Nadis and Yoga

"Nad" means movement. In the Rig Veda, it means stream. In Yoga, nadis are the channels of Kundalini energy. The Nadis thus are channels, but not only nerves (snayu). The subtle channels or Yoga Nadis are the channels of mind and the channels of chitta, the feeling self or being. The gross channels of subtle energy are visible as cords, vessels or tubes, including acupuncture meridians, nerves, muscles, arteries, veins, lymph,... When an aspirant of Kundalini Yoga starts activating the Kundalini energy through various kinds of pranayamas, the nadi system is vitalized. This is not only very good for health, it also very much promotes spiritual growth and understanding.

Ayurveda mentions 72.000 different Nadis. Tantra Yoga identifies 14 principal nadis of which the following three are the most important :

Sushumna	Passes through the spinal column, originating in the Muladhara Chakra and terminating in the Sahasrara Chakra, diving in an anterior and posterior branch before reaching the Ajna Chakra. The Sushumna generally remains dormant when the other Nadis flow strongly and is activated only when the breath comes through both nostrils simultaneously. It can also be activated through pranayama and Swar Yoga and operates automatically at dawn and dusk, calming down the system and making meditation easy.
Ida	The Ida Nadi starts and ends to the left of the Sushumna, but is also connected with the left testicle in males. It terminates in the left nostril, stimulating the right side of the brain. It is feminine in energy, carries pranic energy and is one of the most important mental nadis. As it nourishes and purifies the body and the mind, it is also called Ganga in Tantric scriptures. When Sushumna is not working, activating the Ida Nadi is the best way to facilitate meditation.
Pingala	The Pingala Nadi starts and ends to the right of Sushumna. It is the carrier of solar, male energy, adding vitality, physical strength and efficiency. It is also purifying like Ida Nadi, but cleansing like fire. It is activated by the breath in the right nostril where it stimulates the left side of the brain. Bhedana pranayama is used to activate this nadi and is recommended for physical activities, debates and, indeed, duels.

The remaining of the 14 principal nadis are Gandhari, Hastajihva, Yashasvini, Pusha, Alambusha, Kuhu, Shankini, Sarasvati, Payasvini, Varuni, Vishvodara.

The Kuhu Nadi for example causes ejaculation together with the Chitrini Nadi. The mastering of this nadi is the main objective of the Vajrauli exercise, allowing the male aspirant to raise the seminal fluid from the second chakra to the Soma Chakra within the Sahasrara Chakra, along with the vaginal fluid from his female counterpart. It is this practice which is often known as Tantric Sex, which created a lot of attraction to Tantra in the West.