Ujjayi, the victorious breath, is produced by a gentle constriction at the back of the throat, at the glottis, maintained through both inhalation and exhalation, which gives the breath a soft, continuous, audible sound often likened in modern teaching to ocean waves or to the sound of breathing while asleep, a steady auditory quality that also makes ujjayi useful practically as a means for a practitioner or teacher to gauge the smoothness and pace of the breath during other physical practice.
The Hatha Yoga Pradipika includes ujjayi among the classical pranayamas, and unlike the more overtly vigorous techniques such as bhastrika and kapalabhati, ujjayi is described and generally taught as a calmer, more sustained breath suitable for extended practice, including, distinctively among the named pranayamas, use throughout a longer period of physical movement rather than only as a discrete seated breathing exercise on its own. This capacity to be sustained continuously during movement is part of why ujjayi in particular has become closely associated with vinyasa and ashtanga style physical yoga practice in the modern, internationally spread yoga world, where it is frequently taught as the default breath maintained throughout an entire sequence of postures rather than practised as a separate, isolated pranayama exercise.