The phrase “hatha yoga” is often mistakenly used as a catch-all for some kind of generic asana practice. “Basic Hatha” is a vague phrase for any series of asana-s, which usually changes from day to day, class to class, along with a tiny bit of pranayama and meditation thrown in. Most yoga schools in the West emphasize the physical postures called asana-s, since they are a form of exercise that has wide appeal. Teachers often say they teach hatha yoga without really knowing what it means.
In fact, hatha yoga is much, much more than basic physical postures. Hatha can be divided into two words: “ha” meaning “sun” and “tha” meaning “moon.” Just as this pair of syllables forms the single word “hatha,” the whole word itself contains in it the implication of joining the sun and moon. In the subtle body, this corresponds to balancing the solar energy channel (pingala-nadi) and lunar energy channel (ida-nadi), or the masculine and feminine energies within oneself. Hence hatha yoga is a type of tantric practice. Hatha as a word means “force” or “violence.” In this context of yoga it implies working with the body, breath and mind to kind of force purification on it. By nature the body is considered unclean since life itself is constantly changing and thus in constant need to attention to keep it clean and functioning. The “inner violence” that occurs within the body during the practice of hatha comes from the death of obstructions and birth of clarity. Hatha yoga also related to the force of will it takes to cause the potential energy that rests at the root cakra to ascend through the central energy channel (sushumna-nadi) eventually connecting to the crown cakra to experience the divine inner light of awareness in ourself.
In the most common text on hatha yoga, called the Hatha Yoga Pradipika, one progresses through several stages of practice, including: asana, yama-s (10 social ethics), niyama (10 personal practices), shat-karma (six ways of cleansing the body), pranayama, mudra, bandha, nada (inner sound current) and samadhi. Many asana-s are mentioned, with the 4 primary sitting postures given the most importance, since the real goal is to balance the solar and lunar energy in the body and ultimately connect with one’s divine inner light of awareness.