Presently, there is a wide spread mistaken opinion that Hatha-Yoga is a system, which only includes the initial limbs of Raja-Yoga, which is also called Ashtanga-Yoga (eight-limbs Yoga) Pantanjali. Some think that it comprises the first four limbs: Yama, Niyama, Asana, and Pranayama.
Some ignore the first two branches and think that Hatha-Yoga only refers to Asana and Pranayama. And others speak of Hatha-Yoga exclusively as just the practice of Asanas.
The basis for these opinions has been the first sutra from «Hatha-Yoga-Pradipika» by Swatmarama. In this sutra he says, «I worship Shiva, who taught the science of Hatha-Yoga, which is a stage that leads to achieving the peaks of Raja-Yoga». Taking this idea further, analysts concluded that Hatha-Yoga simply meant the initial levels of Raja-Yoga.
As a matter of fact, this sutra tells of Hatha-Yoga as a dialectic method of Raja-Yoga. Dialectics in this case means understanding the truth through the unity and struggle of contradictions. In Yoga, these mutually complementary opposites are Ha and Tha qualities.
Of course, these are easily noticed at the third and fourth limbs of Ashtanga-Yoga, i. e., during the practice of Asanas and Pranayamas. Here, Ha and Tha are usually connected with the straining and relaxing of particular muscle groups and with the two phases of breath: inhalation and exhalation. But what then do the initial two limbs of Hatha-Yoga, i. e., moral and ethical principles, self-discipline and hygiene have to do with this?
It is not nesessary to think that Hatha-Yoga comprise only the first four limbs of Ashtanga-Yoga, because it also deals with the «fine» controlling structures of the human organism and to a lesser extent with the «coarse» instruments.
Pratiahara and Dharana require active control of the direction of the attention rays and energetic flows. This is Ha at the level of personal Power of Will (Spirit). Dhyana and Samadhi are passive contemplation and Tha at the level of Personal Power of Will (Spirit). But the organizing Power, although a «fine» matter, is still material. And these practices, as all matter in the Universe, are covered by the principle of dualism (Ha-Tha).
According to the «Yoga-sutras» of Patanjali, there are seven types of Samadhi. And only achieving Nirvikalpa-Samadhi is liberation, a step beyond matter and dualism, or Nirvana as it is called in Buddhist Tradition.
The first two limbs, Yama and Niyama, really become possible only after achieving Samadhi. Their being placed first in the list shows the strategic genius cource of Patanjali. He suggests «starting from the completion» and laying a foundation that facilitates fast development and evolution of your consciousness, without wasting time for delusions and making karmic mistakes.
The dialectic Ha-Tha method of Raja-Yoga is the best assistance to realizing various phenomena and processes during your course of practice at any stage of yogi development. Ultimately it allows you to balance the opposing forces and achieve Complete Satisfaction and Serene Peace in the harmony of dualism and the Unity of Universe.