The Abhidharmakośabhāṣya (Sanskrit: अभिधर्मकोशभास्य, lit. Commentary on the Treasury of Abhidharma), Abhidharmakośa (Sanskrit: अभिधर्मकोश) for short (or just Kośa or AKB), is a key text on the Abhidharma written in Sanskrit by the Indian Buddhist scholar Vasubandhu in the 4th or 5th century CE.^[1] The Kośa summarizes the Sarvāstivādin Abhidharma in eight chapters with a total of around 600 verses and then comments on (and often criticizes) it. This text was widely respected and used by schools of Buddhism in India, Tibet and East Asia. Over time, the Abhidharmakośa became the main source of Abhidharma and Sravakayana Buddhism for later Mahāyāna Buddhists.^[2]

In the Kośa, Vasubandhu presents various views on the Abhidharma, mainly those of the Sarvāstivāda-Vaibhāṣika, which he often criticizes from a Sautrāntika perspective.^[3] The Kośa includes an additional chapter in prose refuting the idea of the "person" (pudgala) favoured by some Buddhists of the Pudgalavada school.

The Vaibhāṣika master Samghabhadra considered that Vasubandhu had misrepresented numerous key points of Vaibhāṣika Abhidharma in the Kośa, and saw Vasubandhu as a Sautrāntika (upholder of the sutras). However, Vasubandhu often presents and defends the Vaibhāṣika Abhidharma position on certain topics (contra Sautrāntika).^[4] Because of this, Chinese commentators like Pu Guang do not see Vasubandhu as either a Vaibhāṣika nor as a Sautrāntika.^[5]

The Abhidharmakośabhāṣya (AKB) is a work of Abhidharma, a field of Buddhist philosophy which mainly draws on the Sarvāstivāda Abhidharma tradition. This tradition includes various groupings or "schools", the two main ones being Vaibhāṣika and Sautrāntika.^[6] The main source for the Vaibhāṣika tradition (which was based in Kaśmīra) is the Abhidharma Mahāvibhāṣa Śāstra. The other main tradition of Sarvāstivāda philosophy were those masters who were called "westerners" (Pāścāttya) or "outsiders" (Bāhyaka) and they were mainly based in Gandhara.^[6]

These masters (later known as Sautrāntikas) did not fully accept the Vaibhāṣika philosophy and compiled their own Abhidharma texts, such as the Abhidharma-hṛdaya by Dharmaśrī, which was the first Abhidharma text to provide a series of verses with prose commentary (this is the style that the Kośa follows). This work was very influential on subsequent Abhidharma texts (which imitated its style) and various commentaries were written on it. The Abhidharmakośabhāṣya's style and structure is based on these Sautrāntika Abhidharma works.^[7]

According to K.L. Dhammajoti, in the AKB, Vasubandhu often favors the opinion of the Sautrāntika school against the Sarvāstivāda Vaibhāṣikas (when there is a dispute). For example, he criticizes the doctrine of the existence of the three times (past, present, future), a central Sarvāstivāda doctrine.^[5] However, this is not always the case and he seems to have sometimes also favored certain Vaibhāṣika doctrines (contra Sautrāntika), including the reality of certain mental factors (caittas), the notion of the conjunction (saṃprayoga) of mind (citta) and mental factors and also the Sarvāstivāda doctrine of simultaneous causation (sahabhu-hetu) which was rejected by Sautrantika masters like Śrīlāta.^[4]

The text is divided into the following chapters.

The Sanskrit original of the Abhidharmakośabhāṣya was lost for centuries, and was known to scholarship only through Chinese and Tibetan translations. The work was of such importance to the history of Indian thought that in the 1930s, the great scholar Rāhula Sāṅkṛtyāyana (1893–1963) even re-translated the verses into Sanskrit, from Tibetan, and wrote his own Sanskrit commentary on them.  However, during a subsequent visit to Tibet, Sāṅkṛtyāyana discovered an ancient palm-leaf manuscript of 367 leaves that contained not only Vasubandhu's verses, but his lost commentary.^[9] In 1967 and then in a revised edition of 1975, Prof. P. Pradhan of Utkal University finally published the original Sanskrit text of the Abhidharmakośabhāṣya, Vasubandhu's great work summarizing earlier traditions of the Vibhāṣā school of Buddhist philosophy.^[10]

The Abhidharmakośa-kārikā (the verses) and the Abhidharmakośa-bhāṣya (the auto-commentary) were translated into Chinese in the 6th century by Paramārtha (T1559). They were translated again in the 7th century by Xuanzang (T1560 & T1558).^[11] Other translations and commentaries exist in Tibetan, Chinese, Classical Mongolian and Old Uyghur.

The verses and the commentary were first translated into a European language by Louis de La Vallée-Poussin, published in 1923–1931 in French, which is primarily based on Xuanzang's Chinese translation but also references the Sanskrit text, Paramārtha's Chinese translation, and the Tibetan.

Currently, three complete English translations exist. The first by Leo M. Pruden in 1988 and the second by Gelong Lodrö Sangpo in 2012 are both based on La Vallée-Poussin's French translation. The third by Masahiro Shōgaito in 2014 is a translation of the Uighur translation of Xuanzang's Chinese translation.

• La Vallée-Poussin, Louis de (1923–1931). L'Abhidharmakośa de Vasubandhu. Brussels: Institut belge des hautes études chinoises.
• Pruden, Leo M. (1988–1990). Abhidharmakośabhāṣyam of Vasubandhu (4 volumes). Berkeley, California: Asian Humanities Press. ISBN 0-89581-913-9.
• Lodrö Sangpo, Gelong (2012). Abhidharmakośa-Bhāṣya of Vasubandhu: The Treasury of the Abhidharma and its (Auto) commentary (4 volumes). Delhi: Motilal Banarsidass Publishers. ISBN 978-8120836075.
• Shōgaito, Masahiro (2014). The Uighur Abhidharmakośabhāṣya: Preserved at the Museum of Ethnography in Stockholm. Wiesbaden, Germany: Harrassowitz Verlag. ISBN 978-3-447-10204-9.

There are many commentaries written on this text.

• Abhidharma
• Dharma
• Sarvastivada
• Mulasarvastivada
• Kleshas (Buddhism)
• Mental factors (Buddhism)