Atiyoga, the Original Technology
The technology of early Atiyoga became blurred or even lost in later Dzogchen which brought it back into a gradual scheme based on “cause and effect” modalities of view and practice.
The single goal of the early Ati was to immediately activate the full self-knowing capacity of the Wisdom Eye. It’s methodology did not rely on mind, concepts, energy transformation or purification.
It is told that thogal used to be taught first before trekchod, before Longchenpa. That would be part of the true Atiyoga tradition. Thogal practice by-passes all the gradualist notions concerning energy transformation, purification, and gradualist sadhanas and practices.
Thogal and Yangti stimulate and activate the Wisdom Eye directly. One experiences the wisdoms of “Clear Light” that are the intrinsic luminosity of the Wisdom Eye. The kati and other “Clear Light channels” are all aspects and extensions of the Wisdom Eye.
The teachings of Dzogchen Yangti, of Dung T’so Repa, are also associated with activating the Wisdom Eye.
The initial “pointing out instruction” is aimed at doing the same through a verbal or symbolic transmission.
Ordinary meditation practices may never actually succeed in fully activating the Wisdom Eye. A Buddha Mind or Mind of Clear Light, is a fully activated Wisdom Eye.
Here is a post of mine that contains much of the technology from early Atiyoga, the Way of Light:
The Mirror and Yangti
The interior of the "thigle tongpa dronma" or "the lamp of the empty thigle" is what's known as the "space chakra" in Dzogchen. It's directly behind the forehead. It's called a "lamp" because it is illuminating Emptiness/Awareness itself.
In Yangti dark retreat we focus on this thigle by having the third eye look back at it while we are viewing the third eye staring at us while we are located in the center of the skull. As a result the totally dark room will suddenly become illuminated as the thigle tongpa dronma becomes activated. (This was experienced here as Namkhai Norbu supervised my dark retreat).
The illumination of the outer room is the light's outward radiation while at the same time it's inward illumination is the clear light of Rigpa.
Here are the main points of the first level Yangti dark retreat instructions:
“The Single, Stainless Eye of Wisdom”
1. Skull is like an inverted crystal bowl, (hollow crystal skull) very clear. If you look at the conch palace of the brain from outside, it is luminous inside, If you look outward from inside, it is luminous outside. It is apparent, but without any truly existing nature.
2. At the urna hair in the forehead, above and between the eyebrows, visualize a (vertical) bindu-like eye, like a wrathful wisdom eye, the size of a pea or the end of the little finger. It is made up of five colors: center is blue, then white, yellow, red, green. It stares intensely into the conch palace (inner skull) at the clear/white thigle tongpa dronma floating in the center of the skull.
3. Directly in line with the eye, in the direction of just above the protruding bone at the back of the skull, is a white thigle (size of a golf ball) surrounded by five-colored lights.
Focus on the white/clear ball being stared at by the inward facing third eye. Your consciousness/awareness is the thigle tongpa dronma.
This process is described typically in the Dzogchen pointing out instructions and Nyingthig Thig teachings:
There is an oral instruction about the way to look. It is said,
“It is as though your eyes were looking through the back of your head instead of looking forwards.” Mingyur Rinpoche
"It is as though your eyes are looking backwards instead of forwards as they usually do. You are looking out with your eyes but are looking back at the same time. Do not try too hard with this though, otherwise you will really make a big mistake. You just sort of look back ..." Mingyur Rinpoche
Notice the empty nature of your own awareness that is observing. There is an empty space of awareness (thigle tongpa dronma) that knows itself, but not as a thing with shape, form or substance.
"The way to do this is just to turn your attention slightly inward, not to look deeply inside, just to turn your focus from outward to inward in a very light way. The moment of recognizing this state is the blessings of the lineage." Tsoknyi Rinpoche
"The reason for this is that the ushnisha (upper crown chakra) has no size, but pervades the ultimate expanse. When the karmic-mind (sem) dissolves into the chakra of the ushnisha (upper crown chakra), buddhahood is attained."
"In the teachings of the Great Perfection, the essence-drops are described as rising up, being piled vertically above the head (third vision). And when the karmic-mind (sem) dissolves into the chakra of the ushnisha (upper crown chakra) the “exhaustion” of phenomena in suchness (chos nyid zad sa, fourth thogal vision), buddhahood, is achieved."
From end notes of "The Treasury of Precious Qualities" by Jigme Lingpa
"Buddha’s ushnisha, the protuberance on the top of his head, is not made of flesh and blood, but represents the opening of the space chakra. It is also known as the “crown chakra of great bliss.” Khenchen Palden Sherab Rinpoche
From Dilgo Khyentse's The Heart of Compassion: Thirty Seven Verses on the Practice of a Boddhisattva (translated by the Padmakara Translation Group)
"The ushnisha (gtsug tor), or crown prominence, one of the major marks of a fully enlightened Buddha, is usually represented in paintings and statues as a protuberance resembling a topknot in size, but is said to rise up from the top of a buddha's head to the infinity of space........... In the thogal practice of the Great Perfection, the ushnisha corresponds to the five-colored lights and buddhafields that manifest above one's head as the infinite display of sambhogakaya realization" (footnote 89, p. 248 Heart)."
This single post above is the most essential and secret teaching in Dzogchen. It's the key to understanding everything. Decipher it and ask questions as needed. This "space chakra" (thigle tongpa dronma) is our Mind of Clear Light. This is how to dissolve karmic mind into Dharmakaya (the "space chakra").
The karmic mind is itself an energetic formation of rigpa. This is like a sphere of water appearing as a ball of ice. When the sphere of ice looks into its own center, it discovers itself to have always been water and it's ice-like energetic formation instantly dissolves revealing itself to be water (rigpa).