Kriyas are the yogic techniques to cleanse the internal organs. According to Hatha Yoga Pradipika , there are six cleansing techniques called Shat Kriyas. They are Kapalabhati, Trataka, Neti, Dhouti, Nauli and Vasti
Shat means "six" and kriya means "cleansing". Yogic kriya remove the waste materials of our internal organs which are not expelled normally. Therefore, the aims of Hatha Yoga and of the Shatkriyas are to cleanse the internal organs and thereby create harmony between the major pranic flows, Ida and pingala, and attaining physical and mental purification and balance
The shatkriyas are also used to balance the three doshas or humours in the body Kapha- the mucus, pitta- the bile and vata-the wind. According to both Ayurveda and Hatha Yoga an imbalance of the doshas will result in illness. These practices are also used before Pranayama and the other higher yoga practices in order to purify the body from toxins and to ensure safe and successful progression along the spiritual path.
These powerful techniques should never be learned from the books or taught by inexperienced people. According to the tradition only those instructed by a guru may teach others. It is essential to be personally instructed as to how and when to perform them according to individual needs.
Kapala in Sanskrit means skull; and "Bhati" means shine. So the term "kapalabhati" means an exercise that makes the skull shine. This kriya cleanse the skull. Kapalabhati is a breathing technique for purifying the frontal region of the brain. Kapalabhati cleanses the respiratory system and the nasal passage and removes the spasm in bronchial tubes. Carbon dioxide is eliminated on a large scale and impurities of the blood are thrown out. The tissues and the cells absorb a large quantity of oxygen. The practitioner keeps up good health. The heart functions properly and the circulatory and respiratory systems toned to a considerable degree
Trataka is fixing the mind by gazing steadily to an object without winking. Trataka are in two types namely, Jatra Trataka and Jyoti Trataka. While doing the practice relaxation of the eyes is important. This practice activates the tear glands and there by purifies the visual system. It improves the eyesight, promotes good concentration and will power.
Neti is intended for the purification of the nostrils. The nostrils must be kept clean. Unclean nostrils will lead to irregular breathing. Neti are in four types namely; Jala Neti, Sutra Neti, Dugdha Neti (milk is used) and in Ghrita Neti ghee is used instead of water. Sutra Neti is another technique of nasal cleaning. A waxed thread or a thin soft rubber catheter is using in Sutra Neti.
Neti kriya, in general purifies most structures in the head and neck. Neti kriya not only clears the nasal passage but also renders the nose resistant to many irritants like water, milk, ghee, rubber, cotton etc. So it is helpful to remove the hypersensitivity as seen in persons suffering from allergic rhinitis etc.
Dhouti Kriyas are meant for cleansing the upper intestinal tract up to the stomach. There are three types of Dhouti; jala Dhouti or vamana Dhouti, vastra Dhouti and danda Dhouti. Jala Dhouti or Vaman Dhouti [kunjal] is cleansing the stomach with water. In this kriya the lukewarm salt water will be drinking and vomiting. In Vastra Dhouti cloth will be using for cleansing the stomach. In danda Dhouti a rubber tube called "danda" will be using. In this technique these saline water will be drinking and taking out through the danda which will be pushed into the stomach. Dhouti practices are highly useful for gastric trouble, acidity etc. It is good for asthma. Dhouti kriya activate the digestive fire and helps to have good appetite
Nauli is one of the important Kriyas to purify and strengthen the vital internal organs as a whole. It is a yogic technique of massaging the whole abdomen and stomach by contracting and rolling the abdominal muscles, especially the rectus abdominis muscle. The practice of Agnisara kriya and Uddiyana bandha are the preparatory practices for doing the Nauli. Naulis are three types viz
Nauli Chalana: - When one has gained control over these types of Nauli, rolling of the recti muscles clockwise and anti-clockwise is practiced. This is called "Nauli Chalana"
Nauli will be helpful in removing the digestive ailments. It is very useful in curing constipation. It reduces the obesity in the stomach region. The function of liver, spleen and other glands are activated by nauli. It increases the appetite. The people who are having high blood pressure, active ulcers or hernia complaints should not practice nauli
The word "Vasti" is a general term pertaining to the lower abdomen, belly, pelvis and bladder. Vasti kriya is a Hatha Yoga process of yogic enema to clean the colon by sucking water through anus. The Vasti practices should be done in empty stomach in the early morning.
Vasti is practiced in different ways: