The Sixth Patriarch Hui-neng (638-7l3) offered some novel formulations of zazen. In his Platform Sutra (Liu-tsu t'an ching), he says that if one were to stay free from attachment to any mental or physical realms and to refrain from discriminating, neither thoughts nor mind would arise. This is the true "sitting" of Ch'an. Here the term "sitting" is not limited to physical sitting but refers to a practice where the mind is not influenced or disturbed by anything that arises, internally or in the environment. For Hui-neng, the direct experience of Self-nature, the seeing of one's own unmoving Buddha-nature, is called "Ch'an." One could say that true sitting is the method, Ch'an the result. Yet since Ch'an is sudden enlightenment, when it occurs it is simultaneous with zazen. Hui-neng was critical of certain attitudes in practice which did not conform to his criteria of the true zazen that leads to Ch'an. Such "outer path" approaches to sitting are illustrated in the following two anecdotes.