Hatha Yoga (Sanskrit), also called Hatha Vidya, is a particular system of Yoga introduced by Yogi Swatmarama, a sage of 15th century India, and compiler of the Hatha Yoga Pradipika. In this treatise Swatmarama introduces Hatha Yoga as 'a stairway to the heights of Raja Yoga', hence a preparatory stage of physical purification that renders the body fit for the practice of higher meditation. The Asanas and Pranayama in Raja Yoga were what the Hindu Yogis used to physically train their body for long periods of meditation. This practice is called shatkarma. The word Hatha is a compound of the words Ha and Tha meaning sun and moon, referring to Praana and Apaana, and also to the principal nadis (energy channels) of the subtle body that must be fully operational to attain a state of dhyana or samadhi. According to the Monier Moneir-Williams Sanskrit Dictionary, the word "hatha" means forceful. It is a strong practice done for purification. In other respects Hatha yoga follows the same principles as the Raaja Yoga of Patanjali including moral restraint yama and spiritual observances niyama. Hatha Yoga is what most people in the West associate with the word "Yoga" and is practised for mental and physical health throughout the West.

Etymology

     Hatha Yoga is also known as hatha vidya or the "science of hatha" yoga. The word Hatha comes from combining the two Sanskrit terms "ha" meaning sun and "tha" meaning moon. The word "ha" refers to the solar nadi (pingala) in the subtle body and "tha" the lunar channel (ida). However, when the two components of the word are placed together, "hatha" means "forceful", implying that powerful work must be done to purify the body. Yoga means to yoke, or to join two things together, hence hatha yoga is meant to join together sun (masculine, active) energy with moon (feminine, receptive) energy, thus producing balance and greater power in an individual.

Origins

     The most comprehensive text of Hatha Yoga is the Hatha Yoga Pradipika by Yogi Swatmarama. This work is nonetheless derived from older Sanshatkarma (purification), asana (postures), pranayama (subtle energy control), chakras (centers of energy), kundalini (instinct), bandhas (muscle force), kriyas (techniques; manifestations of kundalini), shakti (sacred force), nadis (channels), and mudras (symbolic gestures) among other topics.

     Traditionally, Lord Shiva is credited with propounding Hatha Yoga. It is said that on a lonely island, assuming nobody else would hear him, he gave the knowledge of Hatha Yoga to Goddess Parvati, but a fish heard the entire discourse, remaining still throughout. Lord Shiva took mercy on the fish (Matsya) and made him a siddha, who came to be known as Matsyendranaatha. Matsyendranaatha taught Hatha Yoga to Chaurangi, a limbless man who was given hands and feet by Matsyendranaatha just by looking at him. Hatha Yoga Pradipika mentions Adinaatha, Matsyendranaatha, Gorakhanaatah and many other yogis who became famous Hatha Yogis.
     Many modern schools of Hatha Yoga derive from the school of Sri Tirumalai Krishnamacharya, who taught from 1924 until his death in 1989. Among his students prominent in popularizing Yoga in the West were Sri K. Pattabhi Jois, famous for popularizing the vigorous Ashtanga Vinyasa Yoga style, B.K.S. Iyengar who emphasizes alignment and the use of props, Indra Devi and Krishnamacharya's son T.K.V. Desikachar who developed the Viniyoga style. Desikachar founded the Krishnamacharya Yoga Mandiram in Chennai, with the aim of making available the heritage of yoga as taught by Krishnamacharya.
Another major stream of influence was Swami Sivananda of Rishikesh (1887-1963) and his many disciples, including Swami Vishnu-Devananda - founder of International Sivananda Yoga Vedanta Centres, Swami Satyananda - of the Bihar School of Yoga, and Swami Satchidananda - of Integral Yoga, among others.

Concept

     Traditional Hatha Yoga is a holistic yogic path, including moral disciplines, physical postures asanas, purification procedures shatkriyas, poses mudras, yogic breathing pranayamas and meditation. The Hatha yoga predominantly practised in the West consists of mostly asanas understood as physical exercises.
Hatha Yoga is one of the two branches of Yoga that focuses on the physical culture, the other one being Raja Yoga. Both of these are commonly referred to as Sadanga Yoga, i.e., Yoga of six parts ('sad' meaning six and 'anga' meaning limbs). The six limbs are described below in detail. Svatmarama emphasies many times in his Hathapradipika text that there is no Raja Yoga without Hatha Yoga and no Hatha Yoga without Raja Yoga. The main difference is that Raja Yoga uses asanas mainly to get the body ready for prolonged meditation, and hence focuses more on the meditative asana poses: Lotus Posture Padmasana, Accomplished Posture Siddhasana, Easy Posture Sukhasana and Pelvic Posture Vajrasana. Hatha Yoga utilizes not only meditative postures but also cultural postures. Similarly, Raja Yoga's use of Pranayama is also devoid of extensive locks Bandhas.
     Hatha represents opposing energies: hot and cold (fire and water, following similar concept as yin-yang), male and female, positive and negative. Hatha yoga attempts to balance mind and body via physical postures or "asanas", purification practices, controlled breathing, and the calming of the mind through relaxation and meditation. Asanas teach poise, balance and strength and are practised to improve the body's physical health and clear the mind in preparation for meditation in the pursuit of enlightenment. However if an individual has too much phlegm or fat then purification procedures are a necessity before undertaking pranayama.
     Ashtanga is the yoga of Patanjali, the compiler of the Yoga Sutras. It is composed of eight limbs: Yama and Niyama, which are ethical obligations; Asana; Pranayama, which is breath control; Pratyahara, which is sense withdrawal; Dharana, which is concentration; Dhyana, which is meditation; and Samadhi, which is the experience of unity with God. The eight limbs are more precisely viewed as eight levels of progress, each level providing benefits in and of itself and also laying the foundation for the higher levels. Frequently Ashtanga Yoga of Patanjali is being confused with Raja Yoga, Patanjali nowhere in his sutras uses the term Raja Yoga.
     Note: Hatha Yoga consists of six limbs focused on attaining Samadhi. In this scheme, the six limbs of Hatha Yoga are defined as Asana, Pranayama, Pratyahara, Dharana, Dhyana and Samadhi. The basic text of Hatha Yoga is Hathapradipika by Svatmarama, a grand desciple of Sahajananda (from the lineage of Sopana, the younger brother of Jnaneshwar Maharaj of Alandi near Pune). An important part of hatha practices is awakening of Kundalini. The signs of success in hatha yoga are slenderness of the body, cheerful face, hearing mystical sound, bright eyes, sense of well-being, control over the bindu, increase in gastric fire and purification of the nadis.

Yama and niyama

Yama is a "moral restraint" or rule for living virtuously. Ten yamas are codified in numerous scriptures, including the Hatha Yoga Pradipika compiled by Yogi Swatmarama, while Patanjali lists five yamas, and five niyamas (disciplines) in the Yoga Sutra.
The ten traditional yamas are:

• Ahimsa: Nonviolence. Abstinence from injury, or harm to any living creature in thought, word, or deed. This is the "main" Yama. The other nine are there in support of its accomplishment.
• Satya: Truthfulness in word and thought (in conformity with the facts).
• Asteya: No stealing, no coveting, no entering into debt.
• Brahmacharya: Divine conduct, continence, celibate when single, faithful when married.
• Kshama: Patience, releasing time, functioning in the now.
• Dhriti: Steadfastness, overcoming non-perseverance, fear, and indecision; seeing each task through to completion.
• Daya: Compassion; conquering callous, cruel and insensitive feelings toward all beings.
• Arjava: Honesty, straightforwardness, renouncing deception and wrongdoing.
• Mitahara: Moderate appetite, neither eating too much nor too little; nor consuming meat, fish, shellfish, fowl or eggs.
• Shaucha: Purity, avoidance of impurity in body, mind and speech.

     Patanjali's five yamas, or moral restraints, are ahimsa (non-injury), satya (truthfulness), asteya (non-stealing), brahmacharya (continence or chastity) and aparagriha (abstinence from avarice). He also lists five niyamas, or disciplines, which include shauca (purity), samtosha (contentment), tapas (asceticism), svadhyaya (study), and ishvara-pranidhana (devotion to the Lord).

Asanas (postures)

     Asanas are contemplative in nature and were originally intuited by yogis during meditation; the Kundalini naturally brings forth these postures or movements, called Kriyas, during deep meditation. These movements are meant to help to remove blockages (disease) in the causal, subtle, and physical bodies.
In the ancient author Patanjali's work, Asana is classified as the third rung of eight in the ladder of the practice of Raja Yoga.
     Hatha yoga in the West primarily concerns itself with asanas or postures.

Pranayama (breathing)

     The words 'Prana' (life-force) and 'Ayama' (to lengthen or regulate) make up Pranayama. Pranayama seeks to lengthen, control and regulate the breath. In one variation, the Rechak (exhaled air), Poorak (inhalation) and Kumbhak (Retention during normal inhaling and exhaling) are the three parts of the breath that are regulated. Pranayama is practised to develop mental, physical and spiritual strength. Though the beginner's Pranayama is relatively harmless, safely progressing to more advanced practices requires the guidance of a knowledgeable teacher.

Health benefits ascribed to yogasana practice

     Different asanas are recommended by practitioners to cure or prevent problems ranging from constipation to cancer. It is known to reduce stress and other mental worries.