at a monastery in Pāṭaliputra. When Xuanzang visited Dhānyakaṭaka, he wrote that the monks of this region were Mahāsāṃghikas, and mentions the Pūrvaśailas specifically. Near Dhānyakaṭaka, he met two Mahāsāṃghika bhikṣus and studied Mahāsāṃghika abhidharma with them for several months, during which time they also studied various Mahāyāna śāstras together under Xuanzang's direction. On the basis of textual evidence as well as inscriptions at Nāgārjunakoṇḍā, Joseph Walser concludes that at least some Mahāsāṃghika sects probably had an abhidharma collection, and that it likely contained five or six books. Tattvasiddhi Śāstra The Tattvasiddhi Śāstra ("the treatise that accomplishes reality"; Chinese: 成實論, Chéngshílun), is an extant Abhidharma text which was popular in Chinese Buddhism. This Abhidharma is now contained in the Chinese Buddhist canon, in sixteen fascicles (Taishō Tripiṭaka 1646). Its authorship is attributed to Harivarman, a third-century monk from central India. This work may belong to the Mahāsāṃghika Bahuśrutīya school or to the Sautrāntika school. Paramārtha cites this Bahuśrutīya abhidharma as containing a combination of Hīnayāna and Mahāyāna doctrines, and Joseph Walser agrees that this assessment is correct. Ian Charles Harris also characterizes the text as a synthesis of Hīnayāna and Mahāyāna, and notes that its doctrines are very close to those in Mādhyamaka and Yogācāra works. The Satyasiddhi Śāstra maintained great popularity in Chinese Buddhism, and even lead to the formation of its own school of Buddhism in China, the Chéngshí school (成實宗), which was founded in 412 CE. As summarized by Nan Huai-Chin: The Chéngshí School taught a progression of twenty-seven stations for cultivating realization, based upon the teachings of this text. They took Harivarman as its founder in India, and Kumārajīva as the school's founder in China. The Chéngshí School is counted among the ten schools of Tang dynasty Buddhism. From China, the Chéngshí School was transmitted to Japan in 625 CE, where it was known as Jōjitsu-shu (成實宗). This school is known as one of the six great schools of Japanese Buddhism in the Nara period (710–794 CE). Mahāyāna Abhidharma Another complete system of Abhidharma thought is elaborated in certain works of the Mahāyāna Yogācāra tradition (which mainly evolved out of the Sarvāstivāda Abhidharma). This Yogācāra Abhidharma can be found in the works of figures like Asanga, Vasubandhu, Sthiramati, Dharmapāla, Śīlabhadra, Xuanzang (Hsüan-tsang), and Vinītadeva. Yogācāra Abhidharmikas discussed many concepts not widely found in non-Mahāyāna Abhidharma, such as the theory of the eight consciousnesses (aṣṭa vijñānakāyāḥ) which