The Tibetans did not have a formally arranged Mahayana canon and so devised their own scheme which divided texts into two broad categories:
Kangyur (Wylie: bka'-'gyur) or "Translated Words or Vacana", consists of works supposed to have been said by the Buddha himself. All texts presumably have a Sanskrit original, although in many cases the Tibetan text was translated from Chinese or other languages.
Tengyur (Wylie: bstan-'gyur) or "Translated Treatises or Shastras", is the section to which were assigned commentaries, treatises and abhidharma works (both Mahayana and non-Mahayana). The Tengyur contains 3626 texts in 224 Volumes.
^Tibetan: rgyud. The distinction between sutra and tantra is not rigid. For example, in some editions the tantra section includes the Heart Sutra (Cf. Conze, The Prajnaparamita Literature, Mouton, the Hague, 1960, page 72.) and even versions of texts in the Pāli Canon (Mahasutras, Peter Skilling, Pali Text Society, volume I, page xxiv. The abbreviation DN there is given in the author's list, page xv, as Digha Nikaya, which is part of the Pali Canon.)