There are five stages. You should practise each one in turn in the following order.
Stage 1: breathing awareness
Close the eyes.
Hold the back straight.
Breathe deeply in and out without retention.
One round equals exhalation and inhalation.
Do as many rounds as time permits.
Let the breath become deeper and more subtle.
Fix awareness on the rhythmical flow of breath.
Then after a number of rounds, at least 20, proceed to stage 2.
Stage 2: synchronization of breathing with Om
Continue the deep breathing.
Mentally synchronize the mantra Om with the breath.
The sound ‘O’ should arise with inhalation.
The sound ‘M-M-M-M’ should arise with exhalation.
Remember, the sound is mental.
Breathe through the nose, keeping the mouth closed.
Continue in this manner with awareness of the flow of breath and the mantra.
Stage 3: individual chakra awareness
Continue stage 2.
Simultaneously fix your attention on any one of the chakras, at the bhrumadhya (eyebrow centre) or nasikagra (nose tip).
Choose any one centre.
We recommend the eyebrow centre.
Feel that you are breathing in with the mental sound ‘O’ at that centre.
Feel that you are breathing out with the mental sound ‘M-M-M-M’ at that centre.
Continue in this manner with awareness of breath, mantra and psychic centre.
Stage 4: chakra piercing
Fix your attention at sahasrara.
With inhalation and the sound ‘O’ feel that all the chakras are being pierced in turn in the following order, starting from sahasrara: ajna, vishuddhi, anahata, manipura, swadhisthana, mooladhara.
Feel the breath and ‘O’ sound moving downwards through the spine.
Then with exhalation and the sound ‘M-M-MM’ feel the chakras being pierced in turn from the mooladhara upwards to the sahasrara: swadhisthana, manipura, anahata, vishuddhi, ajna, sahasrara.
Feel the breath and sound passing upwards in the spine.
This is the end of 1 round.
Do more rounds according to the available time.
Then proceed to the final stage.
Stage 5: subtle japa
Again choose any one chakra; the best for most people is the bhrumadhya (eyebrow centre).
Continue mental repetition of Om synchronized with the breath, but now there is no need to be aware of breathing.
Be aware only of the mantra and the psychic centre.
Feel the ‘O’ and the ‘M-M-M’ sound at the chosen centre.
Continue in this manner for as long as possible.
This will lead to deep introspection and relaxation of the mind.
This is the end of the practice.
Spend about one fifth of your practice time doing each stage. That is, if you spend twenty-five minutes for the practice then devote five minutes to each stage; if you do a one hour practice program then devote twelve minutes to each stage.
Be intensely aware of your breath, the mantra and the psychic centres.
This practice soothes away tensions in the mind and makes perception introspective, sharp and one-pointed.
It can lead to dhyana (meditation).
Chaturtha pranayama is also a very useful preparatory technique for kriya voga in that it develops sensitivity to the chakras and the spinal psychic passage.