an internal sound) are also described in this upanishad. The practice of pranayama (focusing on the breath) is mentioned in hymn 1.5.23 of the Brihadaranyaka Upanishad, and pratyahara (withdrawal of the senses) is mentioned in hymn 8.15 of Chandogya Upanishad. The Jaiminiya Upanishad Brahmana (probably before the 6th c. BCE) teaches breath control and repetition of a mantra. The 6th-c. BCE Taittiriya Upanishad defines yoga as the mastery of body and senses. According to Flood, "[T]he actual term yoga first appears in the Katha Upanishad, dated to the fifth to first centuries BCE. Second urbanisation (500–200 BCE) Systematic yoga concepts begin to emerge in texts dating to c. 500–200 BCE, such as the early Buddhist texts, the middle Upanishads, and the Mahabharata Bhagavad Gita and Shanti Parva. Buddhism and the śramaṇa movement According to Geoffrey Samuel, the "best evidence to date" suggests that yogic practices "developed in the same ascetic circles as the early śramaṇa movements (Buddhists, Jainas and Ajivikas), probably in around the sixth and fifth centuries BCE." This occurred during India's second urbanisation period. According to Mallinson and Singleton, these traditions were the first to use mind-body techniques (known as Dhyāna and tapas) but later described as yoga, to strive for liberation from the round of rebirth. Werner writes, "The Buddha was the founder of his [Yoga] system, even though, admittedly, he made use of some of the experiences he had previously gained under various Yoga teachers of his time." He notes: Early Buddhist texts describe yogic and meditative practices, some of which the Buddha borrowed from the śramaṇa tradition.Barbara Stoler Miller, "Yoga: Discipline of Freedom: the Yoga Sutra Attributed to Patanjali; a Translation of the Text, with Commentary, Introduction, and Glossary of Keywords." University of California Press, 1996, p. 8. The Pāli Canon contains three passages in which the Buddha describes pressing the tongue against the palate to control hunger or the mind, depending on the passage. There is no mention of the tongue inserted into the nasopharynx, as in khecarī mudrā. The Buddha used a posture in which pressure is put on the perineum with the heel, similar to modern postures used to evoke Kundalini. Suttas which discuss yogic practice include the Satipatthana Sutta (the four foundations of mindfulness sutta) and the Anapanasati Sutta (the mindfulness of breathing sutta). The chronology of these yoga-related early Buddhist texts, like the ancient Hindu texts, is unclear. Early Buddhist