It so happened in India, that spiritual practices are most often performed facing east. Accordingly, the west (conditionally) is our back, the south is the right and hot side and the north is left and cold. The Sun is associated with vital power, it rises in the east and sets (i.e. disappears) in the west. We fall asleep at sunset and our senses become silent, and they turn on at sunrise. We can see basically everything that is in front of us, on the sides, below and even sometimes from above, but we cannot see our back. We can only feel it, while there should be an inversion element, i.e. direction inward, listening to our sensations inside. The west is a symbol of the extinction of activities, the completeness of them, so it is suṣumṇā. It is also no coincidence that one of the well-known traditions, where kuṇḍalinī is worshiped in the form of the Goddess Kubjikā, is called paśchimāmnayā – the Western Doctrine. Paśchima – from paścāt (behind, the last, completed, western), therefore it is a symbol of suṣumṇā, self-absorption. Thus, paścimottānāsana is focused specifically on the direction of attention and the prāṇa in suṣumṇā along with it. This āsana is also focused on the conscious activation of suṣumṇā with pratyāhāra and the awakening of the kuṇḍalinī power.
What is अङ्ग / aṅga in yoga, is it a step or a section? On the one hand, we find following interpretations in the Viveka Mārtaṇḍa:
117. Thanks to the twelve prāṇāyāmas – pratyāhāra is achieved. Thanks to the twelve pratyāhāras – good dhāraṇā is attained.
118. Thanks to the twelve dhāraṇās – dhyāna is known, and due to the twelve dhyānas, samādhi is achieved.
On the other hand, we find quite a few texts where aṅgas often go in a sequence that is not popular for most.
Basically, the free order of aṅgas is found either in tantras or in texts that have been influenced by tantra. These are partly Purāṇas, as well as Nātha texts. If we look at the meaning of the term ‘aṅga’ in different dictionaries, it means: ‘a part’, ‘a division’, ‘relating to the base’, ‘anything inferior or secondary’, ‘supplement’, ‘contiguous’. In tantric texts, methods are sometimes named as ‘upāya’, which also means ‘a trick’, ‘a ruse’. This allows us to understand that it is impossible, in practice, to put a technique higher than its main goals, which often causes the “modern yoga“. The “parts” can be compared with the organs of the body; we cannot say that we need a heart, but we do not need a brain or liver. We need an organism in which absolutely everything works simultaneously and harmoniously. In this regard, āsanas cannot exist separately from pratyāhāra, prāṇāyāma, dhyāna or samādhi (even if it is fragmentary). The yoga state and the yoga path are primary, while aṅgas are secondary, but they all work on the main tasks.
Pratyāhāra literally translates as “taking back”, i.e. own perception from the outside inward (in oneself, or ātman). It can be said in another way: the return of consciousness and prāṇa to the source of their origin, which terminates the process of losing energy to something that is of secondary importance to you personally or has virtually no effect. Pratyāhāra returns the practitioner to his normal state, where is much energy. And this energy can then be more effectively used in the practice of dhāraṇā. If there is not enough energy, then sometimes the dhāraṇā practice can lead to fatigue and instead of increasing energy lead to an even greater loss. I will give a description of the five methods of pratyāhāra practice, which are set forth in Śāṇḍilya Upaniṣad. Also a similar description is found in Yogayājñavalkya (Ch. 7) and Vasiṣṭha Saṃhitā. Śāṇḍilya gives the following description of pratyāhāra:
अथ प्रत्याहारः। स पञ्चविधः विषयेषु विचरतामिन्द्रियाणां
बलादाहरणं प्रत्याहरः। यद्यत्पश्यति तत्सर्वमामेति प्रत्याहारः।
अष्टादशसु मर्मस्थानेषु क्रमाद्धारणं प्रत्याहारः।
तेषु क्रमादारोहावरोहक्रमेण प्रत्याहरेत्॥ ८॥
atha pratyāhāraḥ | sa pañcavidhaḥ viṣayeṣu vicaratāmindriyāṇāṁ
balādāharaṇaṁ pratyāharaḥ | yadyatpaśyati tatsarvamāmeti pratyāhāraḥ |
nityavihitakarmaphalatyāgaḥ pratyāhāraḥ |
sarvaviṣayaparāṅmukhatvaṁ pratyāhāraḥ |
aṣṭādaśasu marmasthāneṣu kramāddhāraṇaṁ pratyāhāraḥ |
kaṇṭhakūpatālunāsākśibhrūmadhyalalāṭamūrdhni sthānāni |
teṣu kramādārohāvarohakrameṇa pratyāharet ॥ 8॥
Thus, the overview of pratyāhāra. It (pratyāhāra) is the fifth method. Pratyāhāra is the effort to remove senses from their objects. Whatever you see (perceive), it is necessary to consider it as one with your higher Self. It is required to constantly consider your actions without being tied to the fruits, as a sacrifice – tyāga (practice of karma-yoga). You need to direct your perception in opposition to external objects (i.e., inside yourself).
Pratyāhāra (the fifth technique) consists in concentrating on eighteen vital points (marmas) in the body. It is required to focus on the toes, ankles, calves (on the legs), knees, hips, anus, genital, navel, heart, throat, palate, nose, eyes, the point between the eyebrows, on the forehead, at the top of the head, and do this by moving the perception along the body up and down (ārohāvaroha-kramena).
A more detailed description is given in Yogayājñavalkya: these points, which is called ādhāra in Siddha-siddhānta-paddhati, are located slightly different. If you compare all the sources on the basis of Yogayājñavalkya and Vasiṣṭha Saṃhitā, then marmas can be the following:
1) pādāṅguṣṭha (the big toe)
2) gulpha (ankle)
3) jaṅghā (ankle)
4) citimūla (base of the calf)
5) jānu (knee)
6) ūrumadhya (center of the thigh)
7) pāyu (anus)
8) dehamadhya (perineum)
9) meḍhra (genitals)
10) nābhi (navel)
11) hṛdaya (heart)
12) kaṇṭha (throat)
13) tālu (soft palate)
14) nāsamūla (the base of the nose)
15) cakṣu (eyes)
16) bhrūmadhya (between the eyebrows)
17) lalāṭa (forehead)
18) mūrdhni (the crown of the head)
Usually, prāṇa moves where the perception is directed, so in this practice like many others, prāṇa should be focused through the consistent concentration and shifting of attention to the indicated points. Prāṇa is usually scattered throughout the body at very different points, which are 108 in number according to some sources, or even more according to others. However, the point is that attention and energy have to go more and more from the periphery to the center. Prāṇa comes from the root “an” – the breath, so we can also talk about the use of breathing at these points. With slow inspiration we concentrate on one point, since pūraka means “filling with energy,” then during exhalation (recaka) we dissolve the sensation of this region. With a new breath we move on to the next point and etc., moving up and down.