This study considers the Tathāgatagarbha theory described in the commentaries on the Prajñāpāramitā literature written during the later periods of Indian Buddhism. In particular, I focus on words mentioned in the Ārya-śatasāhasrikā-pañcaviṃśatisāhasrikāṣṭādaśasāhasrikā prajñāpāramitā-bṛhaṭṭīkā, the Śatasāhasrikā-prajñāpāramitā-bṛhaṭṭīkā (both written by the 9th century), and the Bhagavatyāmnāyānusāriṇī-nāma-vyākhyā (the 12th century). These three commentaries, unlike the eight abhisamaya systems described in the Abhisamayālaṃkāra, are known as annotations of the Prajñāpāramitā-sūtras by three gateways and eleven discourses, but prior study results are a few, and their ideological features are not obvious.
The Abhisamayālaṃkāra has no mention of tathāgatagarbha, and the word itself does not appear in the Abhisamayālāṃkārālokāprajñāpāramitā-vyākhyā of Haribhadra (around 9th century), which explains the Abhisamayālaṃkāra in association with the Abhisamayālāṃkārālokāprajñāpāramitā-vyākhyā. However, the word tathāgatagarbha appears nine times in the Ārya-śatasāhasrikā-pañcaviṃśatisāhasrikāṣṭādaśasāhasrikā-prajñāpāramitā-bṛhaṭṭīkā that I deal with, and it is mentioned twice each in the Śatasāhasrikāprajñāpāramitā-bṛhaṭṭīkā and Bhagavatyāmnāyānusāriṇī-nāma-vyākhyā. In this paper, I only provide the original texts and tentative translations of references to the word tathāgatagarbha in the Ārya-śatasāhasrikā-pañcaviṃśatisāhasrikāṣṭādaśasāhasrikā-prajñāpāramitā-bṛhaṭṭīkā. I would like to discuss other portions on another occasion.