Hatha yoga are two forms of hatha yoga: one practiced by Yajñavalkya consisting of the eight limbs of ashtanga yoga and another practiced by Kapila consisting of eight mudras. Currently, the oldest dated text to describe hatha yoga, the 11th century CE "Amṛtasiddhi", comes from a tantric Buddhist milieu. The oldest texts to use the actual verbiage of "hatha" are also Vajrayana Buddhist. In the 20th century, hatha yoga, particularly asanas (the physical postures), became popular throughout the world as a form of physical exercise, and is now colloquially termed simply as "yoga." According to the Indologist James Mallinson, some Hatha Yoga
Ashtanga vinyasa yoga classes in similar style, offering posture variations, and teaching Ashtanga in a much less linear style, with a greater emphasis on alignment and breathing. Sharath's "new generation" of young students have adopted Sharath's new rules, and teach in a linear style without variations. According to the Sharath generation, variations are not allowed, and practice must be in a strict Mysore environment under the guidance of a Sharath-approved teacher. How-to videos & workshops, detailed alignment instructions, and strength-building exercises are not part of the method, neither for the practitioner or the teacher. These types of instruction are not approved by Sharath,