The doxography employed by the Nyingma tradition to categorize the whole of the Buddhist path is unique. Nyingmapas divide the Buddhist path into 3 sutra systems, 3 outer tantras and 3 inner tantras.
In the later schools the inner tantric teachings are known as Anuttarayoga Tantra, which corresponds to Mahayoga
in the Nyingma system, while the Mahamudra teachings of the later schools are said to lead to similar results as the Dzogchen teachings.
The main Dzogchen .