Asana "Hatha Ratnavali" provides a list of 84 asanas, describing some of them. In the 20th century, Tirumalai Krishnamacharya taught a new system of asanas, incorporating systems of exercises as well as traditional hatha yoga, to influential Indian yoga teachers including Pattabhi Jois, founder of Ashtanga vinyasa yoga, and B.K.S. Iyengar, founder of Iyengar yoga. Together they described hundreds more asanas, revived the popularity of yoga, and brought it to the Western world. Many more asanas have been devised since Iyengar's 1966 "Light on Yoga" which described some 200 asanas; some 300 were created by Dharma Mittra. Asanas have been claimed
Ashtanga vinyasa yoga the practice have been made since its conception. Nancy Gilgoff, an early student, describes many differences in the way she was taught ashtanga to the way it is taught now. According to her experiences, some of the differences include: Pattabhi Jois originally left out seven postures in the standing sequence, but later assigned Utthita Hasta Padangusthasana and Ardha Baddha Padmottanasana before the Intermediate Series was given; Utkatasana, Virabhadrasana A and B, Parivritta Trikonasana, and Parivritta Parsvakonasana were not in the series at this point; and Jois did not give her vinyasa between sides of the body poses or between variations