This is the method described in the Hatha Yoga Pradipika.
Take a comfortable sitting position.
Hold the spine and head erect but without tension.
Place the hands on the knees.
Close the eyes and relax the whole body.
Let the breathing become deeper.
Now start the practice of surya bheda.
Raise your right hand in front of the face in nasagra mudra.
Place the index (second) and middle (third) fingers on the forehead with the ring (fourth) finger and thumb on either side of the nose.
Close the left nostril with the ring finger.
Inhale slowly and deeply through the right nostril.
At the end of inhalation, close both nostrils with the ring finger and thumb.
Hold your breath for a comfortable length of time.
Do not strain.
Then release the pressure of the ring finger.
Breathe out slowly through the left nostril.
This is 1 round.
Do as many rounds as available time permits.
This is the method described in the Gherand Samhita.
Sit in a comfortable pose.
Make the preparations described in technique 1.
Then inhale deeply through the right nostril, trying to imagine that the breath is being drawn up from the reservoir of energy in the navel region.
You should feel the inhaled breath recharging the whole body.
Feel that the whole body is expanding.
At the end of inhalation close both nostrils.
Hold the breath and do jalandhara bandha.
After a comfortable period of retention, release lalandhara bandha and raise your head.
Release the pressure of the ring finger and breathe out through the left nostril.
One round is completed at the end of exhalation.
Do more rounds.
This is the method that we teach in the ashram.
Repeat technique 1 as far as retention of the breath.
Then do both jalandhara bandha and moola bandha.
Hold the breath while doing the two bandhas for as long as you feel comfortable.
Then release the two bandhas and raise the head.
Breathe out slowly through the right nostril (not the left as given in the previous practices).
At the end of exhalation start the second round.
Breathe in through the right nostril, hold the breath, do the bandhas; then release the bandhas and breathe out through the right nostril.
Do more rounds.
Maintain awareness of breath and the mechanics of the practice.
Duration and time of practice
Sun a bheda gives many benefits if done for a prolonged period of time.
However, it can cause more harm than good if your body-mind is not sufficiently purified.
We therefore suggest that you practise for no more than twenty minutes at one stretch.
The best time to practise is early in the morning before breakfast.
Do not practise after food because you will interfere with the natural energy flow associated with digestion.
The three variations seem to be quite different, especially the third technique. But actually they give very similar benefits. They awaken energy in the body and increase vitality; they are especially recommended for those people who are habitually lethargic. The practice should not be done, however, if the lethargy is due to illness. Surya bheda pranayama will help transform tamas (lethargy) into rajas (dynamism). This will help to make the mind more alert and perceptive, and will be a great help in meditative practice.