Ha = Sun, Tha = Moon
Hatha is what the Western Culture conceptualizes as Yoga or what Yogic Science is all about, which is erroneous. Hatha is that specific physical practice that people associate with hippies twisting into pretzels.
As a physical science, Hatha Yoga, deals with:
- Asanas - Postures
- Pranayama - Breath Exercises
- Bandhas - Special poses that bind Prana in the body Special techniques that stoke & bind energy in the body
- Mudras - Gestures that promote and redirect circulation of Prana in the body ("circuits" that are toggled open and close like electrical
switches,create pathways for that energy to circulate in).
This science incorporates the observer into the experiment, which western science is just now wrapping its brain around with Quantum Physics. The experiment being techniques that function to tone and shift the myriad of systems within the body, with the goal to master them, to prepare the practitioner for meditation.
All this knowledge comes from ancient Vedic scriptures. Hatha Yoga Pradipika and the Yoga Sutras of Patanjali are refferences that concentrates the many "scattered" refferences from the Vedic scriptures about Hatha Yoga into a practical, codified system.
There are many forms of physical yoga (hatha) practiced these days, due to different teachers teaching students who go on to put their own little twist on it.
List of some known ones:
Hatha yoga is just one form of many practices in the Yogic Science.