Generally, the Nyingma vajrayana transmission lineage is classified into three main groups:
(1) Kama (Italic textbk’a-ma), Oral Transmission Lineage;
(2) Terma (gter-ma,) Concealed Treasures Transmission Lineage;
(3) and Daknang, (dag-snang) Visionary Lineage.
These three are further summarized into two basic transmission lineages:
(1) The Oral Transmission Lineage – the unbroken oral lineage of the Dzogchen tantras of Mahayoga, Anuyoga, and Atiyoga and other associated texts belonging to these subjects.
(2) The Treasure Transmission Lineage – the treasures of instructional scriptures, statues, and other spiritual artifacts hidden by the Guru Padmasambhava sometime in 8-9th century that are revealed later by many great Tertöns, the Treasure Masters, through their enlightened mind and meditative visions.