Bodhidhamra simply transmitted the mind-seal which is above all letters; directly pointing to mind itself (i.e., pure Mind) he led people to see their real nature and attain Buddhahood.— Zen master T’an-ying (985–1061)
During the Northern Sung Dynasty (960–1127) the Zen realization (siddhanta) was controversial. It placed exegesis, which was dependent on Sutras and Shastras, below self-realization which was claimed, in fact, to transcend the Sutras themselves. The basis for this radical view rested on the transmission of the Mind-seal that was of paramount importance in the Zen representation of Buddhism. (It should be grasped that a Mind-seal confirms itself, i.e., is its own imprimatur.) This seal was neither anchored to scriptural exegesis (objective interpretation) nor to scriptural eisegesis (subjective interpretation). It came about by a direct realization that caught a glimpse of pure Mind (cittamatra) sufficient to be a lodestar by which to navigate the way to enlightenment.
Not the least important, the Sutra that Bodhidharma expounded from to his small band of disciples, viz., the Lankavatara Sutra, placed a great deal of emphasis on self-realization (pratyatmaryajnana). In Gunabhadra’s translation of the Lanakvatara Sutra proof of such emphasis is found in this passage:
“Siddhanta [realization] and principle and also self realization [praty-atman] and instruction—those who see the distinction do not come under the sway of deduction [exegesis]” (T 16, p. 499c).
Zen, beginning with Bodhidharma, tried to emphasize realization but later, eventually jumped out of the proverbial frying pan into the fire with its urban legend of a teacher to student transmission beginning with Mahakashyapa. It hardly meets the test of reason or ordinary common sense to take a position of representing a teaching outside of the canon then, oddly, rely on a dubious teacher to student transmission based on nothing either inside the canon or even outside of it.
Still, Zen is to be given credit for putting spiritual insight (siddhanta) above scriptural exegesis and eisegesis. Where it shamefully neglects this arrangement, it is to be condemned. One of the most egregious examples that comes to mind would have to be Dogen’s supposed transmission document (J., shisho) which he allegedly received in China from his teacher Ju-ching which later proved to be a medieval forgery.
For modern Zen, its alpha & omega should be a realization which comes from outside the institution. Not only is Zen a realization which necessarily transcends scripture but, consistently, it must also transcend the Buddhist institution, itself, which often is spiritually dead. This kind of institutional transcendence might be illustrated using the example of the Samurai’s path of a shugyosha which was followed by the Japanese warrior-saint Miyamoto Musashi. William Scott Wilson in his book, The Lone Samurai, describes a shugyosha’s life beautifully, and I think in a Zen way.
“His belongings were few: the clothes on his back, perhaps a small sewing kit, a bamboo canteen, at the very most a very small amount of pocket money, and ink stick and writing brush, and, of course, his sword. As he walked over the stony mountain paths, he wore a pair of straw sandals that would quite often need repairing or replacing. If he was lucky, he might find a straw hat for his head. There was unlikely to be anywhere to stop for food when he was hungry, or a pleasant place to lie down when he was tired. For those who believed in folktales, the dark mountains were filled with foxes and tanuki (a sort of badger), both experts at bewitching the unsuspecting. For those who did not believe such tales, there was still the very real danger of bandits.”
For a modern day Zen shugyosha in which the goal is the realization of pure Mind, backpacking into the ‘dark mountains’ would be quite a noble undertaking. As for one’s sword, only a walking staff would be necessary by which to ford mountain streams (yes, I've done this in my younger days). Also, the Lanakavatara Sutra and a few other texts might be of help for the aspiring Zen shugyosha.
It is only by this kind of course, that is, becoming a latter-day shugyosha, that the real mind-seal is eventually realized. By the noble intention of seeking the mind-seal that is beyond letters and words; which is also beyond the four walls of an institution, one is surely preparing the soil to receive the mysterious seed of the Bodhi-tree.