng’s views. Their Chan principles both come from their teacher Hongren. This conclusion is different from the popular saying of “sudden in the south, gradual in the north”, which should be further interpreted.