What follows is based on my notes from that later teaching on the Seven Line Prayer of Guru Rinpoche. For those of you who know who Rinpoche is (in my mind, he is very much with us) or who know Guru Rinpoche Padmasambhava, no introductions are needed. However, by way of preamble, a couple of introductory notes about both worthies may be in order for others.
There is a wealth of narratives regarding Padmasambhava's life and a similar amount of study and exegesis on his teachings and the termas attributed to him. Briefly, excluding the miraculous or fabulist elements of his life, Padmasambhava (the One Born from Lotus) was a pandit who taught at Nalanda, who may have hailed from what is now Pakistan or Afghanistan, who was requested to come to Tibet by the great abbot Shankarakshita to dispel malignant forces and obstacles to the establishment of late Indic Buddhism in Tibet during the dynastic period, and who built Samye monastery.
As with many great figures in religious history, there is scant, or no primary contemporary sources to support the historicity of Padmasambhava. That said, there are some telling clues that point to a master of some sort who at the very least, played a pivotal part in Tibet's history and the founding and nurturing of Buddhism in the region. This is not the space nor the time to go into as great a detail as I'd like, but he's one of the towering figures - not just in Tibetan history - but in overall religious study. Or at least, should be. To get a little wonky here, in the works attributed to him, and in much of the Nyingma teachings that survive from earlier sources and periods we decry strains of Indo-Iranian origin, Zoroastrianism, Manichaism, as well as mythic overlays and details similar to virgin birth myths across the Middle East. All this is subsumed and absorbed into some remarkable works and it's difficult to not want to ascribe this to a powerful, charismatic individual.
Lastly, the Padmasambhava narrative also introduces one of the great women figures in Tibetan history, someone else who should be further explored in comparative studies and brought more forward. His main pupil and consort Yeshe Tsogyal's story is itself one of the most moving ever told. It's telling that the first Tibetan person to achieve enlightenment is a woman. I'll leave this aside but recommend further exploration to whomever reads this.
The Seven Line Prayer of Padmasambhava doesn't enter usage in Tibetan teaching or literature until well after Padmasambhava's passing and the end of the Yarlung dynasty. It derives from a terma and has since grown to a cultural institution on the order of the Mani mantra (the familiar "om mani padma hum" mantra of Avalokiteshvara/Chenrezig); it is also multivalvent and serves as a medium for meditation on all stages of the path, as Rinpoche's teaching will make more plain in the following.
Lama himself was a remarkable person. I'm linking to the Vajrayana Foundation which has a great collection of his teachings and a short biography of Rinpoche. Personally, he's one of those jewels of humanity that I wish I had spent more time with and could have learned more directly from. He struck me as one of the gentlest, most self-deprecating teachers I've ever had the privilege of listening to. His self-effacement covered up a depth and breadth of learning and practice probably equalled by only the most accomplished. Additionally, I kept hearing in India how much he held in the way of knowledge of Tibetan folklore and the arts. While I was in India, Dungse Thinley Norbu had passed (another heart son of Dudjom Rinpoche and you could say, I think, brother to Lama Tharchin without too much exaggeration); I was in Bodhgaya while the paranirvana rituals were going on and this led to much reflection on how this generation is passing and how we best avail ourselves of these elders, learn as much as we can, and emulate their kindness and wisdom as much as we can.
Sadly, Lama Tharchin left this existence in July of 2013. I wasn't able to see him again, but what I heard from him was like coming home. In what follows, cobbled together from notes that I've come back to over the past couple of years, is what I hope is some kind of distillation of the vastness of these teachings. Rinpoche's talks carried so much more that was implicit, folded into a small amount of time; as with the best teachers, what they said takes root and opens up over a period of time. I know some people will read this and think, "well, I've read this elsewhere" or "oh, I've heard this before". We miss out then, through our pride. We miss that we're supposed to make these words come alive in us. We miss the humility that we, frankly, need to be reminded of what really is, why we continue to live lives we hope are beneficial for all, as conscious and aware and as loving as possible.
What follows are notes of what was just one day from which I've drawn inspiration to continue studying, meditating, and hopefully, growing in a way that will aid others. They are being offered in that spirit.
I'll add notes where some clarification may be of assistance. I don't expect non-Tibetan Buddhists and others to be conversant with all points. There's a fair amount of "technical terms" within any given tradition. When we are discussing translation/transplanting from other cultures and languages, it's important to have a sense of context and nuance. I'll do my best.
Bear in mind that I'm adapting this from notes and notes mean...well, "notes". These are phrases, sketches made on the fly. I'll be working the phrases into sentences, so the ideas may have a sense of closure as opposed to the openness that a collection of fragments would have. I'll be paring down ambiguity, but at the same time, the choice of words may enclose the meaning of those phrases in such a way that it may seem to limit interpretation.
I think all will be well; I believe the substance of Lama Tharchin's teaching will be preserved here. Sadly, I can't convey his presence, his humor, or the unspoken aspects of who he is. I'll be happy, however, if I can get some of the richness of this across.
That said, I have to start out of the gate with a note. Lama Tharchin began his talk with Guru Rinpoche as the Nirmanakaya who "taught in human language." This alludes to the trikaya/triple body interpretation of existence. This is a trinity of the dharmakaya, the sambhogakaya and the nirmanakaya, often interpreted as three levels of being, but it's a little subtler than that.
The graded stages of the path indicate that these are three different forms of being but ultimately are subsumed or recognized as simultaneously existing upon enlightenment. I think a better way of approaching it is that these are three points of view or interpretation of different points/folds of existence as we experience it.
In later Indian Buddhism that was carried over into Tibet, a schema was developed whereby the relative dimensions of the visible world were accounted for as emanations of more refined, less immediately (seemingly) dimensions of existence. Thus, the dharmakaya/chos sku/ཆོས་སྐུ (literally, the "truth body") is the underlying ground of emptiness/appearance in the later developments of Indo-Tibetan Buddhism. I would be chary of translating dharmakaya or chos-sku as "the Absolute" as some have done because this forces the issue into accepting a kind of Hegelian metaphysics. Conversely, if that comes predicated with the interpretation that the Absolute is beyond human binary value-schemes and is understood as both immanent and transcendent, then I think it's acceptable. The main point is to understand that the dharmakaya isn't some transcendent reality that has to be attained. It is ever present and before us.
As is the sambhogakaya or the ལོངས སྐུ/longs sku, though this is translated as the "enjoyment body", a kind of fruition of realization that exists outside the mundane experience (I'm thinking of Guenther's reiteration of ecstasy as a state of ex-stasis, standing outside of the present entanglements). But this doesn't convey that this is another fold of reality. However, it does convey that practicing dharma results in "enjoyment", i.e., a fully satisfying experience that the adventitious issue of experience cease to be a source of vexation and that all virtuous actions lead to this sense of satisfaction.
Finally, there is the nirmanakaya/ སྤྲུལ་སྐུ/sprul-sku (pronounced, more or less "tulku" or sometimes "trul-ku") or "transformation body". This is considered the emanation into the physical world that can be perceived by all humans. This last brings up the issue of what we deal with when we encounter semantics and epistemology in Buddhism in general and Tibetan Buddhism more particularly.
A further allusion is that Guru Rinpoche could as easily spoken in the "Dakini language", the language of celestial beings who were often protectors and teachers of Buddhadharma. They are usually embodied as female and one may equate that with the power, strength, and wisdom of the Mother. That said, since Padmasambhava did speak in the human language and we may assume this would have been Tibetan, we'll proceed from there.
Following Guenther and his ilk, it's probably wise to keep in mind that Tibetan is a process-oriented language that doesn't necessarily arrive at lexical content as representative of things-in-the-world as static entities. There is a heavier emphasis on the verb and the connection between states that what would be called in Indo-European languages "subject" and "object". Stephen Hodge's emphasis on adverbial clauses in translating Tibetan is key here. Situations are characterized by flux and change.
Sanskrit tends to be more "object oriented" and like it, most European languages. Linguistically, and psychologically, it may be easiest for us to conceive the three-body schema as a progression from dense matter to finer spirit in the old nineteenth century style metaphysics that still colors much of modern dharma translation from Tibetan. It would also be a mistake. Inasmuch as there are, in most if not all, Asian traditions, the interpretation of consciousness from coarser to finer (and matter along with it), this misses out on the primary ground that appearance arises out of the acceptance of appearance as reality and that praxis, particularly in Tibetan tantrism, dzogchen and mahamudra, is intended to lead to the union of appearance and the energies that give rise to it as an experiential matrix. This is not a metaphysic.
And this is the rub: because this is not a matter of metaphysical hypothesizing, we wind up stymied by asking about its possible interpretation in so-called western philosophical hermeneutics. This isn’t a problem. Hermeneutics is fine, but has dick to do with what’s at issue.
Buddhism is about experience, about being. Sure, there are immense philosophical treatises composed over the centuries, but the end is are you wiser, are you more compassionate? In the west, there are similar traditions couched in Graeco-Hebraic terminology from at least the time of the founding of the early church. The perennial philosophy is never about philosophical terms, it’s about the enlightenment experience itself and how to communicate it and leave word behind about how to work toward it.
It happens that in Tibetan, we have a language that seems predisposed for communicating what happens during those changes. My glancing attempts at classical Chinese tell me that the same holds true which may be why so much of early Chan literature is considered impenetrable. In all these cases, the words become guides to work along the Way, so to speak. Indeed, the words themselves are loaded with a kind of energy that can unpack itself within the individual. Consequently, there is a term, I’m told in Chinese, called "round talking" in which what is said isn’t the only or the full content of what is being said. Implicit in the discussion is that a larger meaning is contained and the act of talking and the act of listening contain much more information than can be contained in the words as communicated.
Now, in Indo-Tibetan Buddhism, we also encounter visual representations in the texts and in other media, as thangkas and paintings and diagrams. Thus, the various buddhas that proliferated in India in the earlier periods of the 1st CE millenium represent most often the sambhogakaya because the dharmakaya is ultimately not subject to r/epresentation on this plane of existence. The nirmanakaya representations are slightly different.
So when Lama Tharchin said that Padmasambhava is viewed as the nirmanakaya because he "taught in human form" and is actually Avalokiteshvara/Chenrezig in the sambhogakaya and Amitabha/O-pag-med in the dharmakaya, the polyvalence of everything I’ve laid out before obtains and is packed into this statement. And more besides.
Using the nirmanakaya as the point of departure, Lama-la recounted the legend of how Guru Rinpoche came to Tibet that it is a variant on what is more often heard. I’ll save the more common narrative for another time; for now, I think Lama’s is pretty sufficient (and cool, if only as one more in the series of oral transmissions of this story!)
Nalanda - what is often regarded as the world’s first university (1) - at the time was in danger of falling apart. As Lama Tharchin said, Buddhist scholars "were pretty weak" and "non-Buddhist scholars were pretty strong" and Nalanda was in danger of being lost to the thirthikas (non-Buddhist pundits).
The Seven Line Prayer came into being at this point when the dakini Shiwa tsog (?) came and noticed the scholars, prior to a great debate, looked a little nervous. "You guys can’t win this debate; you should call my brother." She then taught the prayer to 500 pandits and the rest is, well, history. Perhaps not as we know it, but here’s where we begin.
This was revealed in the gterma (2) discovered by Guru Chowang in the 13th century CE. It’s the main guru practice in the Rinchen Terdzo and the Dojo Bumzang(3). Needless to say, the non-Buddhist philosophers were defeated in the debate and Nalanda continued for several centuries after.
The Seven Line Prayer was also introduced in Tibet when Shankarashita, the former abbot of Nalanda who had been requested to bring the Buddhadharma to Tibet by King Trisong Deutsen was at a loss to deal with the "evil forces" that were presenting obstacles to the founding of Samye monastery. He prayed fervently and the dakinis responded by having him face in the direction of Zhang Zhung and recite the prayer, upon which Guru Rinpoche appeared, subdued the demons and propitiated the teachings of dzogchen.
It was then lost but preserved in the terma discovered by Guru Chowang in either case.
From here, Lama Tharchin pointed out the limitless expanse and variety of Buddha’s teachings. Just as "there is no way to measure how many world systems, Buddha’s view is inconceivable."
Breaking down the Seven Line, we begin with the syllable "Hung." This is wisdom; the singular, original base of the five wisdoms. We can think of Hung as prismatic, differentiating into "the dharmadhatu, mirrorlike, equanimity, discerning, and all-accomplishing wisdom inseparable from Guru Rinpoche’s mind." (See Figure 1.)
Figure 1. The syllable Hung as the Five Wisdoms
"We count five wisdoms [but] Buddha-wisdom is inseparable; Buddhas know only One Mind."
What follows is the outer interpretation of the Seven Line Prayer. While Rinpoche’s exposition follows closely Mipham’s commentary (3), there are some more direct aspects in that Lama Tharchin was perhaps more to the point. Or it could just be that this points out the value of hearing these teachings directly. You can read Mipham’s commentary and "get it", at least, intellectually. But when you hear it from someone’s experience, it carries more weight and perhaps opens something in the heart that the discursive aspect of the human mind misses.
The prayer itself follows in Tibetan script with transliteration and translation from Lotsawa House (http://www.lotsawahouse.org/tibetan-masters/guru-chowang/seven-line-prayer).
hung orgyen yul gyi nubjang tsam
Hūṃ! In the north-west of the land of Oḍḍiyāna
pema gesar dongpo la
In the heart of a lotus flower,
yatsen chok gi ngödrub nyé
Endowed with the most marvellous attainments,
pema jungné shyé su drak
You are renowned as the ‘Lotus Born’,
khor du khandro mangpö kor
Surrounded by many hosts of ḍākinīs
khyé kyi jesu dak drub kyi
Following in your footsteps,
jin gyi lob chir shek su sol
I pray to you: Come, inspire me with your blessing!
guru pema siddhi hung
guru pema siddhi hung
This will help make intelligible what follows.
To jump in, Oddiyana is the place of origin of Dzogchen, nub-chang means "northwest" and mtshams is "border". Guru Rinpoche was born from a lotus on Danakosha lake. Hence, the literalness of his name "Pema Jungne" (Lotus-Born).
Ya-mtsen, etc. notes his marvelous qualities and all else in the above translation accords with Lama Tharchin’s teachings. That said, hearing Lama-la underscore the importance of the lines "khye-kyi je-su dag-drub kyi" etc. as "motivation to follow in Guru Rinpoche’s footsteps" added an emphasis to the prayer that you’re not going to get from reading it and nodding one’s head.
Additionally, the request for Guru Rinpoche to "please bless us, please come here and give us your blessing" points up the relationship between the qualities that Padmasambhava embodies and how we have to want to generate and develop those qualities in ourselves. Enlightenment is always within us, always present, how can we see it?
We "already have Buddha nature; how come we [are] not all a buddha?" Rinpoche pointed out it’s owing to our own delusions that we’ve had since birth (and before); however, "Delusion is a temporary obscuration." That said, in practicing the prayer, we "must truly ask from the bottom of our heart" to receive these blessings and thereby, accomplish realization.
Guru Rinpoche is the emanation of all buddhas; past, present, and future. This brings us to the mantra: "Guru pema siddhi hung."
"Guru" is the sanskrit term for teacher that is translated into Tibetan as lama (bla-ma). The life-essence of all buddhas’ wisdom is "bla" and the unobstructed compassion for all sentient beings is "ma". Keeping this in mind adds weight (another meaning of "bla"). The mantra sums up and acts a practice unto itself as follows (here we revert to transliterating Sanskrit as opposed to trying to capture the Tibetan pronunciation in some transliteration):
Vajra: the dharmakaya
Guru: the sambhogakaya
Padma: the nirmanakaya
This concludes the "outer level" explanation. Next up is the "inner" explanation. If the outer is a general overview and carries with it the most basic dimension of the words and images, then the inner aspect is more "operational", more about the why of the practice of the prayer and what it does.
The answers begin here. "Prayer means making connections."
Rinpoche pointed out three different ways in which there are connections.
- That the essence/nature of sentient beings’ and the Buddha’s are "the same, exactly the same."
- Sentient beings’ confusion and suffering and Buddha’s compassion: Buddha’s compassion knows him to hold all sentient beings’ suffering; his compassion doesn’t knows him to release sentient beings from his compassion.
- Buddha’s wisdom and compassion has "total penetration to beings; all-pervasive wisdom and compassion - no separate mind." As Lama Tharchin said, "There’s not my mind, not your mind; there’s only Mind."
Guru Rinpoche’s aspiration is to calm sentient beings’ "wild emotion". This is where the prayer is a vajrayana practice; for Vajrayana is the path of Transformation. In the Vajrayana, poison is turned into medicine; the essence of afflictive emotions is wisdom.
Lama Tharchin drew some differences in methods from the other "vehicles" or "yanas" of Buddhism. In the so-called Hinayana (too often this is used as a pejorative for Theravada; I’m hoping that Rinpoche didn’t intend it thus and that in this instance, what was intended was simply a more limited-in-scope/aspiration approach to dharma), the basic practice is Rejection, pushing away the five poisons. "Train from the outside."
In the more general forms of Mahayana, the basis is in Purification. Body and speech are servants to mind and training is "from the inside, training the mind; more and more compassion."
Returning to transformation, Rinpoche likened our adventitious emotional content to fuel for generating our innate wisdom.
"How much you have firewood, that much hotter you have fire. How strong your afflictive emotions, that’s how strong your wisdom."
Lama also pointed out a key difference between Shakyamuni Buddha and Guru Rinpoche, one that I think characterizes Gautama’s place in later Buddhism; Shakyamuni had a prophecy. "I am causal; my emanation in the future (Guru Rinpoche) will be the result. His kindness is more precise than all other buddhas."
"Guru Rinpoche’s compassion/wisdom is like a hook; our faith is like a ring. These two gotta hook up!"
"Practice from the heart; not so much intellectualizing. When you think of Guru Rinpoche, there’s not really a choice except to have faith. The reception of siddhis is dependent on faith."
This ties up the inner meaning. For the secret meaning, and I stress that in this no "secret" is being given away; as it’s been explained to me, the only "secret" is what is within you, your experience and what your lama or guide or teacher shares with you. We receive teachings from all of existence and one could argue that what ripens in us is "secret." But in this context, I think it’s fair to say that we can say that we’re looking at what is implicit in the outer and inner meanings of this (or any) teaching or text.
Lama Tharchin pretty much followed Ju Mipham’s commentary on the Seven Line Prayer for this part and yet, made it very much his own. Lama went line by line and in some instances word by word through the prayer. I’m going to drop quotation marks to make this easier on the eyes. This is a great schematization of the Seven Line Prayer (and Mipham’s commentary!) that I think is extremely helpful.
ཧཱུྃ༔ Hung signifies the hidden inner meaning and more (Rinpoche had more to say about hung later in the teaching). It serves as a container for everything discussed previously and sets the sense for what is to follow.
ཨོ་རྒྱན་ = dharmakaya (hidden meaning); source of all phenomena, all Buddha’s way of abiding is dharmakaya and Buddha’s conclusions.
ནུབ་(sinking/samsara)བྱང་ (pacifying/enlightenment) མཚམས༔(inseparable); thus, ནུབ་བྱང་ is samsara - enlightenment and མཚམས is a border but not as a separator, mtshams/མཚམས indicates the inseparability of samsara and enlightenment.
པདྨ་གེ་སར་stainless; free from dualism; སྡོང་པོ་ལ༔i.e., stainless wisdom
Also, གེ་སར་ represents the immeasurable Buddha qualities, སྡོང་པོ་ལ༔ inseparable and marvelous; perfect; ever-excellent
མཆོག་གི་དངོས་གྲུབ་བརྙེས༔ those who have received the siddhis, buddhas
པདྨ་འབྱུང་གནས་ཞེས་སུ་གྲགས༔ have no cause of emotions (emotional attachment)
འཁོར་དུ་མཁའ་འགྲོ་མང་པོས་བསྐོར༔ and the retinue, expression of the dharmakaya; all manifestations are expressions of the dharmakaya.
"Emptiness is not ultimate; phenomena not relative. The dharmakaya is clueless about relativism; not accepting, not rejecting."
ཁྱེད་ཀྱི་རྗེས་སུ་བདག་བསྒྲུབ་ཀྱི༔ Shows Guru Rinpoche’s wisdom-nature of mind.
བྱིན་གྱི་རློབས་ཕྱིར་གཤེགས་སུ་གསོལ༔ "Guru Rinpoche is our origin. We are never separate; even one second! Inseparable! Guru Rinpoche is me; I am Guru Rinpoche."
གུ་རུ་པདྨ་the three kayas are inseparable; སིདྡྷི་ཧཱུྃ༔ represents the whole mind.
"Your mind is never too small, holding the whole sky. With structuring, we put Mind in a box(4). The three kayas are totally perfected within our Mind."
"Enlightenment never got locked up!" Rinpoche’s punchline to to westerner who called on a yogi and said "All I want is the key to enlightenment."
ཧཱུྃ༔ "Original Buddha is always present. We took a long nap in samsara!"
"Name, words, letters all make a description; belong to subject or object phenomena. Wisdom word is in expressible.
ཧཱུྃ༔ "Not a subjective phenomenon; not an objective phenomenon. The Seven Line Prayer is truly liberation through hearing."
"Totally engaged in Guru Rinpoche’s wisdom body, speech, and mind - how much time you spend with Guru Rinpoche, you get a vacation from samsara. Benefit comes right at the moment, not in the future!"
Lama Tharchin’s last comments summed up the value of the public talk. "Public talk is practice to inspire people to practice. Then get a wisdom teacher. Real wisdom teachers are hard to find. You know why? Not many exist!"
"Sometimes talking isn’t helpful. Need explanation. The teacher must have experience."
- Nalanda was founded sometime in the sixth century and produced a number of renowned teachers. The ruins give an idea of how vast the campus was. As Buddhism’s fortune changed, so too did Nalanda’s. My visit is documented here.
- gterma, གཏེར་མ་ (Tibetan); pronounced ter-ma; literally, cache, or hidden treasure. More specifically and technically, gterma are teachings that have been hidden by preceptors in various places including the earth, water, and air. The most esoteric are "mind gterma" that indicate specific revelations of doctrine or realization that are spontaneously realized in the mind of a disciple in a lineage. These treasures are hidden because the time for their revelation wasn’t yet ripe. Thus, gterma of Padmasambhava might only be revealed after centuries. The gterma tradition has its origin in the Nyingma school of Tibetan Buddhism. Authorship in Tibetan tradition is a bit different from how it is conceived in some other cultures. That said, consider how many teachings in the Abrahamic religions have resulted from vision-as-revelation. Thus, the person to whom the treasure is revealed is not considered the author; this has led to some controversy and accusations that not all gterma are legitimate.
- These are two important collections of gterma texts.
- Rinpoche used structuring in what I took and still take to mean the compartmentalization of discursive thought and/or perhaps the quotidian reality of everyday perception. This vis a vis the true nature of Mind.
On Lama Tharchin himself:
I’d begin with the Vajrayana Foundation at www.vajrayana.org and then, hunt around the web and touch base with people who knew him. While he was a great scholar, he’s one of those teachers who taught, and acted, more than wrote.
On Padmasambhava/Guru Rinpoche, there is an embarrassment of riches, though little that is conclusively by his hand. That said, again, you can Google, of course. The following resources are good places to start:
To jump right in:
Guenther is my starting point for comprehensive textual analysis and philosophical critical assessment. Few scholars are as polymathic as he was; that said, sometimes he could be seemingly wilfully obscure, and annoyingly so in his translations; sometimes I feel like he brought out a bazooka to swat a mosquito. I don’t know that I would call any of his translations wrong; he often worked with lamas of no small order (Chogyam Trungpa Rinpoche and Tarthung Tulku come to mind), but there’s a marked idiosyncrasy that comes with his work which I think is the mark of the pioneer. Tibetology is still in its early phase; linguistically, historically, sociologically, the work of translation needs to take a lot more into consideration than simply trying to match a Tibetan word or term with another word from another language.
The Teachings of Padmasambhava: https://www.scribd.com/doc/138655809/98760962-Herbert-v-Guenther-the-Teachings-of-Padmasambhava
Less rigorous (and/or idiosyncratic than Guenther) in their scholastic approach, but certainly on point in their translations are fine translators like Eric Pema Kunsang and Ngawang Zangpo.
This is a wonderfully moving account and translation: http://www.amazon.com/The-Lotus-Born-Life-Story-Padmasambhava/dp/962734155X
And last but not least, Ngawang Zangpo’s Guru Rinpoche: His Life and Times: http://www.amazon.com/Guru-Rinpoche-Life-Times-Tsadra/dp/155939174X
For even more links to texts: http://www.rangjung.com/authors/padmasambhava-books.htm
The gterma tradition:
This is a source of consternation for some. Before dismissing it out of hand, please consider that how knowledge is handed down, made available, exists within us has been interpreted by various traditions. From Socrates to Moses to Swedenborg to Jigme Lingpa, teachings come from vision, books, and revelation. That said, one of the best expositions is here: Gyatso, Janet (1986). `Signs, memory and history: a Tantric Buddhist theory of scriptural transmission.' JIABS 9,2: 7-35.
This is included in the references section of https://en.wikipedia.org/wiki/Terma_(religion)#References, which is a good place to start. Also, Janet Gyatso’s biography of Jigme Lingpa is well worth the read: http://www.amazon.com/dp/0691009481/.
If you want to jump in and explore, you could start here: https://en.wikipedia.org/wiki/Terma_(religion)