This is by far the largest division of the Tengyur, containing no less than 2,626 works.
Traditionally it is presented as one undivided collection. Here, however, it has been subdivided—not only for easy reference, but also for technical reasons, to enable slower computer systems to load the extensive title data rapidly and without timing out.
The subdivisions follow the structure set out by Zhuchen Tsültrim Rinchen, the 18th century editor of the Degé Tengyur, in his catalogue to the collection (Toh 4569). He classifies the divisions and their works from “higher” to “lower.” The initial division is into the four principal classes of tantra, together with a fifth section for works he classifies as common to all four, or with no definite affinity to a single class. The first (and very large) Unexcelled Yoga tantra class is further subdivided into four main groups, with further subdivision in some of them, and the fifth section is subdivided into the collections of which it is largely composed.
The Degé Tengyur's system of classifying the tantras is by no means the only possible one, and Tsültrim Rinchen frequently notes diverging opinions put forward by other scholars and editors. There are even differences between his classification and that of Situ Paṇchen Chökyi Jungné in the Degé Kangyur. Many of Tsültrim Rinchen’s choices were, he says, dictated by tradition and by past precedent, notably that of Butön Rinchen Drup (bu ston rin chen grub, 1290-1364), although the latter’s system is far from being fully reproduced in the Degé Tengyur.