Longchen Nyingthig (Tibetan: ཀློང་ཆེན་སྙིང་ཐིག་, Wylie: klong chen snying thig) is a terma, revealed scripture, of the Nyingma school of Tibetan Buddhism, which gives a systematic explanation of Dzogchen. It was revealed by Jigme Lingpa (1730-1798).
The Longchen Nyingtig may be translated as 'seminal heart of Longchenpa', a reference to the central figure of Jigme Lingpa's 'pure visions' (Wylie: dag-snang) in which the texts were revealed. 'Nyingthig' (which connotes 'seminal essence' or 'heart focus'). It is worthy of note that 'thig' is an etymon of 'thig-le' which is the Tibetan translation of the Sanskrit 'bindu' the central point of the 'mandala' (Tibetan: Khor lo).
Alternate orthographies: Longchen Nyingtik.
Dzogchen teachings have been classified in three sections namely: Semde (mind class/cycle); Longde (space class/cycle); and Mengagde (direct/oral instruction class/cycle).
Shri Singha divided the Mengagde into a further four cycles: the outer, inner, esoteric, and innermost esoteric cycle. They are teachings on the "primordially pure nature" (or Kadag; Wylie: Ka Dag). The recognition of this "primordially pure nature" is called trekchö, "cutting through" all the grasping, clinging and apprehending which obscures the "primordially pure pure nature."