Dzogchen Master Chögyal Namkhai Norbu has written an extensive commentary on the root teachings by the great translator Vairocana from the 8th century, Nyida Khajor, the Union of Sun and Moon Yantra, based on his personal training and knowledge of Yantra Yoga received from his uncle and various teachers in Tibet. Chögyal Namkhai Norbu began teaching Yantra Yoga in the beginning of the 70′s in Italy.