Perfect Posture or Siddhasana

Bend the left leg and grasping the ankle, draw the left foot in against the perineum .the right leg is then bent and the foot drawn in towards the body and placed in the crevice between  the calf and the thigh of the left  leg  with the heel against  the public bone . again the vertical line . both knees are on the ground and , by resting the hands or wrists on the knees or cupping the the hands in the lap , perfect  stability and symmetry can be attained and experienced , vary the order in which you cross your legs so that sometimes the right foot is in against the perineum and sometimes the left foot.

Essentials of pranayama : 

Before commencing pranayama it required that the body should be clean and free of impurities . have a  sponge down and clear your nostrils by blowing each separately . rinse your mouth with water and rub your tongue and gums with fingers . at least two hours should have elapsed since a meal .the exercise should be performed in the open , before an open window,or at least in an airy room .wear loose fitting clothes,but do not risk catching cold. remove constricting collars and ties.

Breath control :

Breath control is at the very heart os hatha yoga practice . the air passing through the right nostril  is called the sum breath and that passing through the left nostrill is called the moon breath . hatha y oga unifies the postive and negative , male and female,sum and moon energies. the breath conterrol are as important as the postures, perhaps more important.