(Sanskrit, literally “great seal” or "great symbol"; Tibetan Chagya Chenpo) The method of direct introduction to the nature of the consciousness (or Buddha-nature) and the practice of stabilizing the accompanying transcendental realization. This teaching originated in India and was propagated in Tibet. Teachers of this method include Maitreya, Asanga, Atisha, Nagarjuna, Marpa, Milarepa, Gampopa, and many more. While primarily related to the Kagyu school, it is also studied and practiced in the Gelug and Sakya schools. Very similar teachings are found in the Nyingma school, but are called Dzogchen, which means “Great Perfection, Great Completeness, Total Completeness, Supercompleteness..." The instructions that point to the Dzogchen state are sometimes described as a set of "inner" or "heart" (Tib. snying thig) teachings. Students of Dzogchen and Mahamudra often attend each others schools, because the two are so similar.
"The disciple must receive instructions from his own Innermost, and the duty of the Innermost is to instruct his Bodhisattva, that is to say, his Soul who is anxious for Light. The doctrine of “Shin-Sien” teaches that the human mind is like a mirror, which attracts and reflects each dust atom, and has to be dusted each day, until becoming a “Christ-mind.” Shin-Sien was the sixth patriarch of northern China, who taught the esoteric doctrine of “Bodhidharma.” In Sanskrit, the internal chamber of the heart is called “Brahma-pura” (the city of the supreme God). The disciple should become a master of Samadhi. Buddha dharma is the religion of wisdom in China. The doctrine of the heart is called the seal of the truth, or the “true seal.” - Samael Aun Weor, The Zodiacal Course