(Skt.). The sixth level of tantric teachings according to the Nyingma school, equivalent in some respects to the Non-dual Tantra class of the New Schools. The tantric texts that form this class are unique to the Nyingma school. The term is often used as a synonym for Dzogchen. The atiyoga class of teachings is further subdivided in the three groups: the Mind Category, the Spatial Category and the Secret Instruction Category.