The Innately Pure Mind自性清浄心 （prakṛti-pariśuddha-citta） is a very important concept in Mahāyāna Buddhism. Especially in the Śrīmālādevīsiṃhanādasūtra, there is a chapter named “Innate Purity,” in which the concept of the Innately Pure Mind is explained. The relationship between the mind and defilement is mentioned. But there are still some difficult problems, because there is no further detailed explanation in the sūtra. This was explained in detail in several commentaries on the Śrīmālādevīsiṃhanādasūtra in the Sui and Tang dynasties. According to the explanations of these commentaries, we can get an idea how Chinese Buddhists understood the relationship of mind and defilement, and how they explained the problem of defilement-stained mind. This offers not only an understanding of the Śrīmālādevīsiṃhanādasūtra, but also an answer to the problem of mind and defilement which is common to the concept of Tathāgatagarbha.
