The division to which the Relaxing in the Nature of Mind belongs
Relaxing in the Nature of the Mind is included in the division of Atiyoga, the unsurpassed pith instruction of the Great Perfection.
There are three main cycles in the compositions of the All-Knowing Dharma King, Gyalwa Longchen Rabjampa: the cycle of the Cause Vehicle of Characteristics, the cycle of the Result Vehicle of Secret Mantra and the cycle of the Natural Great Perfection. This text is included within the cycle of the Natural Great Perfection.
Within the cycle of the Natural Great Perfection, there is the vast paṇḍita cycle, the Seven Treasuries, which include: Precious Treasury of Tenets, Precious Treasury of the Supreme Vehicle, Wishfulling Precious Treasury, Precious Treasury of Intimate Instructions, Precious Treasury of Words and Meanings, Precious Treasury of the Dharmadhātu and Precious Treasury of Reality. Since they correspond with and totally unravel the intention of the tantras of the vast whole reality of the Natural Great Perfection with citations, reasoning and intimate instructions, it is the vast paṇḍita cycle.
The so-called “profound kusuli cycle” is the profound Quintessence [yang tig] Trilogy: Guru Quintessence, Ḍākinī Quintessence and Profound Quintessence.
The Trilogy of Relaxation gathers all of the profound and vast stages of the path into one textual system, demonstrating the profound and vast path completely and unerringly, said to be the cycle of the gradual path of pith instructions of the Great Perfection.
In general, this is a so-called “intimate instruction” [upadeśa]. Though we do indeed say Tantra Mahāyoga, Agama Anuyoga and Upadeśa Atiyoga, in this context, “intimate instruction” [has the following meaning]: “Tantra” means the seventeen tantras of the definitive great secret. “Agama” means the texts that clearly delineate the intimate instructions that unravel the intention of the meaning of the tantras composed by Nirmanakāya Garab Dorje, Guhyapati Vajradharma, Vidyādhara Śrī Siṃha, the All-knowing Longchenpa and so on.
In terms of “Upadeśa”, there are written intimate instructions and unwritten intimate instructions. Further, so-called “intimate instructions” are the one hundred and nineteen different intimate instructions that condense the critical points found within the seventeen tantras of the definitive great secret. So-called “intimate instructions” unravel the meaning of the tantras with both the tantras and the intimate instructions. Further, intimate instructions clarify everything that is hidden, concealed, scattered, shuffled and so on within the body of a tantra. As it is said [in the Guhyagarbha Tantra]:
Take out the concealed hidden meaning
that exists in the Teacher’s mind vajra…
Here, [intimate instruction] primarily [means], as the tantra of the definitive great secret, Union of the Sun and Moon, states:
…encountered in the guru’s instructions…
The text that outlines all the uncommon intimate instructions that have been passed down in an oral lineage from the original protector Samantabhadra up to the glorious root guru, our own sublime supreme guide, the text that condenses all the stages of practice of the essentials of the path from the vehicle of gods and men (for a higher state in the world) up to the vehicle of the Natural Great Perfection, the perfect wishfulling text of the great stages of the path of the intimate instructions which show clearly how one person on one seat methodically traverses the entire path without error is the Relaxing in the Nature of the Mindof the Great Perfection.