Changes

There are as many Upanishads to each Veda as there are Sakhas, branches or recensions, i.e., 21, 109, 1000 and 50 respectively to the four Vedas, the [[Rigveda|Rig-Veda]] the [[Yajurveda|Yajur Veda]], the [[Samaveda (सामवेद)|Sama Veda]] and the [[Atharvaveda|Atharva-Veda]].<ref name=":022" />

There are as many Upanishads to each Veda as there are Sakhas, branches or recensions, i.e., 21, 109, 1000 and 50 respectively to the four Vedas, the [[Rigveda|Rig-Veda]] the [[Yajurveda|Yajur Veda]], the [[Samaveda (सामवेद)|Sama Veda]] and the [[Atharvaveda|Atharva-Veda]].<ref name=":022" />

More than 200 Upanishads are known, of which the first dozen or so are the oldest and most important and are referred to as the principal or main (''[[mukhya]]'') Upanishads from the Vedantic point of view. The ''mukhya'' Upanishads are found mostly in the concluding part of the ''[[Brahmana (ब्राह्मणम्)|Brahmanas]]'' and ''[[Aranyaka (आरण्यकम्)|Aranyakas]]'' and were, for centuries, memorized by each generation and passed down verbally. Muktikopanishad and Narayanopanishad lists 108 Upanishads and of them Dasa-Upanishads are <blockquote>ईश-केन-कठ-प्रश्न-मुण्ड-माण्डूक्य-तित्तिरः । एेतरेयं च छान्दोग्यं बृहदारण्यकं तथा ॥ </blockquote><blockquote>''īśa-kēna-kaṭha-praśna-muṇḍa-māṇḍūkya-tittiraḥ । ēētarēyaṁ ca chāndōgyaṁ br̥hadāraṇyakaṁ tathā ॥''</blockquote>Isa, Kena, Katha, Prasna, Mundaka, Mandukya, Taittriya, Aitareya, Chhandogya, Brihadaranyaka are listed as Dashopanishad.  

More than 200 Upanishads are known, of which the first dozen or so are the oldest and most important and are referred to as the principal or main (''[[mukhya]]'') Upanishads from the Vedantic point of view. The ''mukhya'' Upanishads are found mostly in the concluding part of the ''[[Brahmana (ब्राह्मणम्)|Brahmanas]]'' and ''[[Aranyaka (आरण्यकम्)|Aranyakas]]'' and were, for centuries, memorized by each generation and passed down verbally. Muktikopanishad and Narayanopanishad lists 108 Upanishads and of them Dasa-Upanishads are <blockquote>ईश-केन-कठ-प्रश्न-मुण्ड-माण्डूक्य-तित्तिरः । एेतरेयं च छान्दोग्यं बृहदारण्यकं तथा ॥ </blockquote><blockquote>''īśa-kēna-kaṭha-praśna-muṇḍa-māṇḍūkya-tittiraḥ । ēētarēyaṁ ca chāndōgyaṁ br̥hadāraṇyakaṁ tathā ॥''</blockquote>Isavasyopanishad Kena, Katha, Prasna, Mundaka, Mandukya, Taittriya, Aitareya, Chhandogya, Brihadaranyaka are listed as Dashopanishad.  

Besides Shvetashvatara, Kaushitaki and Maitrayaniya Upanishads are also listed as older ones. Shri Adi Shankaracharya has given bhashyam (commentary) for these ten principal Upanishads and has mentioned about Kaushitaki and Shvetasvatara Upanishads in his writings, though he did not write the bhasyam for these two Upanishads. These 13 Upanishads are based on the ancient vedic sources and advocate the tattava of Vedanta. The many other Upanishads that are currently available have arisen based on the particular sampradayas, thus we find mainly Shaiva, Vaishnava, Yoga and Shakteya Upanishads<ref name=":42222" />.

Besides Shvetashvatara, Kaushitaki and Maitrayaniya Upanishads are also listed as older ones. Shri Adi Shankaracharya has given bhashyam (commentary) for these ten principal Upanishads and has mentioned about Kaushitaki and Shvetasvatara Upanishads in his writings, though he did not write the bhasyam for these two Upanishads. These 13 Upanishads are based on the ancient vedic sources and advocate the tattava of Vedanta. The many other Upanishads that are currently available have arisen based on the particular sampradayas, thus we find mainly Shaiva, Vaishnava, Yoga and Shakteya Upanishads<ref name=":42222" />.