Dorje Lingpa (rDo rje gling pa, 1346–1405) is one of the five kingly tertöns or treasure-discoverers (gter ston rgyal po lnga) of the Nyingma school of Tibetan Buddhism. Among his numerous termas or treasures, the lTa ba klong yangs (Vast expanse of view), a Dzogchen tantra with 53 chapters, is considered to be the essential one. In this paper, I will introduce the following findings: (1) His lTa ba klong yangs sometimes belongs to the Section of Expanse (Klong sde), at other times to the Section of Direct Instruction (Man ngag sde), and at still other times to the Great Ati (Ati chen po) . (2) The lTa ba klong yangs is greatly influenced by the sNying thig literature. (3) The lTa ba klong yangs contains many parallels, often verbatim similiarities, with the Great Tantra, the rGyud chen dri med zla shel (Unstained crystal), a Dzogchen tantra consisting of 70 chapters. (4) The latter seems to be a terma of Sherab Membar (Shes rab me ’bar), a treasure-discoverer, equally of the 14th century. In this case, the similarity of the two tantras could point towards a close relationship between these two tertöns.
