[Amṛtanāda-Upanishad]1
The wise, having studied the Śāstras and reflected on them again and again and having come to know Brahman, should abandon them all like a firebrand. Having ascended the car of Om with Vishnu (the Higher Self) as the charioteer, one wishing to go to the seat of Brahmaloka intent on the worship of Rudra, should go in the chariot so long as he can go. Then abandoning the car, he reaches the place of the Lord of the car. Having given up mātrā, liṅga,2 and pada,3 he attains the subtle pada (seat or word) without vowels or consonants by means of the letter M without the svara (accent). That is called pratyāhāra when one merely thinks of the five objects of sense, such as sound, etc., as also the very unsteady mind as the reins of Ātmā. Pratyāhāra (subjugation of the senses), dhyāna (contemplation), prānāyāma (control of breath), dhāranā (concentration), tārka4 and samādhi are said to be the six parts of yoga. Just as the impurities of mountain-minerals are burnt by the blower, so the stains committed by the organs are burned by checking prāna. Through prānāyāmas should be burnt the stains; through dhāranā, the sins; through pratyāhāra, the (bad) associations; and through dhyāna, the godless qualities. Having destroyed the sins, one should think of Ruchira (the shining). Ruchira (cessation), expiration and inspiration—these three are prānāyāma of (rechaka, pūraka and kumbhaka) expiration, inspiration and cessation of breath. That is called (one) prānāyāma when one repeats with a prolonged (or elongated) breath three times the Gāyatrī with its vyāhṛtis and Pranava (before it) along with the śiras5 (the head) joining after it. Raising up the vāyu from the ākāś (region, viz., the heart) and making the body void (of vāyu) and empty and uniting (the soul) to the state of void, is called rechaka (expiration). That is called pūraka (inspiration) when one takes in vāyu, as a man would take water into his mouth through the lotus-stalk. That is called kumbhaka (cessation of breath) when there is no expiration or inspiration and the body is motionless, remaining still in one state. Then he sees forms like the blind, hears sounds like the deaf and sees the body like wood. This is the characteristic of one that has attained much quiescence. That is called dhāranā when the wise man regards the mind as saṅkalpa and merging saṅkalpa into Ātmā, contemplates upon his Ātmā (alone). That is called tārka when one makes inference which does not conflict with the Vedas. That is called samādhi in which one, on attaining it, thinks (all) equal.
Seating himself on the ground on a seat of kuśa grass which is pleasant and devoid of all evils, having protected himself mentally (from all evil influences), uttering ratha-mandala,6 assuming either padma, svastika, or bhadra posture or any other which can be practised easily, facing the north and closing the nostril with the thumb, one should inspire through the other nostril and retain breath inside and preserve the Agni (fire). Then he should think of the sound (Om) alone. Om, the one letter is Brahman; Om should not be breathed out. Through this divine mantra (Om), it should be done many times to rid himself of impurity. Then as said before, the mantra-.knowing wise should regularly meditate, beginning with the navel upwards in the gross, the primary (or less) gross and subtle (states). The greatly wise should give up all (sight) seeing across, up or down, and should practise yoga always being motionless and without tremor. The union as stated (done) by remaining without tremor in the hollow stalk (viz., Sushumnā) alone is dhāranā. The yoga with the ordained duration of twelve mātrās is called (dhāranā). That which never decays is Akshara (Om) which is without ghosha (third, fourth, and fifth letters from K), consonant, vowel, palatal, guttural, nasal, letter R and sibilants. Prāna travels through (or goes by) that path through which this Akshara (Om) goes. Therefore it should be practised daily, in order to pass along that (course). It is through the opening (or hole) of the heart, through the opening of vāyu (probably navel), through the opening of the head and through the opening of moksha. They call it bila (cave), sushira (hole), or mandala (wheel).7
(Then about the obstacles of yogi). A yogin should always avoid fear, anger, laziness, too much sleep or waking and too much food or fasting. If the above rule be well and strictly practised each day, spiritual wisdom will arise of itself in three months without doubt. In four months, he sees the devas; in five months, he knows (or becomes) Brahmanishtha; and truly in six months he attains Kaivalya at will. There is no doubt.
That which is of the earth is of five mātrās (or it takes five mātrās to pronounce Pārthiva-Pranava). That which is of water of four mātrās; of agni, three mātrās; of vāyu, two; and of ākāś, one. But he should think of that which is with no mātrās. Having united Ātmā with manas, one should contemplate upon Ātmā by means of ātmā. Prānā is thirty8 digits long. Such is the position (or range) of prānas. That is called Prāna which is the seat of the external prānas. The breaths by day and night are numbered as 1,13,180.9 (Of the prānas) the first (viz.,) Prāna is pervading the heart; Apāna, the anus; Samāna, the navel; Udāna, the throat; and Vyāna, all parts of the body. Then come the colours of the five prānas in order. Prāna is said to be of the colour of a blood-red gem (or coral); Apāna which is in the middle is of the colour of Indragopa (an insect of white or red colour); Samāna is between the colour of pure milk and crystal (or oily and shining), between both (Prāna and Apāna): Udāna is apāndara (pale white); and Vyāna resembles the colour of archis (or ray of light). That man is never reborn wherever he may die, whose breath goes out of the head after piercing through this mandala (of the pineal gland). That man is never reborn.
1. The Upanishad treating of Nāda (spiritual sound) which is Amṛta (nectar). Here Prānas are spoken of, as they produce Nāda within and without.
2. It is said to be the subtle, gross and other microcosmic bodies. It also means sign.
3. It is said to be the macrocosmic bodies of Virāt, etc. It means a word or letter.
4. In this classification, tārka is introduced newly. It means; the examination of the mind being attracted to objects and knowing that siddhis are impediments to progress.
5. The vyāhṛtis are Bhūḥ, Bhuvaḥ, etc., and the head is Om, Āpo, etc.
6. Lit., car-circle which is a mystical chakra or diagram for invoking the devatā; but some commentators make ratha mean Om: and mandala, the circle of Śiva.
7. There are four openings in the body; three from which the astral, the lower mental and the higher mental bodies escape: the last being of turya.
8. As measured by the width of the middle finger: Yājñavalkya says, Prāna is 12 digits beyond the body.
9. One commentator makes it thus: Taking 21,600 for each of the five Prānas, we get 1,08,000: for the five sub-prānas, 5 × 1036 is 5,180. Hence the total is 1,13,180. Another commentator makes it 21,600 alone.