Heart Sutra ［般若心経］ ( Prajnāpāramitā-hridaya-sūtra; Chin Pan-jo-hsin-ching;  Hannya-shingyō): Also known as the Heart of Wisdom Sutra. A short sutra containing the essence of the Wisdom sutras and briefly describing the non-substantiality or emptiness of all phenomena. Translated into Chinese by Hsüan-tsang in 649, its full title is the Heart of the Perfection of Wisdom Sutra. The original Sanskrit text and its Tibetan translation are extant, and there are several other Chinese translations, including that of Kumārajīva. Many commentaries on the Heart Sutra were produced in China and Japan, and in Japan it is one of the most popular sutras, revered particularly by the Zen and True Word (Shingon) schools.