The Northern School of Ch'an has made remarkable contributions to Buddhism from its origin in China to its spread to Japan and Central Asia.  Although it is no longer a living tradition, it has made an immense contribution to Buddhist thought.  This paper will briefly evaluate the origin of the Northern School in China, it's fight with the Southern School of Ch'an and its subsequent diffusion to the only other country in which it spread, Tibet.  In Tibet we will briefly explore the Ch'an foundation prior to Northern Ch'an's arrival,  Northern Ch'an's initial success, and Northern Ch'an's subsequent debate against the Indian Buddhists at bSam Yas.  We will conclude with an evaluation of Northern Ch'an's contribution to Tibetan and Central Asian Buddhism.
            A discussion of Northern Ch'an in Tibet would be impossible  without an analysis of it's birth and development in China.  The historical accounts of Ch'an in China demonstrate an unusual, and vitally important period of Buddhist philosophical maturation.  This period resulted from a single idea from the 5th Chinese Ch'an Patriarch, Hung-jen, and was followed by what could be called the "Golden Age" of Ch'an development.  To adequately discuss this we need to first explain how Hung-jen planted this seed, followed by his creative successors who expanded on his teachings.  Then we need to discuss Shen-hui, the man who attempted to re-write history by fabricating stories and attempting to re-create the lineage itself.  Finally, the aftermath of this attack and the ushering in of the new age of Ch'an will give us a greater perspective of how Northern Ch'an spread to Tibet and how it interacted with Tibetan Buddhism.
            Ch'an developed slowly in its first 100 years in China.  According to the official Ch'an lineage proposed by both the Northern and Southern schools: Bodhidharma taught Hui-k'o, Hui-k'o taught Seng-ts'ang and Seng-ts'ang taught Tao-hsin.  Ch'an began to blossom creatively with the creation of a new style of teaching, created by Tao-hsin and carried on by his successors.  This style of monastic Ch'an continues to the present day and is summed up in a list of rules known as the "pure regulations".
            The "pure regulations" include four major points of practice that set the Ch'an community apart from other sects of Buddhism.1 These points include:
1.Scriptures were to be studied for their deeper spiritual meaning and not to be taken literally.
2.Ch'an was a spiritual practice for everyone.
3.Activity of any kind is meditation.
4.The community is independent -- creating its own resources, such as growing food.
Although some scholars debate whether the "pure regulations" originated in this period, these trends become very noticeable in the Ch'an stories and documents of the 6th and 7th century.2
            With Ch'an practice codified and carried out, and the emergence of the unified and stable T'ang dynasty, the next generations of students were given a platform on which to base their own ideas and teachings.
            During the period of Tao-hsin's lifetime, the argument about sudden versus gradual enlightenment emerged.  Although Tao-hsin was a proponent of gradual enlightenment, later generations continued to debate and new schools began to emerge based on doctrinal differences.3  Tao-hsin's position is summed up in his work Five Gates of Tao-hsin:

Let it be known: Buddha is the mind.  Outside of the mind there is no Buddha.  In short, this includes the following five things:
First: The ground of the mind is essentially one with the Buddha.
Second: The movement of the mind brings forth the treasure of the Dharma.  The mind moves yet is ever quiet; it becomes turbid and yet remains such as it is.
Third: The mind is awake and never ceasing; the awakened mind is always present; the Dharma of awakened mind is without specific form.
Fourth: The body is always empty and quiet; both within and without, it is one and the same; the body is located in the Dharma world, yet is unfettered.
Fifth: Maintaining unity without going astray -- dwelling at once in movement and rest, one can see the Buddha nature clearly and enter the gate of samadhi.4

Tao-hsin had two students of prominence: Fa-jung, who started what is now known as the Oxhead School and his successor Hung-jen. Reports of Hung-jen, the fifth Chinese patriarch of Ch'an, show a history similar to the first four patriarchs.  He left home early to become a monk, sat for long periods of time in meditation, discarded the sutras, realized enlightenment, and died at an advanced age after transmitting his teachings to a single successor.5
            Hung-jen marks the beginning of a new period of Ch'an, one characterized by strong master-disciple relationships and the expanding of spiritual practice beyond the Indian dhyana meditations.6   Hung-jen's spiritual practice was based on the Indian teaching of "gradual enlightenment," taught by his predecessor, Tao-hsin.
            In this period of expansion of Ch'an practice, Hung-jen had as many as eleven students who he confirmed as mastering the teachings.  Even more incredible than this, three of these students, Shen-hsiu, Hui-neng and Chih-hsien started their own schools based on variations of Hung-jen's teachings.7
            However, according to some Ch'an documents, the tradition of choosing a dharma heir continued, and Hung-jen's heir was a brilliant student named Fa-ju.  However, Fa-ju was never included in the list of patriarchs, and at the time, a formal theory of a patriarchal lineage had not been established.  Despite the succession of Fa-ju, the official heir to Hung-jen, according to the reliable Confucian scholar Ch'ang Yueh (667-730), is Shen-hsiu.8
            Before we look at Shen-hsiu, we should first look at the teacher who modern day Zen schools consider the sixth patriarch, Hui-neng.  It is almost impossible to separate fact from fiction in the case of Hui-neng.  Very little is known about him and nearly everything that is known comes from the Platform Sutra, a work that has been historically invalidated in recent years.  We do know that Hui-neng was a younger contemporary to Shen-hsiu who led the typical mundane life of the Ch'an teacher as was discussed in the section on Hung-jen.9   As for Hui-neng's actual teachings, it is believed that they were no different from those of Shen-hsiu.  In fact, as John McRae discovered in his research: "Ch'eng-kuan of the Hua-yen school, for example, was unable to see any significant difference between the teachings of Northern (Shen-hsiu's) and Southern (Hui-neng's) Ch'an."10  For example, the arguments over sudden versus gradual enlightenment were not Hui-neng's ideas, but are thought to have been created by one of Hui-neng's successors, Shen-hui, who will be discussed later.
            Shen-hsiu was a very famous, highly educated teacher who attempted, like Hui-neng, to emulate the teachings of his late master.11  Shen-hsiu moved to Lo-yang, the capitol, in 701.  He was accepted by the Emperor and Empress and even tailored his teachings to fit their needs.   Shen-hsiu named his school the "East Mountain Teaching" in honor of his teacher Hung-jen, who taught on what was known as the East Mountain.
            Up to this time, there was no reference to Northern or Southern schools and there was little or no conflict between methods of spiritual practice.  This harmonious period between the time of Hung-jen and the deaths of Shen-hsiu and Hui-neng was the most creative period of Ch'an.  However, this broad range of creativity inevitably resulted in conflict.  As Heinrich Dumoulin points out: "The rich diversity of spiritual and intellectual elements that flowed together during this early period of Zen Buddhism were the harbinger of conflicts to appear in the following two or three generations."12  These conflicts began with the dubious claims of a monk named Shen-hui.
            It is with Shen-hui and his successors that the colorful legends of Ch'an are created and developed.  Before Shen-hui, there had been no Northern and Southern schools, gradual or sudden enlightenment, or even a conflict over lineage.  
            Shen-hui was a monk from Nan-yang who was determined to start his own school of Ch'an.13   He was born in 684 and in his early 20's studied with Hui-neng for about seven years, until Hui-neng's death in 713.14  In 732, Shen-hui held a conference in Hua-t'ai at the Ta-yun Temple.  Here he planned his attack against the school of Shen-hsiu which included referring to Shen-hsiu's school as the Northern School, substituting Shen-hsiu for Hui-neng in the lineage, attacking Shen-hsiu's school on doctrinal points and once his attack was successful, declaring himself Hui-neng's successor.15
            Shen-hui's first line of attack was to create a broader difference between the schools of Hui-neng and Shen-hsiu.  He did this by labeling Shen-hsiu's teachings "The Northern School", an attack that implied that Shen-hsiu's school was based on inferior teachings.  Before this attack, as was mentioned earlier, Shen-hsiu referred to his school as "The East Mountain Teaching".16  Shen-hsiu's disciples later referred to their school as the "Southern School".  This controversy over what is the Northern School and what is the Southern School is based both on geography (the "Northern School" was in the North) and the Chinese saying nan-tun pei-chien, meaning "suddenness of the South, gradualness of the North".17 
            At the time in China, sudden enlightenment was considered the true teaching, and everyone identified their school with the practice of sudden enlightenment.  Therefore, for Shen-hui to label Shen-hsiu's school "The Northern School" is an insult, implying that Shen-hsiu's school had inferior teachings.  It would be similar to referring to Theravadan Buddhism as Hinayana.18  Heinrich Dumoulin writes:  "According to the mainstream of later Zen, not only is sudden enlightenment incomparably superior to gradual enlightenment but it represents true Zen -- indeed, it is the very touchstone of authentic Zen."19   Of course, Shen Hui was not the first to argue over sudden versus gradual enlightenment.  The fifth century teachers Hsieh Ling-yun (385-433), Seng-chao (374-414) and Tao-sheng (360-434) argued the same position, sometimes even using Taoist terminology and sources.20
            Shen-hui's substitution of Hui-neng as the real dharma heir involves a series of fabricated stories and teachings, including re-writing the lineage, and attempting to prove that Hung-jen intended for Hui-neng to be his successor. 
            Shen-hui first makes his point by saying that from the time of Bodhidharma, each master has given his robes to his successor.  This line of succession continues all the way down to Hung-jen, who, according to Shen-hui, gave his robes to Hui-neng.21  Shen-hui wrote:

The robe is proof of the Dharma, and the Dharma is the doctrine (confirmed by the possession) of the robe.  Both Dharma and robe are passed on through each other.  There is no other transmission.  Without the robe, the Dharma cannot be spread, and without the Dharma, the robe cannot be obtained.22

            Up to this point, the idea of a singular line of succession did not exist.  In fact, when Shen-hui first told this story at the conference in Hua-t'ai, a representative from Shen-hsiu's lineage expressed puzzlement:  "Confused, Ch'ung-yuan asked why there could be only one succession in each generation and whether the transmission of the Dharma was dependent on the transmission of the robe."23  As most lies tend to be, this one required additional supporting lies to make it stand on its own. 
            To legitimize these fabricated stories, Shen-hui created another story to complement them.  In this story, Shen-hui creates a fictional dialogue that he uses in his teachings:  "During his lifetime the Ch'an Master Shen-hsiu stated that the robe, symbolic of the Dharma, as transferred in the sixth generation, was at Shao-chou (near Hui-neng's temple)."24
            The most important fabricated story is probably the dialogue that takes place between Shen-hsiu and the Empress Wu.  Philip Yampolsky describes this story from one of Shen-hui's texts called Nan-yang ho-shang wen-ta tsa-cheng i:
...when the Empress Wu invited Shen-hsiu to court, in the year 700 or 701, this learned priest is alleged to have said that in Shao-chou there was a great master [Hui-neng], who had in secret inherited the Dharma of the Fifth Patriarch.25 
This story appears in almost every account of Ch'an in this period, including the Sutra of the Sixth Patriarch, which will be discussed later.
            Shen-hui then attacks "The Northern School" on doctrinal differences.  Again, these attacks are fabricated.  Shen-hui claims, as was mentioned in his labeling of Shen-hsiu's teachings, "the Northern School", that the Northern School practices gradual enlightenment.  To back up this claim, he uses several fabricated dialogues similar to the ones he used in his robe claims.  The most famous one is a dialogue between Master Yuan and Shen-hui about two of Shen-hsiu's successors, P'u-chi and Hsiang-mo:

            The Master Yuan said: "P'u-chi chan shih of Sung-yueh and Hsiang-mo of Tung-shan, these two priests of great virtue, teach men to "concentrate the mind to enter dhyana, to settle the mind to see purity, to stimulate the mind to illuminate the external, to control the mind to demonstrate the internal."  On this they base their teaching.  Why, when you talk about Ch'an, don't you teach men these things?  What is sitting in meditation (tso-ch'an)?"
            The priest [Shen-hui] said: "If I taught people to do these things, it would be a hindrance to attaining enlightenment.  The sitting (tso) I'm talking about means not to give rise to thoughts.  The meditation (ch'an) I'm talking about is to see the original nature."26 

This assault was Shen-hui's best shot against the Northern School.  As Philip Yampolsky writes: "This attack was clever and effective; it may, however, have been quite unjustified."27  The Northern School also taught a form of sudden enlightenment.  It's teachings were a sophisticated blend of practices derived from the Heart Sutra, the Lankavatara Sutra and the teachings of Hua-Yen.  As Philip Yampolsky points out, it may have been closer to the teachings of Hung-jen than what Shen-hui promoted.28
            These descriptions of Shen-hui's attacks might sound as if there was a pitched battle between the Northern School and the Southern School.  This was not the case.  The "Northern School", as it is known today, ignored Shen-hui.  There is not a single reference to Shen-hui in any Northern School text. As John McRae points out, "This failure to rebut Shen-hui's criticism is indicative of the fictitious nature of the entity `Northern School.'"29  Even if these attacks failed, however, it gave Shen-hui's school much needed attention.  If it had not been for Shen-hui's attack, which drew attention to the school of Hui-neng, Hui-neng's school probably would have drifted into obscurity.30
            The down side to this for Shen-hui, was that his outspoken attacks attracted the attention of the imperial censor, Lu I, who was in favor of the Northern School.  After an interview with Emperor Hsuan-tsung in 753, government officials were convinced that Shen-hui was a dangerous person, and therefore banished him from the capitol, Lo-yang.31
            Shen-hui was sent to various places during his exile, all of which were strongholds of Northern School teachings.  He used this situation to his advantage, preaching and gaining increasing influence through his attacks.  The government which banished Shen-hui was driven into exile in 756, when a rebel army took the capital cities in the An Lu-Shan Rebellion.  Forced to defend themselves from this attack, the government began fund-raising efforts to support their armies, which included setting up ordination platforms to sell certificates of ordination.  Shen-hui was brought back from exile to help in these efforts.32  In return for his service, the government promised him a position of authority and power.  Heinrich Dumoulin responds to this by saying:
It seems ironic that one who so relentlessly criticized masters of the Northern School for carelessly assuming honorific titles and so betraying the true spirit of Bodhidharma should spend his old age basking in the grace of the powers that be.33
Shen Hui's school, fostered by the government, became the predominant school of Ch'an.  By being so close to the imperial court, Northern Ch'an had become the "fashionable" religion of the day.  However, it was during this period that China was invaded by Tibet and lost the city of Tun-Huang, creating a new interest in Ch'an from the Tibetan court.  Northern Ch'an, although appearing on the scene in Tibet later than other schools, had a major influence in the Tibetan Buddhist panorama.
            The first spread of Ch'an to Tibet came in 761 (dates vary) when the King K'ri-sron-lde-bstan sent a party to I-chou to receive Ch'an teachings.  According to the chronicle, Statements of the Sba Family, the party received teachings and three Chinese texts from the Korean Ch'an master, Reverend Kim (Chin ho-shang), supposedly known as the most famous Ch'an master in China, who they met in Szechwan.34  Unfortunately Reverend Kim died later that same year.  A second party was sent to China in 763, led by another member of the Sba family, Gsal-snan.  There is debate about who Gsal-snan encountered when visiting I-chou.  Some scholars thought that Gsal-snan met with Reverend Kim, but with strong evidence of Kim's death in 761, they now believe he met with Pao-t'ang Wu-chu (714-774), head of the Pao-t'ang Monastery, and a possible successor to Reverend Kim.35  Nevertheless, the teachings of Reverend Kim and Wu-chu laid the foundation for the Northern schools arrival.
            While the Northern school was in the midst of decline following the attacks of Shen-hui, a Ch'an master named Hva-shang Mahayana took advantage of the political situation and travelled to Tibetan-occupied Tun-huang (781 or 787).36  Tun-huang was a significant hub in the spread of Buddhism between China, Tibet, Central Asia and India, and Tibet had recently wrestled it away from Chinese forces.  For example, Buddhist scholar Luis Gomez calls Tun-huang "the crossroads of Buddhism on the Sino-Tibetan Central Asian frontier."37  For Hva-shang Mahayana, a new door had been opened for the spread of (Northern) Ch'an Buddhism.    
            Hva Shan was a third generation heir to Shen-hsiu, having been taught by several of Shen-hsiu's students.  Although it is not clear what exactly Hva Shan Mahayana did in Tun-huang, we do know, according to the Tun-huang text Settling the Correct Principle of Suddenly Awakening to the Great Vehicle (Tun-wu ta-ch'eng cheng-li chueh), that the King K'ri-sron-lde-bstan invited him to Lhasa.38  This invitation was not an unusual occurrence, considering that Ch'an had been in Tibet for years before Hva Shan's arrival and that the king had been interested in learning about different Buddhist schools.
            Mahayana gained a fairly large following of students in his short stay in Lhasa, mostly because of his close ties to Ch'an master Tao-t'ang who was already well established as a teacher.39 This, however, was probably the final blow against the Indian Buddhists who, threatened by the Chinese Buddhist influence, brought political repercussions  against the Chinese masters.  Indian Buddhist teachers were concerned with the incredible popularity of Chinese Buddhism and its winning over of Tibetans. 
            Power, wealth and international relations were at stake in the vying for political patronage.  According to R.A. Stein, "Its [Chinese Buddhism] popularity worried the Indian teachers, who had chiefly preached simple rules of moral conduct and the principle that good or bad actions are rewarded in future life."40  Similar to the position in China of Shen-hsiu silently being attacked with unfounded claims by Shen-hui, Hva Shan Mahayana probably did not recognize the Indian threat or the possible long-term repercussions of this brewing conflict.
           King K'ri-sron-lde-btsan was son of Sron-btsan-sgam-po who was the first patron of Buddhism in Tibet.    Concerned with perpetuation of proper religious doctrine as well as other possible political motives, following in his fathers tradition of Buddhist patronage and the supervision of Tibet's "spiritual" welfare, he decided to stage a debate at the bSam yas Monastery to determine which doctrine should be officially patronized.41
            Far from being overly concerned with "correct" religious practice, it appears that the king had his own political agenda in mind.  In his article on the debate, Joseph Roccasalvo quotes Paul Demieville's belief:

       
That a sinophobic party had existed at the court of Tibet, and that it had backed the Buddhists of India, less suspicious of political compromises, nothing [is] more likely, especially since the rapport between China and Tibet was particularly strained at the end of the eighth century.  Across all her history, since her origins up to our present day, Tibet has been tossed between China and India; its politics have always tended to safeguard national independence by playing these powers, one against the other...42

This belief that politics played an important role in the events surrounding the debate is a popular and sound theory, also held by Giuseppe Tucci.  Tucci also brings the issue of growth of the monastic community as a reason for the debate.  As the Buddhist community grew, the government grew less powerful due to the increased economic power of the monasteries.43  The debate played the role of protecting the state and limiting the power and wealth of the Buddhist community by disqualifying the loser from royal patronage and huge donations.
            The details of the actual debate is open for much scholarly analysis -- especially opinions regarding the number of debates as well as the content.  Buddhist scholars such as Tucci question the idea that a debate took place, while others such as Tanaka and Robertson and Ueyama believes that multiple debates were held.44  The remaining scholars are placed somewhere in the middle, acknowledging the existence of the debate but accepting the predominant theory that only one debate took place.  I tend to side with Tanaka and Robertson with the number of debates.   The content and outcome of the debate(s) is more complicated.
            Excluding the political motives for the debate, the main doctrinal conflict was between the gradual enlightenment position of the Indian school and the sudden enlightenment position of the Ch'an school.  Hva Shan Mahayana took on the role of ston-mun-pa, or "representative" of the Ch'an school, while the fairly unknown Indian master, Kamalasila, represented the Indian school.  It has also been noted that K'ri-sron-lde-btsan did not play a significant role in the debate, probably because of his lack of "doctrinal preparation."45
            The doctrines of sudden versus gradual enlightenment were not a new debate, as we have seen from the Northern Ch'an's experiences in China.  Joseph Roccasalvo quotes Helmut Hoffman's analysis of the two opposing positions:

The most important matters of doctrine in which Hva-shang differed from his Indian rival were (1) the attainment of Buddhaship does not take place slowly as a result of a protracted and onerous moral struggle for understanding, but suddenly and intuitively -- an idea which is characteristic of the Chinese Ch'an and of the Japanese Zen sect which derives from it; (2) meritorious actions whether of word or deed, and, indeed, any spiritual striving, is evil; on the contrary, one must relieve one's mind of all deliberate thought and abandon oneself to complete inactivity.46

            Kamalasila's position was that enlightenment was a gradual process that required moral purification through proper practice.  Enlightenment was not guaranteed to the individual in the present lifetime, but was to be continued throughout a series of many lifetimes until one was purified.  This purification process was accomplished by the complicated practice of Yogacara meditation techniques.  The idea that enlightenment could not only come in one lifetime, but came only after a practitioner could "abandon oneself to complete inactivity," was "heretical" to Indian teachers like Kamalasila.47  Jeffrey Broughton explains how the Indian school would have perceived the teachings of Northern Ch'an: " Under such conditions it is unlikely that the Indian pandits would have had much patience for the ston mun's "gazing-at-mind," a Ch'an meditation with antecedents in the East Mountain Dharma Gate and their earliest Northern Ch'an teachings, and "no-examining." For them, "no-examining" only came after effortful examining or analysis."48       
            The outcome of the debate is unclear.  Chinese sources claim Mahayana the winner, while Tibetan sources claim Kamalasila as the victor.49  A Tibetan source cited by Tucci from rNying-ma rDzogs-chen literature also claim the Ch'an school the winner; however, Tanaka and Robertson refute this source on the basis of its historical inauthenticity.50  Regardless of who won the debate, it is clear that Indian Buddhism became the predominant practice in Tibet following the councils.
            The debate was characterized by prejudice and misunderstanding on both sides. In addition to the political barriers and concerns, there was also a significant language barrier. Neither side spoke each others language, and Tibetan was probably used as a middle ground in the debate.51  Both sides probably understood the other position from previous information gained from "hearsay," and as Jeffrey Broughton points out, "...even hearsay had to pass through a formidable language barrier."52  I would argue that although the Northern Ch'an school might not have had a firm grasp of specifics of Indian doctrine, it should have had a strong understanding of the gradual approach from having to defend itself from Southern School attacks in China.
            The aftermath of the debate is as complicated as the debate itself.  There were many bizarre stories surrounding the results of the debate.  One interesting legend is that Ch'an practitioners, extremely upset at the defeat of Mahayana, "sent four Chinese thugs who disposed of the defenseless Kamalasila by 'squeezing his kidneys.'"53  This idea that Ch'an was defeated in complete disgrace and forced to leave Tibet is more myth than reality.  Hva Shan Mahayana was not devastated by his defeat as some Tibetan sources would have us believe, nor was he forced to leave Tibet.  He was content in his teaching and understanding, especially in strong belief that "gradual enlightenment is a metaphysical impossibility."  Similar to Shen-hsiu's position with the Southern School, Mahayana did not realize the long term results of the debate.  Mahayana later wrote several memorials to the king, one of which says: 

Never have I, Mahayana, been lacking, when one of my disciples whom I am teaching comes to interrogate me concerning my views and interpretations.  Never do I fail to teach him the field of merits which is giving (dana), and to get him to take a vow of abandon...his body, his head, his eyes, and every necessity except the eighteen things the Great Vehicle permits.54 

            The fate of the Chinese Ch'an schools following the debate is very confused.  According to R.A. Stein, the Chinese were kicked out of Tibet "in no gentle fashion."55  In reality, it is much more complicated.  Ch'an continued in Tibet for many years following the debate at bSam yas.  In fact, the attention given to the Northern School peaked the interests of Tibetans even more, thus perpetuating the practice of Ch'an and Chinese approaches for many years afterwards, but without the political and social trappings that Ch'an had been accustomed to.
            Also, it is believed that the popularity of Ch'an resulted in its spread beyond the borders of Tibet into Central Asia.  John McRae is a strong proponent of the idea that the influence of Northern Ch'an was not restricted to Tibet.  For example, Northern Ch'an texts were translated into many Central Asian languages, including Hsi-hsia and Uighur.56
            Northern Ch'an also may have played an important role in influencing Tibetan philosophy outside of the Ch'an tradition.  According to Tucci, Ch'an may have played an influential role in shaping rDzog-Chen philosophy.  However, he bases his claims on sections of the BLon-po and bKa'thang sde-lnga, a rNying-ma/rDzogs-chen document from the 14th Century.  However, Tanaka and Robertson question the historical authenticity of this document also.  Tanaka and Robertson argue that  "...the Bsam-gtan by gNubs-chen Sangs-rgyas ye-shes (772-892), a major Rdzogs-chen figure, shows clearly that Ch'an and Rdzogs-chen must be considered doctrinally distinct traditions."57  Samten Gyaltsen Karmay agrees with this interpretation.  He writes:
One might get the impression that this work [the sBas pa'i rgum chung] contains certain ideas that are parallel to those of the school of the simultaneous path (cig car 'jug pa'i lugs).  However, it would perhaps be too naive to assume that once mention is made of mi rtgo pa, it is "influenced by the Ch'an school".... On the other hand, there are certain elements which have no parallel in the Ch'an school.  It is undeniable that mi rtgo pa is taken as the central dogma of the Ch'an school, but it has always been the most important aspect of Buddhist contemplation in general.58
Even if Ch'an did not directly influence rDzogs-chen thought, its philosophy was at least preserved in Tibetan documents as an example of improper practice, thus at least preserving the philosophy as a negative example.
            It is ironic that Northern Ch'an could lose two separate debates regarding the issue of sudden or gradual enlightenment.  Northern Ch'an lost its position in China after Shen-hui claimed that they practiced the "dreaded" gradual enlightenment approach.  Then, in Tibet, Northern Ch'an faced the same fate after being accused of the "dreaded" sudden enlightenment approach.  It seems that the suddenness or gradualness of enlightenment had very little to do with either of these debates.  They were both lost due to the inability of the Northern School, represented by two different teachers, to realize and correctly interpret the political climate and potential outcome surrounding these doctrinal debates.  Each debate is characterized by a poor evaluation of political support and an unhealthy proximity to government officials and state patronage. 
            The integrity, sincerity and intelligence of the individuals involved has never been an issue.  Joseph Roccasalvo points out about Hva Shan Mahayana,
"...we have encountered a man of deep interiority, whose "passion" for the truth and whose respect for transcendence have led him to ever more subtle levels of expression and paradox, but who knows down deep (like Gotama before him) that the real truth "is only transmitted and conferred by silence."
Unfortunately, the politics of religion usually have very little to do with sincerity and truth.  Arguably, the most important teaching to come from the Northern School, and passed to later teachers in China and Japan, was the avoidance of centers of political power.  The founder of the Soto school in Japan, Do-gen Kigen, was warned by his Chinese teacher Ju-ching:

You should not live in cities or other places of human habitation.  Rather, staying clear of kings and ministers, make your home in deep mountains and remote valleys, transmitting the essence of Zen Buddhism forever, if even only to a single true Bodhiseeker.59

Works Cited
            Dumoulin, Heinrich.  Zen Buddhism: A History, Vol 1.  New York: Macmillan Publishing Company, 1988.
            Gimello, Robert M. and Peter N. Gregory, Ed.  Jeffrey Broughton.  "Early Ch'an Schools in Tibet."  Studies in Ch'an and Hua-yen, Studies in East Asian Buddhism, no. 1.  Honolulu: University of Hawaii Press, 1983.
            Goodman, Steven D. and Ronald M. Davidson, Ed.  Kenneth K. Tanaka and Raymond E. Robertson.  "A Ch'an Text from Tun-huang: Implications for Ch'an Influence on Tibetan Buddhism."  Tibetan Buddhism: Reason and Revelation.  Albany: State University of New York Press, 1992.
            Gregory, Peter N., Ed.  John R. McRae.  "Shen-hui and the Teaching of Sudden Enlightenment in Early Ch'an Buddhism."  Sudden and Gradual.  Studies in East Asian Buddhism, no. 5.  Honolulu: University of Hawaii Press, 1987.
            Gregory, Peter N., Ed.  R.A. Stein.  "Sudden Illumination or Simultaneous Comprehension: Remarks on Chinese and Tibetan Terminology."  Sudden and Gradual.  Studies in East Asian Buddhism, no. 5.  Honolulu: University of Hawaii Press, 1987.
            Karmay, Samten Gyaltsen.  The Great Perfection (rDzogs Chen).  Leiden, THE NETHERLANDS: E.J. Brill, 1988.
            Lai, Whalen and Lewis R. Lancaster, Ed.  Luis O. Gomez.  "Indian Materials on the Doctrine of Sudden Enlightenment."  Early Ch'an in China and Tibet.  Berkeley Buddhist Studies Series, no. 5.  Berkeley: Asian Humanities Press, 1983.
            McRae, John R.  The Northern School and the Formation of Early Ch'an Buddhism.  Studies in East Asian Buddhism, no. 3.  Honolulu: University of Hawaii Press, 1986.
            Roccasalvo, Joseph F.  "The Debate at bSam yas: A Study in Religious Contrast and Correspondence."  Philosophy East and West. December, 1980.
            Samuel, Geoffrey, Trans.  Giuseppe Tucci.  The Religions of Tibet.  Berkeley: The University of California Press, 1988.
            Stein, R.A.  Tibetan Civilization.  Stanford: Stanford University Press, 1972.
            Yampolsky, Philip B., Trans.  The Platform Sutra of the Sixth Patriarch.  New York: Columbia University Press, 1967.
            Yokoi, Yuho.  Zen Master Dogen.  New York: Weatherhill, 1987.