(Idā Nāḍī): The “comfort energy channel.” It is the passive, feminine, yin energy channel in the subtle body. It lies to the left of sushumna nadi, and its energy is complementary to that of pingala nadi (the masculine, active, yang energy channel that is to the right of neutral sushumna). Ida nadi, also known as chandra nadi, begins at a subtle level in muladhara chakra, goes along the back on the left side of the spine, and intersects with pingala nadi in ajna chakra (the coordinator of polarity in the being).