The shatkarmas (Sanskrit: षटकर्म ṣaṭkarma, literally six actions), also known as shatkriyas, are a set of Hatha yoga purifications of the body, to prepare for the main work of yoga towards moksha (liberation). These practices, outlined by Svatmarama in the Haṭha Yoga Pradīpikā as kriya, are Netī, Dhautī, Naulī, Basti, Kapālabhātī, and Trāṭaka.The Haṭha Ratnavali mentions two additional purifications, Cakri and Gajakarani, criticising the Hatha Yoga Pradipika for only describing the other six.
Hatha yoga (/ˈhʌtə, ˈhɑːtə/; Sanskrit हठयोग, IAST: haṭhayoga) is a branch of yoga that uses physical techniques to try to preserve and channel vital force or energy. The Sanskrit word हठ haṭha literally means "force", alluding to a system of physical techniques. Some hatha yoga style techniques can be traced back at least to the 1st-century CE, in texts such as the Hindu Sanskrit epics and Buddhism's Pali canon. The oldest dated text so far found to describe hatha yoga, the 11th-century Amṛtasiddhi, comes from a tantric Buddhist milieu. The oldest texts to use the terminology of hatha are also Vajrayana Buddhist. Hindu hatha yoga texts appear from the 11th century onward.
Some of the early hatha yoga texts (11th-13th c.) describe methods to raise and conserve bindu (vital force, that is, semen, and in women rajas – menstrual fluid). This was seen as the physical essence of life that was constantly dripping down from the head and being lost. Two early hatha yoga techniques sought to either physically reverse this process of dripping by using gravity to trap the bindhu in inverted postures like viparītakaraṇī, or force bindu upwards through the central channel by directing the breath flow into the centre channel using mudras (yogic seals, not to be confused with hand mudras, which are gestures).
Nauli is one of the kriyas or shatkarmas, preliminary purifications, used in yoga. The exercise is claimed to serve the cleaning of the abdominal region (digestive organs, small intestine) and is based on a massage of the internal belly organs by a circular movement of the abdominal muscles. It is performed standing with the feet apart and the knees bent.
The 15th century Hatha Yoga Pradipika claims that Nauli (magically) removes all diseases.