Mastery over the Kurma Nadi
Theoretically, there is a much greater possibility of opening sushumna while sitting in either padmasana (lotus posture) or siddhasana (accomplished pose), because the whole body is centered in these poses. In siddhasana, one heel is on your perineum area. In padmasana, the body is perfectly centered; the nadis of both sides of the body are fully balanced. If you have a good padmasana, then the body is even better centered than in siddhasana. However, these two poses are very often done incorrectly. You can injure your knee or create hemorrhoids if you do siddhasana incorrectly; similarly, if you are too forceful in your padmasana and artificially impose a lock in this pose, you can create hemorrhoids. Swamiji used to discourage the use of padmasana as a meditative posture because the area of the kurma nadi tends to be too open and not under your control in that posture. So these practices are to be done mindfully and in moderation. If you can sit in these positions correctly, they can be beneficial. If not, they can cause more harm than good.
Control over the kurma nadi is more important than anything else in the practice of pranayama or meditation. To gain conscious control over both the kurma nadi and the kurma vayu (one of the subcategories of prana, which refers to stability in the body as well as the mind), it is important to practice ashvini mudra. Anatomically and physiologically, the area of the ashvini mudra is close to the colon, ovaries, uterus, and bladder. So each time you do ashvini mudra, pulling up and releasing, you are attaining conscious control over all these organs. This also speeds up the process of blood circulation throughout your system. In the process, you are also letting your kurma vayu move, creating heat. That heat is dispersed throughout your body from the kurma nadi, or kurma vayu, through ida, pingala, and sushumna to all the nadis. Although ashvini mudra doesn’t give stability of mind and body on its own, it does increase the proper circulation of energy throughout our system, so wherever there is a little bit of blockage, wherever there is a little bit of impurity here or there, that energy will touch it and the process of purification will begin.
In meditation, however, ashvini mudra is not used; mula bandha, the root lock, is pulled up and held. This creates stability in our physical body as well as energetically—the realm of kurma vayu. Kurma vayu holds all the other vayus; it is the “secretary of the interior.” Before you undertake any task or project, your internal situation has to be stable; otherwise, if you are disturbed, it will be necessary to deal with that situation, and all other projects will either go very slowly or have to be stopped.
Control over the kurma nadi is more important than anything in the practice of pranayama or meditation.
That is what holding mula bandha, the root lock, does. It should become so effortless that it is held by itself, leaving the mind entirely free, so that all of the mental energy can be fully directed toward the object of meditation. In mula bandha, heat is generated in a static way, and if the mind is concentrated and sushumna is open, the energy will only move upward. In that state, the heat—the fire, pranic force, or kundalini force—that wakes up from the kurma nadi moves along sushumna, becoming meditative energy and enhancing the beauty of your meditation. Ashvini mudra is for a physical benefit, whereas mula bandha is for a meditative benefit.
The people for whom Patanjali wrote the Yoga Sutra did not know anatomy, so he did not describe the kurma nadi, how it works, or why it helps anatomically. He simply suggested that one sit on a flat seat that is neither too hard nor too soft, be steady, and focus on the breath. Swamiji has introduced this very systematically: sit with the head, neck, and trunk in a straight line; draw up the root lock; be comfortable and steady. In other words, the basic practices develop control over the kurma nadi, and thus you purify yourself to prepare for the rising of kundalini.
Are you working with your kurma nadi by practicing the usual Himalayan Institute method of meditation? If so, you are already doing it, whether you know the name of kurma nadi or not. If you are cooking your food with fire, whether you call it “fire” or not doesn’t matter; you are getting the same result. So observe how you sit and the way you allow your body to be still. Remember, by practicing samyama (concentration, meditation, and samadhi) on the kurma nadi while sitting and breathing in the correct way, you will gain control over kurma vayu, allowing you to attain stability of body and mind.
Source: Dawn Magazine, 1990