pages 114–122 The Gita consists of 18 chapters and 700 shlokas (verses); each chapter is named for a different form of yoga. Some scholars divide the Gita into three sections; the first six chapters (280 shlokas) deal with karma yoga, the middle six (209 shlokas) with bhakti yoga, and the last six (211 shlokas with jnana yoga. However, elements of all three are found throughout the work. Philosophical sutras Yoga is discussed in the foundational sutras of Hindu philosophy. The Vaiśeṣika Sūtra of the Vaisheshika school of Hinduism, composed between the sixth and second centuries BCE, discusses yoga. According to Johannes Bronkhorst, the Vaiśeṣika Sūtra describes yoga as "a state where the mind resides only in the Self and therefore not in the senses". This is equivalent to pratyahara (withdrawal of the senses). The sutra asserts that yoga leads to an absence of sukha (happiness) and dukkha (suffering), describing meditative steps in the journey towards spiritual liberation. The Brahma Sutras, the foundation text of the Vedanta school of Hinduism, also discusses yoga. Estimated as completed in its surviving form between 450 BCE and 200 CE,NV Isaeva (1992), Shankara and Indian Philosophy, State University of New York Press, , page 36, ""on the whole, scholars are rather unanimous, considering the most probable date for Brahmasutra sometime between the 2nd-century BCE and the 2nd-century CE" its sutras assert that yoga is a means to attain "subtlety of body". The Nyaya Sutras—the foundation text of the Nyaya school, estimated as composed between the sixth century BCE and the secondcentury CEB. K. Matilal (1986), "Perception. An Essay on Classical Indian Theories of Knowledge", Oxford University Press, p. xiv.—discusses yoga in sutras 4.2.38–50. It includes a discussion of yogic ethics, dhyana (meditation) and samadhi, noting that debate and philosophy are also forms of yoga.SC Vidyabhushana (1913, Translator), The Nyâya Sutras, The Sacred Book of the Hindus, Volume VIII, Bhuvaneshvar Asrama Press, pages 137–139 Classical era (200 BCE – 500 CE) The Indic traditions of Hinduism, Buddhism and Jainism were taking shape during the period between the Mauryan and the Gupta eras (c. 200 BCE – 500 CE), and systems of yoga began to emerge; a number of texts from these traditions discussed and compiled yoga methods and practices. Key works of the era include the Yoga Sūtras of Patañjali, the Yoga-Yājñavalkya, the Yogācārabhūmi-Śāstra, and the Visuddhimagga. Yoga Sutras of Patanjali One of the best-known early