Yoga Sūtra Chapter Two verse 50

बाह्याभ्यन्तरस्थम्भ वृत्तिः देशकालसन्ख्याभिः परिदृष्टो दीर्घसूक्ष्मः ॥५०॥

bāhya-ābhyantara-stambha-vṛttiḥ deṣa-kāla-saṃkhyābhiḥ paridṛṣṭaḥ dīrgha-sūkṣmaḥ ||50||

The external, internal and suspension fluctuations
are seen to be long and subtle
through place, time and number.

bāhya - external; being outside, situated without, outer, exterior; diverging from, conflicting with, opposed to, having nothing to do with; not belonging to the family or country, strange, foreign; excluded from caste or the community, an out-casteābhyantara - internal, being inside, interior, innerstambha - suspension; stoppage, obstruction, suppressionvṛtti - fluctuation; modification; turning; set in motion, course of action, behaviour, movement; activity, function; profession, mode of life or conduct, course of action, behaviourdeśa - place, point, region, spotkāla - time, a period of time; season, the proper time or season forsāṃkhya - enumeration; a numberparidṛṣṭa - seen to be, seen, beheld, perceived, learntdīrgha - length, long, for a long time; a long vowelsūkṣma - minute, small, fine, thin; acute, subtle, keen; an atom, intangible matter; the subtle all-pervading spirit, Supreme Soul

Commentaries and Reflections

Commentary by T Krishnamacharya:

Commentary by TKV Desikachar:

Commentary by Paul Harvey:

“Within the practice guidelines for Prāṇāyāma
Length and Subtlety are the fruits of a process,
they are not tools for use within this process.
The tools here are Deśa, Kāla and Sāṃkhya.
By these the breath becomes Dīrgha and Sūkṣma,
in other words the breath becomes Long and Subtle.”

“Some Prāṇāyāma Techniques prioritise Length.
Other Prāṇāyāma Techniques prioritise Subtlety.
While yet other Prāṇāyāma Techniques prioritise Both.”

“When working with the Breath in Āsana,
it’s perhaps less appealing initially,
but ultimately more attractive, satisfactory
and effective, to integrate a Bhāvana on
the Samāpatti of Śaithilya and Ananta,
within a developmental Prāṇāyāma Sādhana,
focused towards the Siddhi of Dīrgha or Length,
supported by its counterpoint, Sūkṣma or Subtlety.”