To transmit the Dharma and to save all from error
As the story goes, Hui-k'o remained at the Shao-lin for a while longer and then went underground, supporting himself through menial work and learning about Chinese peasant life firsthand. Reportedly, he wanted to tranquilize his mind, to acquire the humility necessary in a great teacher, and not incidentally to absorb the Lankavatara Sutra. When asked why he, an enlightened teacher, chose to live among menial laborers, he would reply tartly that this life was best for his mind and in any case what he did was his own affair. It was a hard existence, but one he believed proper. Perhaps it was in this formative period that the inner strength of Ch'an's first Chinese master was forged.
Hui-k'o's major concern during this period must inevitably have been the study of the Lankavatara Sutra entrusted him by Bodhidharma. The Lankavatara was not written by a Zen master, nor did it come out of the Zen tradition, but it was the primary scripture of the first two hundred years of Ch'an. As
D. T. Suzuki has noted, there were at least three Chinese translations of this Sanskrit sutra by the time Bodhidharma came to China.6 However, he is usually given credit, at least in Zen records, for originating the movement later known as the Lankavatara school. As the sutra was described by a non-Ch'an Chinese scholar in the year 645, "The entire emphasis of its teaching is placed on Prajna (highest intuitive knowledge), which transcends literary expression. Bodhidharma, the Zen master, propagated this doctrine in the south as well as in the north, the gist of which teaching consists in attaining the unattainable, which is to have right insight into the truth itself by forgetting word and thought. Later it grew and flourished in the middle part of the country. Hui-k'o was the first who attained to the essential understanding of it. Those addicted to the literary teaching of Buddhism in Wei were averse to becoming associated with these spiritual seers."7
The Lankavatara purportedly relays the thoughts of the Buddha while ensconced on a mountain peak in Sri Lanka. Although the work is notoriously disorganized, vague, and obscure, it was to be the stone on which Hui-k'o sharpened his penetrating enlightenment. The major concept it advances is that of Mind, characterized by D. T. Suzuki as "absolute mind, to be distinguished from an empirical mind which is the subject of psychological study. When it begins with a capital letter, it is the ultimate reality on which the entire world of individual objects depends for its value."8 On the question of Mind, the Lankavatara has the following to say: