A controversy that arose between two factions of pre-classical Ch'an during the early 8th century whose polemics centred on the positions of ‘sudden enlightenment’ (the ‘subitist’ position) (see subitism) and ‘gradual enlightenment’ (the ‘gradualist’ position). The traditional account of the controversy is found in the Platform Sūtra of the Sixth Patriarch. According to this Chinese text, both Shen-hsiu and Hui-neng were disciples of the fifth patriarch Hung-jen (601–74). As Hung-jen was preparing to pass the title of sixth patriarch to his successor, he asked his disciples to compose a poem that would demonstrate their level of enlightenment (bodhi). All the other monks deferred to Shen-hsiu, the senior disciple. Shen-hsiu composed a verse which Hung-jen publicly praised while telling Shen-hsiu in private that it fell short of the mark. When Hui-neng heard about the contest, he instantly knew what to write and, being illiterate, had a temple page inscribe his verse on a wall. Hung-jen, hearing of this, said publicly that this verse was lacking, but late that night called Hui-neng to his room and ‘transmitted his Dharma’ to him, naming him as his successor and sixth patriarch, and giving him the robe and bowl of Bodhidharma as tokens. In traditional Ch'an literature, Shen-hsiu's verse puts forward the gradualist position while Hui-neng's expresses the subitist position, and Hung-jen's approbation of the latter's verse is meant to demonstrate that the subitist position is the true teaching of the patriarchs.
Thus, in Ch'an documents, the Northern School (the name given to the line of disciples coming from Shen-hsiu) is represented as teaching the position of ‘gradual enlightenment’. From a philosophical viewpoint, ‘gradual’ here does not necessarily mean taking an extended period of time to achieve enlightenment, but indicates the dualistic view that differentiates enlightenment from ignorance or practice from attainment. No matter what length of time one specifies from the beginning of practice to the attainment of enlightenment, it becomes ‘gradual’ only because the two are separated. According to teachings of Buddha-nature that had been current in China from the 4th century onwards, all sentient beings have the capacity to be Buddhas. Teachings of ‘sudden enlightenment’, which became standard doctrine within Ch'an after the controversy, posit Buddha-nature as an already fully endowed Buddhahood inherent in all beings, in light of which enlightenment takes literally no time at all, since practice and attainment are collapsed. Thus, on this reading, the Northern School adhered to a position of untenable dualism, and so fell out of the mainstream.
A historical examination of the controversy reveals many problems with the traditional account of both the events themselves and the views ascribed to each side. There is good reason to think that the two protagonists in the poetry contest, Shen-hsiu and Hui-neng, never resided at Hung-jen's monastery on Tung Shan at the same time. Furthermore, the Northern School's views on practice and enlightenment reveal a subitist position, while Southern School literature written during less heated moments frankly acknowledges the need to spend time preparing oneself for the moment of ‘sudden’ enlightenment. Ironically, during the Council of Lhasa held in Tibet in 792 to debate the subitist and gradualist positions, Indian monks argued the gradualist position, and a Northern School monk represented the subitist position.