Caodong school
Shenhui's influence is traceable in the "Platform Sutra", which gives a popular account of the story of Huineng but also reconciles the antagonism created by Shenhui. Salient is that Shenhui himself does not figure in the "Platform Sutra"; he was effectively written out of Chan history. The "Platform Sutra" also reflects the growing popularity of the "Diamond Sūtra" ("Vajracchedikā Prajñāpāramitā Sūtra") in 8th-century Chinese Buddhism. Thereafter, the essential texts of the Chan school were often considered to be both the "Laṅkāvatāra Sūtra" and the "Diamond Sūtra". The "Laṅkāvatāra Sūtra", which endorses the Buddha-nature, emphasized purity of mind, which can be attained in gradations. The Diamond-sutra emphasizes sunyata, which "must be realized totally or not at all". David Kalupahana associates the later Caodong school (Japanese Sōtō, gradual) and Linji school (Japanese Rinzai school, sudden) schools with the Yogacara and Madhyamaka philosophies respectively. The same comparison has been made by McRae. The Madhyamaka school elaborated on the theme of śūnyatā, which was set forth in the prajnaparamita sutras, to which the "Diamond Sutra" also belongs. The shift from the "Laṅkāvatāra Sūtra" to the "Diamond Sutra" also signifies a tension between Buddha-nature teachings, which imply a transcendental reality, versus śūnyatā, which denies such a transcendental reality.