Semde
Semde (Tibetan: སེམས་སྡེ, Wylie: sems sde; Sanskrit: cittavarga, "mind division", "mind class" or "mind series" is the name of one of three scriptural and lineage divisions within the Dzogchen (Great Perfection) tradition. The Nyingma school of Tibetan Buddhism traditionally classifies its Dzogchen teaching into three main divisions: Semde, Longdé (Space Series) and Menngagde (Secret Instruction Series).
Semde texts are mostly said to be translations by figures of the early transmission (7th–9th centuries) of Buddhism to Tibet like Śrī Siṅgha, Vairotsana and Vimalamitra. These texts emphasize the "awakened mind" (Tibetan: byang-chub-kyi sems, Skt. bodhicitta), which is the true nature of the mind and is essentially pure and perfect, just like Buddhahood. Semde texts critique tantric practice as being based on effort, and instead promote simple and effortless contemplation of the mind and its emptiness, luminosity, purity and inherent gnosis.