What is quite fascinating about the way Yoga texts were written and compiled in medieval India is that they often provide systemised hierarchical methods for achieving a goal or series of goals. Not unlike the brief self improvement lists that circulate widely on social media today, such as '10 ways to authentic happiness' or '7 tips for staying young'.

The Gheraṇḍa Saṃhitā (early 18th century) is an example of such a text. It identifies seven means for achieving it's yoga, the 'Yoga of the Body' (ghaṭasthayoga). As James Mallinson states,
"...it refers to the body, or rather the person, since the techniques taught by Gheraṇḍa work on both the body and mind."
The seven practices (saptasādhana) are outlined with descriptions of both the methods and the outcome produced once mastered:
1. PURIFICATION is achieved through Ṣaṭkarma (6 types of cleansing techniques)
2. STRENGTH is achieved through Āsana (32 types of postures)
3. STEADINESS is achieved through Mudrās (25 types of seals)
4. CALMNESS is achieved through Pratyāhāra (5 types of sensory withdrawal)
5. LIGHTNESS is achieved through Prāṇāyāmas (10 types of breathing exercises)
6. REALISATION OF SELF is achieved through Dhyāna (3 types of meditation)
7. STAINLESS PERFECTION is achieved through Samādhi (6 types of absorption)
The text focuses on the physical techniques that need to be practised in order to perfect both the body and mind to achieve it's goal, Rājayoga (a synonym for samādhi). Like most other Haṭhayoga systems, the seven practices in the Gheraṇḍa Saṃhitā do not contain ethical guidelines, such as those instructed in the yamas and niyamas of the Pātañjalayogaśāstra.

Interestingly, however, the Gheraṇḍa Saṃhitā does provide a unique set of six techniques for attaining particular types of samādhi, the state of meditative absorption that is liberation.

In most Haṭha and Rājayoga traditions, meditation techniques such as Śāmbhavī and Khecarī Mudrās are prominent for achieving samādhi and these techniques feature in the Gheraṇḍa Saṃhitā.  However, the Gheraṇḍa Saṃhitā also includes Yoni Mudrā, two prāṇāyāma (breath retention) techniques and Bhakti (devotion) in its sixfold system of Rājayoga.

These six techniques are not unique in themselves, as they are found in earlier traditions, but this set of six is an unusual selection and raises many questions. For example:
The Gheraṇḍa Saṃhitā teaches ten prāṇāyāma techniques, so why does it single out Bhrāmarī and Manomūrccha for inclusion in its sixfold system of Rājayoga (samādhi)? 
If one successfully practises each technique in the sixfold system to achieve samādhi, are the other techniques in the earlier chapters (i.e., the ṣaṭkarma, āsana, etc.) made redundant? 
Why is Bhakti included as a means to achieving samādhi when it largely absent in Haṭha and Rājayoga systems before this time? 
The first four of the six techniques of Rājayoga produce specified qualities or types of samādhi, that is to say Dhyāna, Rasānanda, Layasiddhi samādhi and Nāda respectively. Why are different types of samādhi not specified for the other two techniques, Manomūrccha and Bhakti
Different types of samādhi are included within Pātañjalayogaśāstra tradition, but levels and types of samādhi are altogether absent from the Haṭha and Rājayoga traditions. Is this system the only late medieval yoga text to refer to different types of samādhi
Mallinson has published an English translation of the Gheraṇḍa Saṃhitā along with an informative introduction that provides the important context necessary for understanding some of its teachings.